Get Started with web3 Development Easily Based on Ethereum Using FMZ

FMZQuant - May 23 - - Dev Community

EtherEaseWithFMZ Tutorial

Get started with web3 development based on Ethereum using FMZ easily

Ethereum is a smart contract platform based on blockchain technology, which provides a decentralized way to write and deploy smart contracts. Smart contracts are a special type of computer program that can automatically execute on the blockchain and implement various business logic without the need for trusting third parties.

FMZ Quant Trading Platform (FMZ.COM) provides an easy-to-use API, allowing developers to interact more easily with the Ethereum blockchain and its ecosystem. It achieves access to decentralized exchanges (DEX), obtains on-chain data, sends transactions, and other functions.

In this tutorial, the examples are written in JavaScript language, the testing environment uses both Ethereum mainnet and Goerli testnet. And you can also view the API interfaces and related descriptions, code examples used in the tutorial in FMZ platform's API documentation.

FMZ Getting Started

Before learning to use the FMZ Quant Trading Platform, we need to familiarize ourselves with a few basic concepts:

1. FMZ Quant Trading Platform Architecture

After registering and logging in on the FMZ Quant Trading Platform official website (https://www.fmz.com), you can use various functions of the platform. The FMZ website is the management end of the whole system, and user-written programs run on the docker actually. The docker software program can be deployed on various devices, such as servers, computers, etc. When a user writes a program and creates a running instance on the FMZ website, the FMZ platform will communicate with the docker and start a program instance on it.

2. Docker

If you want to run a program instance, you must deploy a docker. The deployment of the docker is also very simple, and there are deployment tutorials on the platform. You can also use the 'One-click Deployment' provided by FMZ to deploy automatically on servers rented on behalf of FMZ.

  • Deploy docker on personal devices

You can deploy and run the docker program on servers, personal computers and other devices, as long as the network is normal (need to be able to access the corresponding target, such as a certain exchange interface, node address, etc.). The main steps of deployment are:

  1. Log in or open the device where the docker program is to be deployed, such as logging into a server or turning on a computer to enter the operating system.
  2. Download the corresponding version of the docker program (depending on the device operating system), download page: https://www.fmz.com/m/add-node

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  1. What you downloaded is a compressed package, need to decompress.
  2. Run the docker program, the docker program is an executable file called robot. Configure the docker communication address, which is unique to each FMZ account, after logging in to FMZ, you can view your own address at https://www.fmz.com/m/add-node page (i.e., ./robot -s node.fmz.com/xxxxx this string of addresses, where the content at xxxxx position is different for each FMZ account). Finally, you need to enter the password of your FMZ account. After configuring these settings, run the docker program.
  • Use FMZ platform's "One-Click Deployment" function

Add a docker page on the FMZ platform, address: https://www.fmz.com/m/add-node

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3. Debugging Tool

FMZ Quant Trading Platform provides a free debugging tool that supports JavaScript, TypeScript, and the page is: https://www.fmz.com/m/debug. Because creating instances to run is billed. During the initial learning period, you can use this debugging tool for testing and learning. Except for the maximum running time limit of 3 minutes, there is no difference between using the debugging tool and creating an instance to run.

When using the TypeScript language, you need to write // @ts-check on the first line of code to switch to TypeScript mode; if not switched, the default is JavaScript language.

4. Platforms

On FMZ, "Platform" is a general concept. For CEX exchanges, it refers to a specific exchange account configuration. For web3, this exchange refers to a configuration information that includes node address and private key configuration.

In the logged-in state of FMZ platform, at https://www.fmz.com/m/add-platform page, you can configure exchange information, where the exchange is a general concept.

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Select Web3, configure RPC node address, configure private key, you can click the lower right corner "Sensitive information will be stored encrypted" to view the security mechanism.

Nodes can be self-built nodes or nodes provided by node service providers. There are many node service providers, such as: Infura. After registration, you can view the node address of your own account. Both mainnet and testnet are available, which is quite convenient. Configure this node address in the

Rpc Address

control shown in the above figure. The label can be named by yourself to distinguish between configured exchange objects.

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In the picture, https://mainnet.infura.io/v3/xxxxxxxxxxxxx is the private Infura ETH mainnet RPC node address.

Interact with Ethereum by using FMZ

After deploying the docker program and configuring the exchange object, you can use FMZ.COM's "Debugging Tool" for testing. Call Ethereum RPC methods and interact with Ethereum, in addition to the several RPC methods listed and introduced in this chapter, other RPC methods can be found by consulting materials, such as https://www.quicknode.com/docs.

We list a few simple examples, starting from the basics. For various languages ​​and tools, there are ways to access web3, as shown in the picture:

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On FMZ, RPC method calls are also encapsulated, and these functions are encapsulated in the FMZ API function exchange.IO. The calling method is exchange.IO("api", "eth", ...). The first parameter is fixed to "api", the second parameter is fixed to "eth", and other parameters depend on the specific RPC method being called.

For output information, we will use the Log function of the FMZ platform. The Log function can accept multiple parameters and then output them in the log area of ​​the "Debug Tool" or "Bot" page on the FMZ platform. The "Debug Tool" page will be our main testing tool.

eth_getBalance

The eth_getBalance method of Ethereum is used to query the ETH balance of an address on Ethereum, and this method requires two parameters.

  • Address to be queried.
  • Label, we usually use "latest". Let's check the Ethereum founder Vitalik Buterin's ETH wallet address, the known address is: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045. 
function main() {
    let ethBalance = exchange.IO("api", "eth", "eth_getBalance", "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "latest")
    Log("ethBalance:", ethBalance)
}
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Already deployed the docker (in the picture: linux/amd64 ...) and configured the exchange object (in the picture: Web3 test), testing code in debugging tool:

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Click the "Execute"' button to run the code and display the results:

ethBalance: 0x117296558f185bbc4c6

The log function prints out the ethBalance variable value as: 0x117296558f185bbc4c6, which is a string type. It is the hexadecimal value of the ETH balance in wei units, with 1e18 wei being equal to 1 ETH. Therefore, it needs to be converted to become a readable decimal ETH balance.

Converting ethBalance into readable data:

function main() {
    let ethBalance = exchange.IO("api", "eth", "eth_getBalance", "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "latest")
    Log("ethBalance:", ethBalance)

    // Converting ethBalance into readable data
    let vitalikEthBalance = parseInt(ethBalance.substring(2), 16) / 1e18
    Log("vitalikEthBalance:", vitalikEthBalance)
}
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Search on https://etherscan.io/:

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However, due to the precision problem of the language itself, there will be deviations in this way of processing. Therefore, FMZ platform has built-in two functions for data processing:

  • BigInt : Convert hexadecimal string to BigInt object.
  • BigDecimal : Convert numeric type objects into computable BigDecimal objects.

Adjust the code again:

function main() {
    let ethBalance = exchange.IO("api", "eth", "eth_getBalance", "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045", "latest")

    // The precision unit of ETH is 1e18
    let ethDecimal = 18
    Log("vitalikEthBalance:", Number((BigDecimal(BigInt(ethBalance)) / BigDecimal(Math.pow(10, ethDecimal))).toString()))
}
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vitalikEthBalance: 5149.6244846875215

eth_chainId

eth_chainId and net_version have similar purposes, so they are tested together. Both of these functions return the Id of the blockchain that the current RPC node is connected to, with the difference being that net_version returns a decimal Id and eth_chainId returns a hexadecimal Id.

Network name corresponding to chainId

1 - ethereum mainnet
2 - morden testnet (deprecated)
3 - ropsten testnet
4 - rinkeby testnet
5 - goerli testnet
11155111 - sepolia testnet
10 - optimism mainnet
69 - optimism kovan testnet
42 - kovan testnet
137 - matic/polygon mainnet
80001 - matic/polygon mumbai testnet
250 - fantom mainnet
100 - xdai mainnet
56 - bsc mainnet
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Test with the configured Ethereum testnet goerli node:

function main() {
    let netVersionId = exchange.IO("api", "eth", "net_version")
    let ethChainId = exchange.IO("api", "eth", "eth_chainId")

    Log("netVersionId:", netVersionId)
    Log("ethChainId:", ethChainId, " , conversion:", parseInt(ethChainId.substring(2), 16))
}
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eth_gasPrice

Call the eth_gasPrice method to query the current gas price on the chain.

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function main() {
    let gasPrice = exchange.IO("api", "eth", "eth_gasPrice")
    Log("gasPrice:", gasPrice, " , conversion:", toAmount(gasPrice, 0))
}
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Here we write a function to convert the hexadecimal string into a readable numerical value: toAmount. In addition, note that the unit of gasPrice is wei, so pass the value 0 to the real parameter corresponding to the formal parameter decimals.

eth_blockNumber

"eth_blockNumber is used to query the block height.

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function main() {
    let blockNumber = exchange.IO("api", "eth", "eth_blockNumber")
    Log(toAmount(blockNumber, 0))
}
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Run in debugging tool:

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Search on https://etherscan.io/:

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eth_getBlockByNumber

Query block information.

function main() {
    let blockNumber = exchange.IO("api", "eth", "eth_blockNumber")    
    Log(blockNumber)
    let blockMsg = exchange.IO("api", "eth", "eth_getBlockByNumber", blockNumber, true)
    Log(typeof(blockMsg), blockMsg)

    // Due to the excessive content of Log output, it will be truncated automatically, so traverse each field of the returned block information and print them one by one
    for (let key in blockMsg) {
        Log("key:", key, ", val:", blockMsg[key])
    }
}
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Executing in the "Debugging Tool" can obtain the following information:

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Read contract information

Many smart contract applications run on Ethereum, and ENS is one of them. ENS, or Ethereum Name Service, is a decentralized domain name resolution service based on the Ethereum blockchain.
Do you remember the example in the tutorial where we checked the balance of Ethereum founder Vitalik Buterin's wallet? One of Vitalik Buterin's wallet addresses is: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045. So how do we know the address? In fact, it can be queried through the ENS smart contract using an intuitive name vitalik.eth.

The following content in this chapter uses Ethereum mainnet environment, according to the ENS documentation, Hashing Names are required for querying Ethereum domain names. Use the following code to process vitalik.eth.

function nameHash(name) {
    if (name == "") {
        return "0000000000000000000000000000000000000000000000000000000000000000"
    } else {
        let arr = name.split(".")
        let label = arr[0]

        arr.shift()
        let remainder = arr.join(".")
        return Encode("sha3.keccak256", "hex", "hex", nameHash(remainder) + Encode("sha3.keccak256", "raw", "hex", label))
    }
}
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In the above code example, we saw another unfamiliar function Encode. This function is an API function of the FMZ platform and is specifically used for encoding operations on the FMZ platform. The function supports multiple encoding methods and various hash algorithms.

Encode(algo, inputFormat, outputFormat, data, keyFormat, key string)
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According to the description in the ENS document, use the sha3.keccak256 algorithm to process data.

Call the nameHash function, for example: Log(nameHash("vitalik.eth")), you can get: ee6c4522aab0003e8d14cd40a6af439055fd2577951148c14b6cea9a53475835, and you need to add the "0x" prefix. 0xee6c4522aab0003e8d14cd40a6af439055fd2577951148c14b6cea9a53475835 is used as the parameter of the resolver method in ENS smart contract.

let ensNode = "0x" + nameHash("vitalik.eth")    // Prepare the parameters ensNode for calling the resolver method
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According to the ENS documentation, the contract address for ENS smart contract applications is: 0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e. Before calling the resolver method of the smart contract, we also need to prepare the ABI of the contract.

Register ABI

Upon learning this, you may ask: what is the ABI of a smart contract?

ABI, or Application Binary Interface, is the interface standard for smart contracts to communicate with the external world.
The ABI of a smart contract defines the contract's function interfaces, parameter types, return values, and other information, as well as specifications for calling the contract and passing parameters.

The ABI of a smart contract is usually stored in JSON format and contains the following information:

Contract function interfaces: function names, parameter lists, return values, etc.
Function parameter types: such as uint256, bool, string etc.
Encoding methods for input and output parameters of functions: Smart contracts use an encoding method called Solidity ABI to encode input and output parameters of functions so that they can interact with Ethereum network.
In Ethereum network ,the ABI of a smart contract is used to call its functions. When you need to call a contract function, you need to provide the name of the function, its parameters, and bytecode encoded according to ABI encoding method.
Ethereum nodes will package this information into transactions and send them out on Ethereum network for execution.

In Solidity language,the keyword 'interface' can be used define ABIs for smart contracts. Ethereum development tools like Remix IDE ,Truffle also provide editing & generation tools making it easier developers create & use ABIs.
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Extract the resolver method part from ENS's ABI, or you can use the complete ABI. You can query the contract's ABI on https://etherscan.io/ or obtain the ABI through other channels (e.g., relevant project documentation).

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let abiENS_resolver = `[{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"resolver","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"}]`
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Here we are going to learn a new invocation method on the FMZ platform, exchange.IO("abi", address, abiContent), which is used to register ABI. The address parameter is the smart contract address and the abiContent parameter is the corresponding smart contract ABI (string).

let abiENS_resolver = `[{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"resolver","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"}]`
exchange.IO("abi", "0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e", abiENS_resolver)  // 0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e is the address of the ENS smart contract deployed on the Ethereum mainnet
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Methods for Calling Smart Contracts

Next, you can call the resolver method of the ENS smart contract, which returns the address of the ENS: Public Resolver contract.

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let resolverAddress = exchange.IO("api", "0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e", "resolver", ensNode)
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Use the ENS: Public Resolver contract's addr method to obtain Vitalik Buterin's wallet address. To call the ENS: Public Resolver contract, you still need to register the ABI first. The ABI information for this smart contract can still be obtained from https://etherscan.io/.

let abiENSPublicResolver = `[{"inputs":[{"internalType":"contract ENS","name":"_ens","type":"address"}],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":true,"internalType":"uint256","name":"contentType","type":"uint256"}],"name":"ABIChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"address","name":"a","type":"address"}],"name":"AddrChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"uint256","name":"coinType","type":"uint256"},{"indexed":false,"internalType":"bytes","name":"newAddress","type":"bytes"}],"name":"AddressChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":true,"internalType":"address","name":"owner","type":"address"},{"indexed":true,"internalType":"address","name":"target","type":"address"},{"indexed":false,"internalType":"bool","name":"isAuthorised","type":"bool"}],"name":"AuthorisationChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"bytes","name":"hash","type":"bytes"}],"name":"ContenthashChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"bytes","name":"name","type":"bytes"},{"indexed":false,"internalType":"uint16","name":"resource","type":"uint16"},{"indexed":false,"internalType":"bytes","name":"record","type":"bytes"}],"name":"DNSRecordChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"bytes","name":"name","type":"bytes"},{"indexed":false,"internalType":"uint16","name":"resource","type":"uint16"}],"name":"DNSRecordDeleted","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"DNSZoneCleared","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":true,"internalType":"bytes4","name":"interfaceID","type":"bytes4"},{"indexed":false,"internalType":"address","name":"implementer","type":"address"}],"name":"InterfaceChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"string","name":"name","type":"string"}],"name":"NameChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"bytes32","name":"x","type":"bytes32"},{"indexed":false,"internalType":"bytes32","name":"y","type":"bytes32"}],"name":"PubkeyChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":true,"internalType":"string","name":"indexedKey","type":"string"},{"indexed":false,"internalType":"string","name":"key","type":"string"}],"name":"TextChanged","type":"event"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"uint256","name":"contentTypes","type":"uint256"}],"name":"ABI","outputs":[{"internalType":"uint256","name":"","type":"uint256"},{"internalType":"bytes","name":"","type":"bytes"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"addr","outputs":[{"internalType":"address payable","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"uint256","name":"coinType","type":"uint256"}],"name":"addr","outputs":[{"internalType":"bytes","name":"","type":"bytes"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"","type":"bytes32"},{"internalType":"address","name":"","type":"address"},{"internalType":"address","name":"","type":"address"}],"name":"authorisations","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"clearDNSZone","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"contenthash","outputs":[{"internalType":"bytes","name":"","type":"bytes"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes32","name":"name","type":"bytes32"},{"internalType":"uint16","name":"resource","type":"uint16"}],"name":"dnsRecord","outputs":[{"internalType":"bytes","name":"","type":"bytes"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes32","name":"name","type":"bytes32"}],"name":"hasDNSRecords","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes4","name":"interfaceID","type":"bytes4"}],"name":"interfaceImplementer","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"results","type":"bytes[]"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"name","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"pubkey","outputs":[{"internalType":"bytes32","name":"x","type":"bytes32"},{"internalType":"bytes32","name":"y","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"uint256","name":"contentType","type":"uint256"},{"internalType":"bytes","name":"data","type":"bytes"}],"name":"setABI","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"uint256","name":"coinType","type":"uint256"},{"internalType":"bytes","name":"a","type":"bytes"}],"name":"setAddr","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"address","name":"a","type":"address"}],"name":"setAddr","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"address","name":"target","type":"address"},{"internalType":"bool","name":"isAuthorised","type":"bool"}],"name":"setAuthorisation","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes","name":"hash","type":"bytes"}],"name":"setContenthash","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes","name":"data","type":"bytes"}],"name":"setDNSRecords","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes4","name":"interfaceID","type":"bytes4"},{"internalType":"address","name":"implementer","type":"address"}],"name":"setInterface","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"string","name":"name","type":"string"}],"name":"setName","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes32","name":"x","type":"bytes32"},{"internalType":"bytes32","name":"y","type":"bytes32"}],"name":"setPubkey","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"string","name":"key","type":"string"},{"internalType":"string","name":"value","type":"string"}],"name":"setText","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes4","name":"interfaceID","type":"bytes4"}],"name":"supportsInterface","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"pure","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"string","name":"key","type":"string"}],"name":"text","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"}]`
exchange.IO("abi", resolverAddress, abiENSPublicResolver)
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Finally, call the ENS: Public Resolver contract's addr method, with the parameter still being ensNode.

let vitalikAddress = exchange.IO("api", resolverAddress, "addr", ensNode)
Log("vitalikAddress:", vitalikAddress)
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Log function output:

vitalikAddress: 0xd8da6bf26964af9d7eed9e03e53415d37aa96045
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Call the Complete Code of ENS 

function nameHash(name) {
    if (name == "") {
        return "0000000000000000000000000000000000000000000000000000000000000000"
    } else {
        let arr = name.split(".")
        let label = arr[0]

        arr.shift()
        let remainder = arr.join(".")
        return Encode("sha3.keccak256", "hex", "hex", nameHash(remainder) + Encode("sha3.keccak256", "raw", "hex", label))
    }
}

function main() {
    // Calculate the name
    let ensNode = "0x" + nameHash("vitalik.eth")    

    // Register ENS contract
    let abiENS_resolver = `[{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"resolver","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"}]`
    exchange.IO("abi", "0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e", abiENS_resolver)
    let resolverAddress = exchange.IO("api", "0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e", "resolver", ensNode)

    // Register ENS Public Resolver contract
    let abiENSPublicResolver = `[{"inputs":[{"internalType":"contract ENS","name":"_ens","type":"address"}],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":true,"internalType":"uint256","name":"contentType","type":"uint256"}],"name":"ABIChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"address","name":"a","type":"address"}],"name":"AddrChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"uint256","name":"coinType","type":"uint256"},{"indexed":false,"internalType":"bytes","name":"newAddress","type":"bytes"}],"name":"AddressChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":true,"internalType":"address","name":"owner","type":"address"},{"indexed":true,"internalType":"address","name":"target","type":"address"},{"indexed":false,"internalType":"bool","name":"isAuthorised","type":"bool"}],"name":"AuthorisationChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"bytes","name":"hash","type":"bytes"}],"name":"ContenthashChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"bytes","name":"name","type":"bytes"},{"indexed":false,"internalType":"uint16","name":"resource","type":"uint16"},{"indexed":false,"internalType":"bytes","name":"record","type":"bytes"}],"name":"DNSRecordChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"bytes","name":"name","type":"bytes"},{"indexed":false,"internalType":"uint16","name":"resource","type":"uint16"}],"name":"DNSRecordDeleted","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"DNSZoneCleared","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":true,"internalType":"bytes4","name":"interfaceID","type":"bytes4"},{"indexed":false,"internalType":"address","name":"implementer","type":"address"}],"name":"InterfaceChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"string","name":"name","type":"string"}],"name":"NameChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":false,"internalType":"bytes32","name":"x","type":"bytes32"},{"indexed":false,"internalType":"bytes32","name":"y","type":"bytes32"}],"name":"PubkeyChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"bytes32","name":"node","type":"bytes32"},{"indexed":true,"internalType":"string","name":"indexedKey","type":"string"},{"indexed":false,"internalType":"string","name":"key","type":"string"}],"name":"TextChanged","type":"event"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"uint256","name":"contentTypes","type":"uint256"}],"name":"ABI","outputs":[{"internalType":"uint256","name":"","type":"uint256"},{"internalType":"bytes","name":"","type":"bytes"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"addr","outputs":[{"internalType":"address payable","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"uint256","name":"coinType","type":"uint256"}],"name":"addr","outputs":[{"internalType":"bytes","name":"","type":"bytes"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"","type":"bytes32"},{"internalType":"address","name":"","type":"address"},{"internalType":"address","name":"","type":"address"}],"name":"authorisations","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"clearDNSZone","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"contenthash","outputs":[{"internalType":"bytes","name":"","type":"bytes"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes32","name":"name","type":"bytes32"},{"internalType":"uint16","name":"resource","type":"uint16"}],"name":"dnsRecord","outputs":[{"internalType":"bytes","name":"","type":"bytes"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes32","name":"name","type":"bytes32"}],"name":"hasDNSRecords","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes4","name":"interfaceID","type":"bytes4"}],"name":"interfaceImplementer","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"results","type":"bytes[]"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"name","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"}],"name":"pubkey","outputs":[{"internalType":"bytes32","name":"x","type":"bytes32"},{"internalType":"bytes32","name":"y","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"uint256","name":"contentType","type":"uint256"},{"internalType":"bytes","name":"data","type":"bytes"}],"name":"setABI","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"uint256","name":"coinType","type":"uint256"},{"internalType":"bytes","name":"a","type":"bytes"}],"name":"setAddr","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"address","name":"a","type":"address"}],"name":"setAddr","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"address","name":"target","type":"address"},{"internalType":"bool","name":"isAuthorised","type":"bool"}],"name":"setAuthorisation","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes","name":"hash","type":"bytes"}],"name":"setContenthash","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes","name":"data","type":"bytes"}],"name":"setDNSRecords","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes4","name":"interfaceID","type":"bytes4"},{"internalType":"address","name":"implementer","type":"address"}],"name":"setInterface","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"string","name":"name","type":"string"}],"name":"setName","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"bytes32","name":"x","type":"bytes32"},{"internalType":"bytes32","name":"y","type":"bytes32"}],"name":"setPubkey","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"string","name":"key","type":"string"},{"internalType":"string","name":"value","type":"string"}],"name":"setText","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes4","name":"interfaceID","type":"bytes4"}],"name":"supportsInterface","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"pure","type":"function"},{"constant":true,"inputs":[{"internalType":"bytes32","name":"node","type":"bytes32"},{"internalType":"string","name":"key","type":"string"}],"name":"text","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"}]`
    exchange.IO("abi", resolverAddress, abiENSPublicResolver)
    let vitalikAddress = exchange.IO("api", resolverAddress, "addr", ensNode)
    Log("vitalikAddress:", vitalikAddress)
}
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Send ETH

In the previous course chapters, we have learned how to configure private keys. How do we know the wallet address corresponding to this private key for the configured exchange object? On FMZ, you can use the exchange.IO("address") function to obtain the wallet address corresponding to the configured private key.

The following content in this chapter uses Goerli testnet environment, so the node I am using is: https://goerli.infura.io/v3/*******, and Infura assigns different node addresses for each registered user. Here the ******* hides specific content.

function main() {
    let walletAddress = exchange.IO("address")
    Log("Testnet goerli wallet address:", walletAddress)
}
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After knowing your wallet address, you can use Ethereum's RPC method eth_getTransactionCount to query the transaction count of the wallet address. In Ethereum, this count is very common, and it's actually the nonce parameter that needs to be passed in during transfer operations. In Ethereum, nonce is a unique number used to ensure that each transaction is unique. It is an increasing number, and it will automatically increase every time a new transaction is sent. Therefore, when you send a transaction to a smart contract, you need to provide a nonce to ensure that the transaction is unique and in the correct order. We can find this information in some materials and documents:

https://goethereumbook.org/en/

Image description

Here, the PendingNonceAt function in the Ethereum library of Go language is actually calling the eth_getTransactionCount method. In previous courses, we have also learned how to call RPC methods. Here we use the exchange.IO("api", "eth", ...) function again.

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function main() {
    let walletAddress = exchange.IO("address")
    Log("Testnet goerli wallet address:", walletAddress)

    /**
    * eth_getTransactionCount
    * @param address - string - The address from which the transaction count to be checked.
    * @param blockNumber - string - The block number as a string in hexadecimal format or tags.
    * @returns The integer of the number of transactions sent from an address encoded as hexadecimal.
    */
    let nonce: string = exchange.IO("api", "eth", "eth_getTransactionCount", walletAddress, "pending")
    Log("wallet address:", walletAddress, "current nonce：", nonce, ", convert to decimal:", toAmount(nonce, 0))
}
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Before explaining the transfer operation, let's briefly understand some concepts. When transferring on Ethereum, a certain amount of ETH tokens will be consumed (as gas fees). The gas fee is determined by two parameters:

  • gasPrice

    However, the gas fees on the Ethereum network always fluctuate according to market demand and the fees users are willing to pay, so writing a fixed gas fee in the code is sometimes not an ideal choice. We can use the eth_gasPrice method we learned before, which can obtain the average gas price.

  • gasLimit

    A standard Ether transfer has a gas limit of 21,000 units.

After understanding the concepts of nonce, gasPrice, and gasLimit, you can test the transfer. FMZ provides a very simple and easy-to-use transfer function.

exchange.IO("api", "eth", "send", toAddress, toAmount)
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When it's used for transfers, the third parameter of exchange.IO is fixed as "send", the toAddress parameter is the address receiving ETH during the transfer, and toAmount is the amount of ETH transferred.

The parameters nonce, gasPrice, and gasLimit can all use system default values automatically obtained on FMZ. They can also be specified:

exchange.IO("api", "eth", "send", toAddress, toAmount, {gasPrice: 5000000000, gasLimit: 21000, nonce: 100})
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Next, we will transfer a certain amount of ETH to a specific address on the goerli test network:

function toInnerAmount(s, decimals) {
    return (BigDecimal(s)*BigDecimal(Math.pow(10, decimals))).toFixed(0)
}

function main() {
    let walletAddress = exchange.IO("address")
    Log("Testnet goerli wallet address:", walletAddress)

    let ret = exchange.IO("api", "eth", "send", "0x4D75a08E870674E68cAE611f329A27f446A66813", toInnerAmount(0.01, 18))
    return ret // return Transaction Hash : 0xa6f9f51b00d8ae850b0f204380b59da98f4bbce34b813577d3d948f61de4734e
}
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Because the unit of Ethereum transfer amount is wei, a custom function toInnerAmount needs to be used to process the value in wei units.

Query Transaction Hash: 0xa6f9f51b00d8ae850b0f204380b59da98f4bbce34b813577d3d948f61de4734e on https://etherscan.io/.

Image description

You can also write code to query transfer hash 0xa6f9f51b00d8ae850b0f204380b59da98f4bbce34b813577d3d948f61de4734e, using the eth_getTransactionReceipt method for queries.

function main() {
    let transHash = "0xa6f9f51b00d8ae850b0f204380b59da98f4bbce34b813577d3d948f61de4734e"
    let info = exchange.IO("api", "eth", "eth_getTransactionReceipt", transHash)
    return info
}
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Query result:

{
    "cumulativeGasUsed": "0x200850",
    "effectiveGasPrice": "0x1748774421",
    "transactionHash": "0xa6f9f51b00d8ae850b0f204380b59da98f4bbce34b813577d3d948f61de4734e",
    "type": "0x0",
    "blockHash": "0x6bdde8b0f0453ecd24eecf7c634d65306f05511e0e8f09f9ed3f59eee2d06ac7",
    "contractAddress": null,
    "blockNumber": "0x868a50",
    "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
    "gasUsed": "0x5208",
    "to": "0x4d75a08e870674e68cae611f329a27f446a66813",
    "status": "0x1",
    "transactionIndex": "0x23",
    "from": "0x6b3f11d807809b0b1e5e3243df04a280d9f94bf4",
    "logs": []
}
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Description corresponding to each field:

blockHash - The hash value of the block where the transaction is located.
blockNumber - The block number of the block where the transaction is located, encoded in hexadecimal.
contractAddress - If it's a contract creation, the address of the contract; otherwise null.
cumulativeGasUsed - The total gas used when executing this transaction in the block.
effectiveGasPrice - Total base fee plus tip per unit of gas.
from - Sender's address.
gasUsed - Gas used by this specific transaction.
logs - Array of log objects generated by this transaction.
  address - Address that generated this log.
  topics - Data array with 0 to 4 indexed log parameters, each with 32 bytes. In Solidity, first topic is event signature hash (e.g., Deposit(address,bytes32,uint256)), unless you declare an event using anonymous specifier.
  data - Non-indexed parameters for logs with length of 32 bytes.
  blockNumber - The block number of the block where this log is located.
  transactionHash - Transaction hash at time when log was created. Null if pending state.
  transactionIndex - Index position during creation. Null if pending state.
  blockHash - The hash value for containing block.
  logIndex - Hexadecimal-encoded integer index position within containing block. Null if pending state.
  removed - True if deleted due to chain reorganization; false for valid logs.
logsBloom - Bloom filter for retrieving related logs.
status - Hexadecimal-encoded value either being '1' (success) or '0' (failure).
to - Receiving party's address; null for contract creation transactions.
transactionHash - The hash value associated with given transaction.
transactionIndex - Hexadecimal-encoded index position within its respective containing-block.
type - Type value.
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Call Ethereum Smart Contract

In the chapter on "Reading Contract Information", we used a complete example to call the method of ENS contract deployed on Ethereum to obtain Vitalik Buterin's wallet address. These methods belong to Read methods, and calling these methods does not require gas (remember what we talked about gas before?). In this chapter, we will call some Write methods of smart contracts on Ethereum and pay for gas. These operations will be verified by each node and miner in the entire network and change the blockchain state.

ERC20

For the ERC20 contract (ERC20 token contract), FMZ platform lists the ABI of the ERC20 contract ABI as a common ABI built directly into the system, eliminating the step of registering the ABI. We have also learned about ABI in previous tutorials when we registered ENS contract's ABI before calling ENS contract methods.

To better understand ABI, you can check it out before using it. Here is the ABI for ERC20 contracts:

[{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"guy","type":"address"},{"name":"wad","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"wad","type":"uint256"}],"name":"withdraw","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"deposit","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"},{"name":"","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"guy","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Withdrawal","type":"event"}]
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This section uses the Goerli testnet environment.

balanceOf

Next, let's practice again how to call the Read method of a contract to read contract information, call the balanceOf method of ERC20 contract to query token balance, the balanceOf method has only one parameter, which is not named, but can be identified by its type as an address (i.e., the address of the token being queried). Since the returned data is not in units of one token, we also need the precision data of tokens for conversion. The precision of tokens can be obtained by using decimals method in ERC20 contracts. We will use Ethereum testnet goerli for testing. Please note that token contract addresses may vary on different chains.

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function main() {
    let walletAddress = exchange.IO("address")

    // goerli WETH address 
    let wethAddress = "0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6"
    // goerli LINK address 
    let linkAddress = "0x326C977E6efc84E512bB9C30f76E30c160eD06FB"

    // Since it is an ERC20 contract, FMZ has built-in ABI registration, so there is no need to register ERC20 ABI here.
    let wethDecimals = exchange.IO("api", wethAddress, "decimals")
    let linkDecimals = exchange.IO("api", linkAddress, "decimals")

    let wethBalance = exchange.IO("api", wethAddress, "balanceOf", walletAddress)
    let linkBalance = exchange.IO("api", linkAddress, "balanceOf", walletAddress)
    Log("WETH precision:", wethDecimals, "wethBalance:", toAmount(wethBalance, wethDecimals))
    Log("LINK precision:", linkDecimals, "linkBalance:", toAmount(linkBalance, linkDecimals))
}
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By running the above code, you can query the current wallet's WETH and LINK token balance:

WETH precision: 18 wethBalance: 0
LINK precision: 18 linkBalance: 51.41374973681053

deposit

We can see that the balance of WETH tokens in the wallet is 0. Next, we will continue to interact with the ERC20 smart contract of WETH tokens, and this time we will call the Write type method: deposit.
The function of the deposit method is simply to exchange a certain amount of ETH for WETH. It should be noted that there are no parameters for the deposit method (which can be observed by checking ABI). The payable attribute of this method is true, so when calling it, you need to set the transferable ETH (payableAmount) quantity to specify the amount of ETH deposited.

Pay attention when calling smart contract methods:
If the called method has a payable attribute, you need to add a transfer ETH value (the fourth parameter of the exchange.IO function) after the method name, which can be a numeric type or a string form of numeric value.

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(s, decimals) {
    return (BigDecimal(s)*BigDecimal(Math.pow(10, decimals))).toFixed(0)
}

function main() {
    let walletAddress = exchange.IO("address")

    // goerli WETH address 
    let wethAddress = "0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6"

    // Since it is an ERC20 contract, FMZ has built-in ABI registration, so there is no need to register ERC20 ABI here.
    let wethDecimals = exchange.IO("api", wethAddress, "decimals")

    let wethBalance = exchange.IO("api", wethAddress, "balanceOf", walletAddress)
    Log("WETH precision:", wethDecimals, "wethBalance:", toAmount(wethBalance, wethDecimals))
    let ethBalance = exchange.IO("api", "eth", "eth_getBalance", walletAddress, "latest")
    Log("ETH precision:", 18, "ethBalance:", toAmount(ethBalance, 18))

    // Call the deposit method, since deposit is a method outside of the ERC20 standard, we need to register the ABI for this method here
    let abiWETH = `[{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"guy","type":"address"},{"name":"wad","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"wad","type":"uint256"}],"name":"withdraw","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"deposit","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"},{"name":"","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"guy","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Withdrawal","type":"event"}]`
    exchange.IO("abi", wethAddress, abiWETH)

    let payableAmount = toInnerAmount(0.01, 18)
    let ret = exchange.IO("api", wethAddress, "deposit", payableAmount)
    Log("Transaction Hash:", ret)
}
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WETH precision: 18 wethBalance: 0
ETH precision: 18 ethBalance: 0.14333094664072302
Transaction Hash: 0xaf15b0b0e25a81eda583295e82b249e2d02e4eafebecc906470ccc2c89e23563

Image description

Check the balance of WETH and ETH again:

WETH precision: 18 wethBalance: 0.01
ETH precision: 18 ethBalance: 0.1333309358060905

Before calling deposit, WETH is 0 and ETH is 0.14333094664072302. After calling deposit, WETH is 0.01 and ETH is 0.1333309358060905. It can be seen that it has exchanged 0.01 ETH for WETH successfully.

transfer

ERC20 tokens can also be transferred, using the transfer method to transfer 0.01 WETH tokens to the address 0x4D75a08E870674E68cAE611f329A27f446A66813. The transfer method has two parameters, the first parameter dst is the wallet address of the transfer recipient, and the second parameter wad is the transfer amount.

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(s, decimals) {
    return (BigDecimal(s)*BigDecimal(Math.pow(10, decimals))).toFixed(0)
}

function waitMined (tx) {
    for (var i = 0 ; i < 10 ; i++) {
        Sleep(5000)
        let info = exchange.IO("api", "eth", "eth_getTransactionReceipt", tx)
        if (info && info.gasUsed) {
            Log(info)
            return true
        }
        Log('Transaction not yet mined', tx)
    }
    return false 
}

function main() {
    let walletAddress = exchange.IO("address")

    // goerli WETH address 
    let wethAddress = "0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6"

    // Since it is an ERC20 contract, FMZ has built-in ABI registration, there is no need to register ERC20 ABI here.
    let wethDecimals = exchange.IO("api", wethAddress, "decimals")
    let wethBalance = exchange.IO("api", wethAddress, "balanceOf", walletAddress)
    Log("WETH precision:", wethDecimals, "wethBalance:", toAmount(wethBalance, wethDecimals))

    let dst = "0x4D75a08E870674E68cAE611f329A27f446A66813"
    let wad = toInnerAmount(0.01, wethDecimals)
    let tx = exchange.IO("api", wethAddress, "transfer", dst, wad)   
    Log("Transaction Hash:", tx)
    waitMined(tx)

    wethBalance = exchange.IO("api", wethAddress, "balanceOf", walletAddress)
    Log("WETH precision:", wethDecimals, "wethBalance:", toAmount(wethBalance, wethDecimals))
}
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In the above example, a custom function waitMined is used. In fact, we are not unfamiliar with the function of this function. Do you remember the eth_getTransactionReceipt method? The purpose of this waitMined custom function is to wait for the result of the passed Transaction Hash.

For this WETH transfer, interested readers can also query the Transaction Hash 0x2fafb62b548a1fffb0f3189429e3c5a4f57ddafb0acbc0678d8b3cf0a2f7c92c to view details (note that it is on testnet goerli).

withdraw

This time we will exchange WETH back to ETH, using the withdraw method, which has only one parameter wad, simply put, it is used to set how much ETH to exchange back.

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(s, decimals) {
    return (BigDecimal(s)*BigDecimal(Math.pow(10, decimals))).toFixed(0)
}

function main() {
    let walletAddress = exchange.IO("address")

    // goerli WETH address 
    let wethAddress = "0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6"

    // Since it is an ERC20 contract, FMZ has built-in ABI registration, there is no need to register ERC20 ABI here.
    let wethDecimals = exchange.IO("api", wethAddress, "decimals")

    let wethBalance = exchange.IO("api", wethAddress, "balanceOf", walletAddress)
    Log("WETH precision:", wethDecimals, "wethBalance:", toAmount(wethBalance, wethDecimals))
    let ethBalance = exchange.IO("api", "eth", "eth_getBalance", walletAddress, "latest")
    Log("ETH precision:", 18, "ethBalance:", toAmount(ethBalance, 18))

    let abiWETH = `[{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"guy","type":"address"},{"name":"wad","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"wad","type":"uint256"}],"name":"withdraw","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"deposit","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"},{"name":"","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"guy","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Withdrawal","type":"event"}]`
    exchange.IO("abi", wethAddress, abiWETH)

    let wad = toInnerAmount(0.01, 18)
    let ret = exchange.IO("api", wethAddress, "withdraw", wad)
    Log("Transaction Hash:", ret)
}
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Transaction Hash: 0x446423c841451a8d04428a075b556eb5564186b09926da915f5da1c9837d2af4

From the above code, it can be seen that it is basically the same as the previous example, except that the method called in the last step is changed to withdraw, before calling:

WETH precision: 18 wethBalance: 0.01
ETH precision: 18 ethBalance: 0.11322979983231546

Query again:

WETH precision: 18 wethBalance: 0
ETH precision: 18 ethBalance: 0.1231207156449464

We can see that 0.01 WETH has been exchanged back to ETH.

Uniswap V3

Uniswap V3 is a decentralized transaction protocol built on the Ethereum blockchain, used to facilitate cryptocurrency trading and liquidity provision. It consists of a series of smart contracts, including core contracts, pool contracts, factory contracts, router contracts, etc.

The following contracts are mainly used when querying the current exchange price and performing exchange operations using Uniswap:

  • Router (Router contract) This is the contract used to execute transactions, allowing the user to perform a trade operation by specifying a trade path and parameters.
  • Pool (Pool contract) Pool contracts are the key component in Uniswap for storing and managing the liquidity of a given asset pair. Each asset pair has a corresponding pool contract, which contains information about the funds, price range, fee settings, etc. provided by the liquidity provider. The pool contract is responsible for processing transactions, calculating the status of the pool, and ensuring the smooth execution of transactions.
  • Factory (Factory contract) Factory contracts are the contracts used to create and manage Uniswap pool contracts. When users wish to create new asset pairs, they deploy new pool contracts by interacting with the factory contract. Factory contracts are responsible for coordinating the creation and initialization of pool contracts, enabling users to create new asset pairs dynamically.

As we have learned in previous lessons, let's review how to register the


 of smart contracts in strategy code on the FMZ Quant Trading Platform. The process of obtaining the ABI of smart contracts has been discussed in previous lessons and will not be repeated here. 
Three Uniswap smart contract ABIs need to be registered, using the Ethereum mainnet as an example:



```javascript
var abiRoute = '[{"inputs":[{"internalType":"address","name":"_factoryV2","type":"address"},{"internalType":"address","name":"factoryV3","type":"address"},{"internalType":"address","name":"_positionManager","type":"address"},{"internalType":"address","name":"_WETH9","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH9","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes","name":"data","type":"bytes"}],"name":"callPositionManager","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"paths","type":"bytes[]"},{"internalType":"uint128[]","name":"amounts","type":"uint128[]"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactInputParams","name":"params","type":"tuple"}],"name":"exactInput","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactInputSingleParams","name":"params","type":"tuple"}],"name":"exactInputSingle","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactOutputParams","name":"params","type":"tuple"}],"name":"exactOutput","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactOutputSingleParams","name":"params","type":"tuple"}],"name":"exactOutputSingle","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"factory","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"factoryV2","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"getApprovalType","outputs":[{"internalType":"enum IApproveAndCall.ApprovalType","name":"","type":"uint8"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint256","name":"tokenId","type":"uint256"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"}],"internalType":"struct IApproveAndCall.IncreaseLiquidityParams","name":"params","type":"tuple"}],"name":"increaseLiquidity","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"int24","name":"tickLower","type":"int24"},{"internalType":"int24","name":"tickUpper","type":"int24"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"internalType":"struct IApproveAndCall.MintParams","name":"params","type":"tuple"}],"name":"mint","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes32","name":"previousBlockhash","type":"bytes32"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"results","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"positionManager","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"pull","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"refundETH","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermit","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowed","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowedIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapExactTokensForTokens","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMax","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapTokensForExactTokens","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"int256","name":"amount0Delta","type":"int256"},{"internalType":"int256","name":"amount1Delta","type":"int256"},{"internalType":"bytes","name":"_data","type":"bytes"}],"name":"uniswapV3SwapCallback","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"value","type":"uint256"}],"name":"wrapETH","outputs":[],"stateMutability":"payable","type":"function"},{"stateMutability":"payable","type":"receive"}]';
var abiPool = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"name\":\"Burn\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"name\":\"Collect\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"name\":\"CollectProtocol\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"paid0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"paid1\",\"type\":\"uint256\"}],\"name\":\"Flash\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint16\",\"name\":\"observationCardinalityNextOld\",\"type\":\"uint16\"},{\"indexed\":false,\"internalType\":\"uint16\",\"name\":\"observationCardinalityNextNew\",\"type\":\"uint16\"}],\"name\":\"IncreaseObservationCardinalityNext\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"}],\"name\":\"Initialize\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"name\":\"Mint\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol0Old\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol1Old\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol0New\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol1New\",\"type\":\"uint8\"}],\"name\":\"SetFeeProtocol\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"indexed\":false,\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"},{\"indexed\":false,\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"}],\"name\":\"Swap\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"}],\"name\":\"burn\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collect\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collectProtocol\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"factory\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"fee\",\"outputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal0X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal1X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"flash\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"}],\"name\":\"increaseObservationCardinalityNext\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"}],\"name\":\"initialize\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"liquidity\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"maxLiquidityPerTick\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"mint\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"name\":\"observations\",\"outputs\":[{\"internalType\":\"uint32\",\"name\":\"blockTimestamp\",\"type\":\"uint32\"},{\"internalType\":\"int56\",\"name\":\"tickCumulative\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityCumulativeX128\",\"type\":\"uint160\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint32[]\",\"name\":\"secondsAgos\",\"type\":\"uint32[]\"}],\"name\":\"observe\",\"outputs\":[{\"internalType\":\"int56[]\",\"name\":\"tickCumulatives\",\"type\":\"int56[]\"},{\"internalType\":\"uint160[]\",\"name\":\"secondsPerLiquidityCumulativeX128s\",\"type\":\"uint160[]\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"name\":\"positions\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside0LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside1LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"protocolFees\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"token0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"token1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint8\",\"name\":\"feeProtocol0\",\"type\":\"uint8\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol1\",\"type\":\"uint8\"}],\"name\":\"setFeeProtocol\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"slot0\",\"outputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"},{\"internalType\":\"uint16\",\"name\":\"observationIndex\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinality\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol\",\"type\":\"uint8\"},{\"internalType\":\"bool\",\"name\":\"unlocked\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"}],\"name\":\"snapshotCumulativesInside\",\"outputs\":[{\"internalType\":\"int56\",\"name\":\"tickCumulativeInside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityInsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsInside\",\"type\":\"uint32\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"bool\",\"name\":\"zeroForOne\",\"type\":\"bool\"},{\"internalType\":\"int256\",\"name\":\"amountSpecified\",\"type\":\"int256\"},{\"internalType\":\"uint160\",\"name\":\"sqrtPriceLimitX96\",\"type\":\"uint160\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"swap\",\"outputs\":[{\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int16\",\"name\":\"\",\"type\":\"int16\"}],\"name\":\"tickBitmap\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"tickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"name\":\"ticks\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidityGross\",\"type\":\"uint128\"},{\"internalType\":\"int128\",\"name\":\"liquidityNet\",\"type\":\"int128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside0X128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside1X128\",\"type\":\"uint256\"},{\"internalType\":\"int56\",\"name\":\"tickCumulativeOutside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityOutsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsOutside\",\"type\":\"uint32\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token0\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token1\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"}]'
var abiFactory = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"FeeAmountEnabled\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"oldOwner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"newOwner\",\"type\":\"address\"}],\"name\":\"OwnerChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"name\":\"PoolCreated\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"tokenA\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"tokenB\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"}],\"name\":\"createPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"enableFeeAmount\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"feeAmountTickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"getPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"owner\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"parameters\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"factory\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_owner\",\"type\":\"address\"}],\"name\":\"setOwner\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]'

var contractV3FactoryAddress = "0x1F98431c8aD98523631AE4a59f267346ea31F984"
var contractV3SwapRouterV2Address = "0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45"

function main() {
    // ABI for registration of Uniswap factory contracts
    exchange.IO("abi", contractV3FactoryAddress, abiFactory)

    // Test the owner method of the Factory contract
    var owner = exchange.IO("api", contractV3FactoryAddress, "owner")
    Log("owner:", owner)   // The return value should be: 0x1a9C8182C09F50C8318d769245beA52c32BE35BC

    // Register ABI for Uniswap router contracts
    exchange.IO("abi", contractV3SwapRouterV2Address, abiRoute)

    // Factory method for testing Uniswap V3 Router V2 contracts
    var factoryOfRouter = exchange.IO("api", contractV3SwapRouterV2Address, "factory")
    Log("factoryOfRouter:", factoryOfRouter)  // The return value should be: 0x1F98431c8aD98523631AE4a59f267346ea31F984

    // Get the pool address of the trading pair
    var tokenIn = {name : "DAI", address: "0x6b175474e89094c44da98b954eedeac495271d0f"}
    var tokenOut = {name : "USDT", address: "0xdac17f958d2ee523a2206206994597c13d831ec7"}
    var poolAddress = exchange.IO("api", contractV3FactoryAddress, "getPool", tokenIn.address, tokenOut.address, 3000)
    var pair = "tokenIn:" + tokenIn.name + ", tokenOut:" + tokenOut.name + ", fee:" + 3000
    Log("Use the getPool method of the factory contract to get", pair, "pool address:", poolAddress)

    // Registration pool contract ABI
    exchange.IO("abi", poolAddress, abiPool)

    // Test pool contract
    var factoryOfPool = exchange.IO("api", poolAddress, "factory")
    Log("factoryOfPool:", factoryOfPool)   // The return value should be: 0x1F98431c8aD98523631AE4a59f267346ea31F984
}
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The above code registered the ABI of the factory contract, router contract and pool contract and did some tests. It can be observed that the factory method of both the router contract and the pool contract return the address 0x1F98431c8aD98523631AE4a59f267346ea31F984, which is the address of the Uniswap factory contract (variable contractV3FactoryAddress in the code).

var contractV3FactoryAddress = "0x1F98431c8aD98523631AE4a59f267346ea31F984"
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After registering the ABI of the smart contract, next we look at the exchange operation using Uniswap V3 first, and in the following we use the exchange of ERC20 tokens (on the Ethereum mainnet) as a specific scenario.

Query Uniswap V3 Router Contract Authorization

The allowance function is used in the ERC20 contract to query the number of tokens authorized to other addresses. It queries the number of tokens that a specific address has authorized to another address (usually the contract address) that can be transferred from its own account.
For Uniswap V3 router contracts, if you have already executed the approve function to authorize an address to a router contract, then you can use the allowance function of the ERC20 token to query the number of that authorization.

Remember the call to the ERC20 contract method we demonstrated in the previous tutorial? allowance and approve are both methods of the ERC20 contract, and these methods are on par with the balanceOf and transfer methods we explained before.

Before exchange, first we have to check if we have authorized enough tokens to the Uniswap router contract to perform the exchange, if the action we want to exchange is: 1INCH->ETH and the rate is set to 10000, which means the rate is 1%, the exchange pool of Uniswap may have multiple rates, generally several options are specified by Uniswap. For example, if the rate is set to 3000, it means the rate is 0.3%, please check the Uniswap documentation and related materials for details.

Note here that the actual exchange pool is 1INCH/WETH, and ETH and WETH are two different tokens in Ethereum.

  • ETH (Ethereum): ETH is the native cryptocurrency of the Ethereum blockchain and the primary asset and unit of computation of the Ethereum network. ETH is a native token on Ethereum with universal liquidity and usage for paying transaction fees, participating in smart contract interactions, storing value, etc.
  • WETH (Wrapped Ether): WETH is a form of ETH packaged as an ERC20 standard token. It is a smart contract on Ethereum designed to enable ETH to interact seamlessly with ERC20 tokens in a smart contract. WETH can be created and accessed by depositing ETH into the WETH contract address, and WETH can be transferred back to ETH at any time. The primary role of WETH in the Ethereum ecosystem is to provide ETH with the same standard interface and compatibility with other ERC20 tokens, enabling ETH to participate in decentralized transactions, liquidity pools and other DeFi protocols.

As such, WETH is a wrapper form of ETH that enables ETH to interact as an ERC20 token in an Ethereum smart contract. Typically, when ETH needs to be used in a smart contract, ETH can be converted to WETH, traded or involved in DeFi operations, and then WETH can be reconverted back to ETH as needed.

Use the allowance method of ERC20 to obtain the number of authorizations:

var abiRoute = '[{"inputs":[{"internalType":"address","name":"_factoryV2","type":"address"},{"internalType":"address","name":"factoryV3","type":"address"},{"internalType":"address","name":"_positionManager","type":"address"},{"internalType":"address","name":"_WETH9","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH9","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes","name":"data","type":"bytes"}],"name":"callPositionManager","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"paths","type":"bytes[]"},{"internalType":"uint128[]","name":"amounts","type":"uint128[]"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactInputParams","name":"params","type":"tuple"}],"name":"exactInput","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactInputSingleParams","name":"params","type":"tuple"}],"name":"exactInputSingle","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactOutputParams","name":"params","type":"tuple"}],"name":"exactOutput","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct 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\"amount\",\"type\":\"uint128\"}],\"name\":\"burn\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collect\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collectProtocol\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"factory\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"fee\",\"outputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal0X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal1X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"flash\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"}],\"name\":\"increaseObservationCardinalityNext\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"}],\"name\":\"initialize\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"liquidity\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"maxLiquidityPerTick\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"mint\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"name\":\"observations\",\"outputs\":[{\"internalType\":\"uint32\",\"name\":\"blockTimestamp\",\"type\":\"uint32\"},{\"internalType\":\"int56\",\"name\":\"tickCumulative\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityCumulativeX128\",\"type\":\"uint160\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint32[]\",\"name\":\"secondsAgos\",\"type\":\"uint32[]\"}],\"name\":\"observe\",\"outputs\":[{\"internalType\":\"int56[]\",\"name\":\"tickCumulatives\",\"type\":\"int56[]\"},{\"internalType\":\"uint160[]\",\"name\":\"secondsPerLiquidityCumulativeX128s\",\"type\":\"uint160[]\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"name\":\"positions\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside0LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside1LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"protocolFees\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"token0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"token1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint8\",\"name\":\"feeProtocol0\",\"type\":\"uint8\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol1\",\"type\":\"uint8\"}],\"name\":\"setFeeProtocol\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"slot0\",\"outputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"},{\"internalType\":\"uint16\",\"name\":\"observationIndex\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinality\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol\",\"type\":\"uint8\"},{\"internalType\":\"bool\",\"name\":\"unlocked\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"}],\"name\":\"snapshotCumulativesInside\",\"outputs\":[{\"internalType\":\"int56\",\"name\":\"tickCumulativeInside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityInsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsInside\",\"type\":\"uint32\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"bool\",\"name\":\"zeroForOne\",\"type\":\"bool\"},{\"internalType\":\"int256\",\"name\":\"amountSpecified\",\"type\":\"int256\"},{\"internalType\":\"uint160\",\"name\":\"sqrtPriceLimitX96\",\"type\":\"uint160\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"swap\",\"outputs\":[{\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int16\",\"name\":\"\",\"type\":\"int16\"}],\"name\":\"tickBitmap\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"tickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"name\":\"ticks\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidityGross\",\"type\":\"uint128\"},{\"internalType\":\"int128\",\"name\":\"liquidityNet\",\"type\":\"int128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside0X128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside1X128\",\"type\":\"uint256\"},{\"internalType\":\"int56\",\"name\":\"tickCumulativeOutside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityOutsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsOutside\",\"type\":\"uint32\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token0\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token1\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"}]'
var abiFactory = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"FeeAmountEnabled\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"oldOwner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"newOwner\",\"type\":\"address\"}],\"name\":\"OwnerChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"name\":\"PoolCreated\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"tokenA\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"tokenB\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"}],\"name\":\"createPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"enableFeeAmount\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"feeAmountTickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"getPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"owner\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"parameters\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"factory\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_owner\",\"type\":\"address\"}],\"name\":\"setOwner\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]'

var contractV3FactoryAddress = "0x1F98431c8aD98523631AE4a59f267346ea31F984"
var contractV3SwapRouterV2Address = "0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45"

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function main() {
    // ABI for registration of Uniswap factory contracts
    exchange.IO("abi", contractV3FactoryAddress, abiFactory)

    // Register ABI for Uniswap router contracts
    exchange.IO("abi", contractV3SwapRouterV2Address, abiRoute)

    // Get the pool address of the trading pair
    var tokenIn = {name : "1INCH", address: "0x111111111117dC0aa78b770fA6A738034120C302", decimals: exchange.IO("api", "0x111111111117dC0aa78b770fA6A738034120C302", "decimals")}
    var tokenOut = {name : "WETH", address: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", decimals: exchange.IO("api", "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", "decimals")}
    var poolAddress = exchange.IO("api", contractV3FactoryAddress, "getPool", tokenIn.address, tokenOut.address, 10000)

    // Registration pool contract ABI
    exchange.IO("abi", poolAddress, abiPool)

    // Get the current configured wallet address
    var walletAddress = exchange.IO("address")

    // 1INCH -> ETH, tokenIn: 1INCH
    var allowanceAmount = exchange.IO("api", tokenIn.address, "allowance", walletAddress, contractV3SwapRouterV2Address)
    Log("allowanceAmount:", allowanceAmount, ", use the toAmount() function to convert to readable values:", toAmount(allowanceAmount, tokenIn.decimals))
}
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We should be familiar with the function toAmount() in the code. We have used the custom function code several times in the previous chapters of the course for processing data into human-readable values.

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}
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Running the code, we find that the current number of authorizations is 0. Then we must authorize a sufficient number of router contracts to make an exchange.

Authorize Uniswap V3 Router Contract

If the number of authorizations is found to be insufficient after querying with allowance, it is necessary to authorize the Uniswap V3 routER contract with approve to allow it to operate a certain number of ERC20 tokens.

We still use the 1INCH -> ETH exchange as an example, use the approve method of ERC20 to give the Uniswap router contract authorization to operate the 1INCH tokens in the currently configured wallet.

var abiRoute = '[{"inputs":[{"internalType":"address","name":"_factoryV2","type":"address"},{"internalType":"address","name":"factoryV3","type":"address"},{"internalType":"address","name":"_positionManager","type":"address"},{"internalType":"address","name":"_WETH9","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH9","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes","name":"data","type":"bytes"}],"name":"callPositionManager","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"paths","type":"bytes[]"},{"internalType":"uint128[]","name":"amounts","type":"uint128[]"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactInputParams","name":"params","type":"tuple"}],"name":"exactInput","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactInputSingleParams","name":"params","type":"tuple"}],"name":"exactInputSingle","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactOutputParams","name":"params","type":"tuple"}],"name":"exactOutput","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactOutputSingleParams","name":"params","type":"tuple"}],"name":"exactOutputSingle","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"factory","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"factoryV2","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"getApprovalType","outputs":[{"internalType":"enum IApproveAndCall.ApprovalType","name":"","type":"uint8"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint256","name":"tokenId","type":"uint256"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"}],"internalType":"struct IApproveAndCall.IncreaseLiquidityParams","name":"params","type":"tuple"}],"name":"increaseLiquidity","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"int24","name":"tickLower","type":"int24"},{"internalType":"int24","name":"tickUpper","type":"int24"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"internalType":"struct IApproveAndCall.MintParams","name":"params","type":"tuple"}],"name":"mint","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes32","name":"previousBlockhash","type":"bytes32"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"results","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"positionManager","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"pull","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"refundETH","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermit","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowed","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowedIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapExactTokensForTokens","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMax","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapTokensForExactTokens","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"int256","name":"amount0Delta","type":"int256"},{"internalType":"int256","name":"amount1Delta","type":"int256"},{"internalType":"bytes","name":"_data","type":"bytes"}],"name":"uniswapV3SwapCallback","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"value","type":"uint256"}],"name":"wrapETH","outputs":[],"stateMutability":"payable","type":"function"},{"stateMutability":"payable","type":"receive"}]';
var abiPool = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"name\":\"Burn\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"name\":\"Collect\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"name\":\"CollectProtocol\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"paid0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"paid1\",\"type\":\"uint256\"}],\"name\":\"Flash\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint16\",\"name\":\"observationCardinalityNextOld\",\"type\":\"uint16\"},{\"indexed\":false,\"internalType\":\"uint16\",\"name\":\"observationCardinalityNextNew\",\"type\":\"uint16\"}],\"name\":\"IncreaseObservationCardinalityNext\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"}],\"name\":\"Initialize\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"name\":\"Mint\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol0Old\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol1Old\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol0New\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol1New\",\"type\":\"uint8\"}],\"name\":\"SetFeeProtocol\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"indexed\":false,\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"},{\"indexed\":false,\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"}],\"name\":\"Swap\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"}],\"name\":\"burn\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collect\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collectProtocol\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"factory\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"fee\",\"outputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal0X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal1X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"flash\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"}],\"name\":\"increaseObservationCardinalityNext\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"}],\"name\":\"initialize\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"liquidity\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"maxLiquidityPerTick\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"mint\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"name\":\"observations\",\"outputs\":[{\"internalType\":\"uint32\",\"name\":\"blockTimestamp\",\"type\":\"uint32\"},{\"internalType\":\"int56\",\"name\":\"tickCumulative\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityCumulativeX128\",\"type\":\"uint160\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint32[]\",\"name\":\"secondsAgos\",\"type\":\"uint32[]\"}],\"name\":\"observe\",\"outputs\":[{\"internalType\":\"int56[]\",\"name\":\"tickCumulatives\",\"type\":\"int56[]\"},{\"internalType\":\"uint160[]\",\"name\":\"secondsPerLiquidityCumulativeX128s\",\"type\":\"uint160[]\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"name\":\"positions\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside0LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside1LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"protocolFees\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"token0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"token1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint8\",\"name\":\"feeProtocol0\",\"type\":\"uint8\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol1\",\"type\":\"uint8\"}],\"name\":\"setFeeProtocol\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"slot0\",\"outputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"},{\"internalType\":\"uint16\",\"name\":\"observationIndex\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinality\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol\",\"type\":\"uint8\"},{\"internalType\":\"bool\",\"name\":\"unlocked\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"}],\"name\":\"snapshotCumulativesInside\",\"outputs\":[{\"internalType\":\"int56\",\"name\":\"tickCumulativeInside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityInsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsInside\",\"type\":\"uint32\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"bool\",\"name\":\"zeroForOne\",\"type\":\"bool\"},{\"internalType\":\"int256\",\"name\":\"amountSpecified\",\"type\":\"int256\"},{\"internalType\":\"uint160\",\"name\":\"sqrtPriceLimitX96\",\"type\":\"uint160\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"swap\",\"outputs\":[{\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int16\",\"name\":\"\",\"type\":\"int16\"}],\"name\":\"tickBitmap\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"tickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"name\":\"ticks\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidityGross\",\"type\":\"uint128\"},{\"internalType\":\"int128\",\"name\":\"liquidityNet\",\"type\":\"int128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside0X128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside1X128\",\"type\":\"uint256\"},{\"internalType\":\"int56\",\"name\":\"tickCumulativeOutside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityOutsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsOutside\",\"type\":\"uint32\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token0\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token1\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"}]'
var abiFactory = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"FeeAmountEnabled\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"oldOwner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"newOwner\",\"type\":\"address\"}],\"name\":\"OwnerChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"name\":\"PoolCreated\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"tokenA\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"tokenB\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"}],\"name\":\"createPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"enableFeeAmount\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"feeAmountTickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"getPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"owner\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"parameters\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"factory\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_owner\",\"type\":\"address\"}],\"name\":\"setOwner\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]'

var contractV3FactoryAddress = "0x1F98431c8aD98523631AE4a59f267346ea31F984"
var contractV3SwapRouterV2Address = "0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45"

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(n, decimals) {
    return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}

function main() {
    // ABI for registration of Uniswap factory contracts
    exchange.IO("abi", contractV3FactoryAddress, abiFactory)

    // Register ABI for Uniswap router contracts
    exchange.IO("abi", contractV3SwapRouterV2Address, abiRoute)

    // Get the pool address of the trading pair
    var tokenIn = {name : "1INCH", address: "0x111111111117dC0aa78b770fA6A738034120C302", decimals: exchange.IO("api", "0x111111111117dC0aa78b770fA6A738034120C302", "decimals")}
    var tokenOut = {name : "WETH", address: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", decimals: exchange.IO("api", "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", "decimals")}
    var poolAddress = exchange.IO("api", contractV3FactoryAddress, "getPool", tokenIn.address, tokenOut.address, 10000)

    // Registration pool contract ABI
    exchange.IO("abi", poolAddress, abiPool)

    // Get the current configured wallet address
    var walletAddress = exchange.IO("address")

    // 1INCH -> WETH, tokenIn: 1INCH
    var allowanceAmount = exchange.IO("api", tokenIn.address, "allowance", walletAddress, contractV3SwapRouterV2Address)
    Log("allowanceAmount:", allowanceAmount, ", Use the toAmount() function to convert to readable values:", toAmount(allowanceAmount, tokenIn.decimals))

    var balance = exchange.IO("api", "0x111111111117dC0aa78b770fA6A738034120C302", "balanceOf", walletAddress)
    var balanceOf1INCH = toAmount(balance, tokenIn.decimals)
    Log("balanceOf1INCH:", balanceOf1INCH)

    var swapAmount = 38
    if (balanceOf1INCH < swapAmount) {
        Log("In the wallet", tokenIn.name, "Insufficient, the number is only:", balanceOf1INCH)
    }

    if (toAmount(allowanceAmount, tokenIn.decimals) < swapAmount) {
        Log("Insufficient authorization quantity, proceed with authorization")
        // You can also specify an unlimited number of authorizations, i.e. replace the code toInnerAmount(swapAmount, tokenIn.decimals) with '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff'
        var txApprove = exchange.IO("api", tokenIn.address, "approve", contractV3SwapRouterV2Address, toInnerAmount(swapAmount, tokenIn.decimals))
        if (!txApprove) {
            Log("Authorization failed")
        } else {
            for (var i = 0; i < 10; i++) {
                Sleep(5000)
                var info = exchange.IO("api", "eth", "eth_getTransactionReceipt", txApprove)
                if (info && info.gasUsed) {
                    Log("info:", info)
                    break
                }
                Log('Transaction not yet mined', txApprove)
            }
            // Check the number of authorizations again
            allowanceAmount = exchange.IO("api", tokenIn.address, "allowance", walletAddress, contractV3SwapRouterV2Address)
            Log("Check the number of authorizations again,", "allowanceAmount:", allowanceAmount, ", use the toAmount() function to convert to readable values:", toAmount(allowanceAmount, tokenIn.decimals))
        }
    }
}
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Image description

The code adds a toInnerAmount() custom function implementation, this function is often used in our previous courses, so we will not repeat it here.
You can see the authorization record, call the code again to check the authorization status:

allowanceAmount = exchange.IO("api", tokenIn.address, "allowance", walletAddress, contractV3SwapRouterV2Address)
Log("Check the number of authorizations again,", "allowanceAmount:", allowanceAmount, ", use the toAmount() function to convert to readable values:", toAmount(allowanceAmount, tokenIn.decimals))
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Token Exchange Using Uniswap

When there are enough tokens in the wallet to be paid (i.e.: tokenIn), and the Uniswap router contract is authorized for a sufficient number of operations, the next step is to perform the exchange.
The Uniswap router contract has multiple exchange methods, here we demonstrate the use of the exactInput method, the actual exchange pool is 1INCH/WETH, and after the exchange, the unwrapWETH9 method is used to unwrap WETH into ETH. This concept we have explained in the previous ERC20 chapter withdraw description.

The exchange operation uses three main methods, namely exactInput, unwrapWETH9, and multicall. First, encode the call to the exactInput method of the Uniswap router contract, the call to the unwrapWETH9 method, and then batch execution using the multicall method of the router contract.

    // Exchange
    var recipientAddress = "0x0000000000000000000000000000000000000002"  // If the final exchange result is ETH or WETH, you need to specify the recipient parameter of the exactInput method as "0x0000000000000000000000000000000000000002"
    var fee = exchange.IO("encodePacked", "uint24", 10000)
    var path = tokenIn.address.slice(2).toLowerCase() + fee + tokenOut.address.slice(2).toLowerCase()
    var minOut = 1
    var amountIn = toInnerAmount(swapAmount, tokenIn.decimals)

    var swapToken = exchange.IO("encode", contractV3SwapRouterV2Address, "exactInput", {
        path: path,
        recipient: recipientAddress,
        amountIn: amountIn,
        amountOutMinimum: minOut
    })

    var data = [swapToken]
    data.push(exchange.IO("encode", contractV3SwapRouterV2Address, "unwrapWETH9(uint256,address)", 1, walletAddress))
    var tx = exchange.IO("api", contractV3SwapRouterV2Address, "multicall(uint256,bytes[])", 0, (new Date().getTime() / 1000) + 3600, data)
    Log("tx:", tx)
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  • Use the exchange.IO("encodePacked", ...) function to encode and compress the rate parameters.
  • Construct the path parameter path according to the parameter requirements of the exactInput method.
  • Use exchange.IO("encode", ...) function to encode the call to the exactInput method. Note: If the final exchange result is ETH or WETH, you need to specify the recipient parameter of the exactInput method as "0x0000000000000000000000000000000000000002"
  • Use exchange.IO("encode", ...) function encodes the unwrapWETH9(uint256,address) method call.
  • Use the multicall(uint256,bytes[]) method to execute the function call encoded above.

Retrieve exchange result:

Image description

Complete code:

var abiRoute = '[{"inputs":[{"internalType":"address","name":"_factoryV2","type":"address"},{"internalType":"address","name":"factoryV3","type":"address"},{"internalType":"address","name":"_positionManager","type":"address"},{"internalType":"address","name":"_WETH9","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH9","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes","name":"data","type":"bytes"}],"name":"callPositionManager","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"paths","type":"bytes[]"},{"internalType":"uint128[]","name":"amounts","type":"uint128[]"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactInputParams","name":"params","type":"tuple"}],"name":"exactInput","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactInputSingleParams","name":"params","type":"tuple"}],"name":"exactInputSingle","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactOutputParams","name":"params","type":"tuple"}],"name":"exactOutput","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactOutputSingleParams","name":"params","type":"tuple"}],"name":"exactOutputSingle","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"factory","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"factoryV2","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"getApprovalType","outputs":[{"internalType":"enum IApproveAndCall.ApprovalType","name":"","type":"uint8"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint256","name":"tokenId","type":"uint256"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"}],"internalType":"struct IApproveAndCall.IncreaseLiquidityParams","name":"params","type":"tuple"}],"name":"increaseLiquidity","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"int24","name":"tickLower","type":"int24"},{"internalType":"int24","name":"tickUpper","type":"int24"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"internalType":"struct IApproveAndCall.MintParams","name":"params","type":"tuple"}],"name":"mint","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes32","name":"previousBlockhash","type":"bytes32"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"results","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"positionManager","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"pull","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"refundETH","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermit","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowed","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowedIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapExactTokensForTokens","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMax","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapTokensForExactTokens","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"int256","name":"amount0Delta","type":"int256"},{"internalType":"int256","name":"amount1Delta","type":"int256"},{"internalType":"bytes","name":"_data","type":"bytes"}],"name":"uniswapV3SwapCallback","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"value","type":"uint256"}],"name":"wrapETH","outputs":[],"stateMutability":"payable","type":"function"},{"stateMutability":"payable","type":"receive"}]';
var abiPool = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"name\":\"Burn\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"name\":\"Collect\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"name\":\"CollectProtocol\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"paid0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"paid1\",\"type\":\"uint256\"}],\"name\":\"Flash\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint16\",\"name\":\"observationCardinalityNextOld\",\"type\":\"uint16\"},{\"indexed\":false,\"internalType\":\"uint16\",\"name\":\"observationCardinalityNextNew\",\"type\":\"uint16\"}],\"name\":\"IncreaseObservationCardinalityNext\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"}],\"name\":\"Initialize\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"name\":\"Mint\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol0Old\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol1Old\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol0New\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol1New\",\"type\":\"uint8\"}],\"name\":\"SetFeeProtocol\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"indexed\":false,\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"},{\"indexed\":false,\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"}],\"name\":\"Swap\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"}],\"name\":\"burn\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collect\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collectProtocol\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"factory\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"fee\",\"outputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal0X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal1X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"flash\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"}],\"name\":\"increaseObservationCardinalityNext\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"}],\"name\":\"initialize\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"liquidity\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"maxLiquidityPerTick\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"mint\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"name\":\"observations\",\"outputs\":[{\"internalType\":\"uint32\",\"name\":\"blockTimestamp\",\"type\":\"uint32\"},{\"internalType\":\"int56\",\"name\":\"tickCumulative\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityCumulativeX128\",\"type\":\"uint160\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint32[]\",\"name\":\"secondsAgos\",\"type\":\"uint32[]\"}],\"name\":\"observe\",\"outputs\":[{\"internalType\":\"int56[]\",\"name\":\"tickCumulatives\",\"type\":\"int56[]\"},{\"internalType\":\"uint160[]\",\"name\":\"secondsPerLiquidityCumulativeX128s\",\"type\":\"uint160[]\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"name\":\"positions\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside0LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside1LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"protocolFees\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"token0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"token1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint8\",\"name\":\"feeProtocol0\",\"type\":\"uint8\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol1\",\"type\":\"uint8\"}],\"name\":\"setFeeProtocol\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"slot0\",\"outputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"},{\"internalType\":\"uint16\",\"name\":\"observationIndex\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinality\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol\",\"type\":\"uint8\"},{\"internalType\":\"bool\",\"name\":\"unlocked\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"}],\"name\":\"snapshotCumulativesInside\",\"outputs\":[{\"internalType\":\"int56\",\"name\":\"tickCumulativeInside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityInsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsInside\",\"type\":\"uint32\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"bool\",\"name\":\"zeroForOne\",\"type\":\"bool\"},{\"internalType\":\"int256\",\"name\":\"amountSpecified\",\"type\":\"int256\"},{\"internalType\":\"uint160\",\"name\":\"sqrtPriceLimitX96\",\"type\":\"uint160\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"swap\",\"outputs\":[{\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int16\",\"name\":\"\",\"type\":\"int16\"}],\"name\":\"tickBitmap\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"tickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"name\":\"ticks\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidityGross\",\"type\":\"uint128\"},{\"internalType\":\"int128\",\"name\":\"liquidityNet\",\"type\":\"int128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside0X128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside1X128\",\"type\":\"uint256\"},{\"internalType\":\"int56\",\"name\":\"tickCumulativeOutside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityOutsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsOutside\",\"type\":\"uint32\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token0\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token1\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"}]'
var abiFactory = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"FeeAmountEnabled\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"oldOwner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"newOwner\",\"type\":\"address\"}],\"name\":\"OwnerChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"name\":\"PoolCreated\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"tokenA\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"tokenB\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"}],\"name\":\"createPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"enableFeeAmount\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"feeAmountTickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"getPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"owner\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"parameters\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"factory\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_owner\",\"type\":\"address\"}],\"name\":\"setOwner\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]'

var contractV3FactoryAddress = "0x1F98431c8aD98523631AE4a59f267346ea31F984"
var contractV3SwapRouterV2Address = "0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45"

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(n, decimals) {
    return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}

function main() {
    // ABI for registration of Uniswap factory contracts
    exchange.IO("abi", contractV3FactoryAddress, abiFactory)

    // Register ABI for Uniswap router contracts
    exchange.IO("abi", contractV3SwapRouterV2Address, abiRoute)

    // Get the pool address of the trading pair
    var tokenIn = {name : "1INCH", address: "0x111111111117dC0aa78b770fA6A738034120C302", decimals: exchange.IO("api", "0x111111111117dC0aa78b770fA6A738034120C302", "decimals")}
    var tokenOut = {name : "WETH", address: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", decimals: exchange.IO("api", "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", "decimals")}
    var poolAddress = exchange.IO("api", contractV3FactoryAddress, "getPool", tokenIn.address, tokenOut.address, 10000)

    // Registration pool contract ABI
    exchange.IO("abi", poolAddress, abiPool)

    // Get the current configured wallet address
    var walletAddress = exchange.IO("address")

    // 1INCH -> WETH, tokenIn: 1INCH
    var allowanceAmount = exchange.IO("api", tokenIn.address, "allowance", walletAddress, contractV3SwapRouterV2Address)
    Log("allowanceAmount:", allowanceAmount, ", use the toAmount() function to convert to readable values:", toAmount(allowanceAmount, tokenIn.decimals))

    var balance = exchange.IO("api", "0x111111111117dC0aa78b770fA6A738034120C302", "balanceOf", walletAddress)
    var balanceOf1INCH = toAmount(balance, tokenIn.decimals)
    Log("balanceOf1INCH:", balanceOf1INCH)

    var swapAmount = 38
    if (balanceOf1INCH < swapAmount) {
        Log("In the wallet", tokenIn.name, "insufficient, the number is only:", balanceOf1INCH)
    }

    if (toAmount(allowanceAmount, tokenIn.decimals) < swapAmount) {
        Log("Insufficient authorization quantity, proceed with authorization")
        // You can also specify an unlimited number of authorizations, i.e. replace the code toInnerAmount(swapAmount, tokenIn.decimals) with '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff'
        var txApprove = exchange.IO("api", tokenIn.address, "approve", contractV3SwapRouterV2Address, toInnerAmount(swapAmount, tokenIn.decimals))
        if (!txApprove) {
            Log("Authorization failed")
        } else {
            for (var i = 0; i < 10; i++) {
                Sleep(5000)
                var info = exchange.IO("api", "eth", "eth_getTransactionReceipt", txApprove)
                if (info && info.gasUsed) {
                    Log("info:", info)
                    break
                }
                Log('Transaction not yet mined', txApprove)
            }
            // Check the number of authorizations again
            allowanceAmount = exchange.IO("api", tokenIn.address, "allowance", walletAddress, contractV3SwapRouterV2Address)
            Log("Check the number of authorizations again,", "allowanceAmount:", allowanceAmount, ", use the toAmount() function to convert to readable values:", toAmount(allowanceAmount, tokenIn.decimals))
        }
    }

    // Exchange
    var recipientAddress = "0x0000000000000000000000000000000000000002"
    var fee = exchange.IO("encodePacked", "uint24", 10000)
    var path = tokenIn.address.slice(2).toLowerCase() + fee + tokenOut.address.slice(2).toLowerCase()
    var minOut = 1
    var amountIn = toInnerAmount(swapAmount, tokenIn.decimals)

    var swapToken = exchange.IO("encode", contractV3SwapRouterV2Address, "exactInput", {
        path: path,
        recipient: recipientAddress,
        amountIn: amountIn,
        amountOutMinimum: minOut
    })

    var data = [swapToken]
    data.push(exchange.IO("encode", contractV3SwapRouterV2Address, "unwrapWETH9(uint256,address)", 1, walletAddress))
    var tx = exchange.IO("api", contractV3SwapRouterV2Address, "multicall(uint256,bytes[])", 0, (new Date().getTime() / 1000) + 3600, data)
    Log("tx:", tx)
}
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Get the Exchange Price in the Pool

As we explained before, when we use the token address (there are two: tokenIn and tokenOut) and the rate setting, we can get the exchange pool (smart contract) address of this exchange portfolio from the getPool method of the Factory contract of Uniswap.
Once the pool address is obtained, the ABI of the pool contract is registered and the slot0 method of the pool contract can be called to get the data related to the current exchange price and further resolve the exchange price.

var abiRoute = '[{"inputs":[{"internalType":"address","name":"_factoryV2","type":"address"},{"internalType":"address","name":"factoryV3","type":"address"},{"internalType":"address","name":"_positionManager","type":"address"},{"internalType":"address","name":"_WETH9","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH9","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes","name":"data","type":"bytes"}],"name":"callPositionManager","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"paths","type":"bytes[]"},{"internalType":"uint128[]","name":"amounts","type":"uint128[]"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactInputParams","name":"params","type":"tuple"}],"name":"exactInput","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactInputSingleParams","name":"params","type":"tuple"}],"name":"exactInputSingle","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"}],"internalType":"struct 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\"amount\",\"type\":\"uint128\"}],\"name\":\"burn\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collect\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collectProtocol\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"factory\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"fee\",\"outputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal0X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal1X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"flash\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"}],\"name\":\"increaseObservationCardinalityNext\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"}],\"name\":\"initialize\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"liquidity\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"maxLiquidityPerTick\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"mint\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"name\":\"observations\",\"outputs\":[{\"internalType\":\"uint32\",\"name\":\"blockTimestamp\",\"type\":\"uint32\"},{\"internalType\":\"int56\",\"name\":\"tickCumulative\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityCumulativeX128\",\"type\":\"uint160\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint32[]\",\"name\":\"secondsAgos\",\"type\":\"uint32[]\"}],\"name\":\"observe\",\"outputs\":[{\"internalType\":\"int56[]\",\"name\":\"tickCumulatives\",\"type\":\"int56[]\"},{\"internalType\":\"uint160[]\",\"name\":\"secondsPerLiquidityCumulativeX128s\",\"type\":\"uint160[]\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"name\":\"positions\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside0LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside1LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"protocolFees\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"token0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"token1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint8\",\"name\":\"feeProtocol0\",\"type\":\"uint8\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol1\",\"type\":\"uint8\"}],\"name\":\"setFeeProtocol\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"slot0\",\"outputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"},{\"internalType\":\"uint16\",\"name\":\"observationIndex\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinality\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol\",\"type\":\"uint8\"},{\"internalType\":\"bool\",\"name\":\"unlocked\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"}],\"name\":\"snapshotCumulativesInside\",\"outputs\":[{\"internalType\":\"int56\",\"name\":\"tickCumulativeInside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityInsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsInside\",\"type\":\"uint32\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"bool\",\"name\":\"zeroForOne\",\"type\":\"bool\"},{\"internalType\":\"int256\",\"name\":\"amountSpecified\",\"type\":\"int256\"},{\"internalType\":\"uint160\",\"name\":\"sqrtPriceLimitX96\",\"type\":\"uint160\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"swap\",\"outputs\":[{\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int16\",\"name\":\"\",\"type\":\"int16\"}],\"name\":\"tickBitmap\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"tickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"name\":\"ticks\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidityGross\",\"type\":\"uint128\"},{\"internalType\":\"int128\",\"name\":\"liquidityNet\",\"type\":\"int128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside0X128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside1X128\",\"type\":\"uint256\"},{\"internalType\":\"int56\",\"name\":\"tickCumulativeOutside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityOutsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsOutside\",\"type\":\"uint32\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token0\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token1\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"}]'
var abiFactory = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"FeeAmountEnabled\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"oldOwner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"newOwner\",\"type\":\"address\"}],\"name\":\"OwnerChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"name\":\"PoolCreated\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"tokenA\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"tokenB\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"}],\"name\":\"createPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"enableFeeAmount\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"feeAmountTickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"getPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"owner\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"parameters\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"factory\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_owner\",\"type\":\"address\"}],\"name\":\"setOwner\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]'

var contractV3FactoryAddress = "0x1F98431c8aD98523631AE4a59f267346ea31F984"
var contractV3SwapRouterV2Address = "0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45"

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(n, decimals) {
    return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}

function main() {
    // ABI for registration of Uniswap factory contracts
    exchange.IO("abi", contractV3FactoryAddress, abiFactory)

    // Register ABI for Uniswap router contracts
    exchange.IO("abi", contractV3SwapRouterV2Address, abiRoute)

    // Get the pool address of the trading pair
    var tokenIn = {name : "1INCH", address: "0x111111111117dC0aa78b770fA6A738034120C302", decimals: exchange.IO("api", "0x111111111117dC0aa78b770fA6A738034120C302", "decimals")}
    var tokenOut = {name : "WETH", address: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", decimals: exchange.IO("api", "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", "decimals")}
    var poolAddress = exchange.IO("api", contractV3FactoryAddress, "getPool", tokenIn.address, tokenOut.address, 10000)

    // Registration pool contract ABI
    exchange.IO("abi", poolAddress, abiPool)

    var slot0 = exchange.IO("api", poolAddress, "slot0")
    Log("slot0:", slot0)
}
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Get the price information of the exchange pool and print out the slot0 variable in the code:

{
    "feeProtocol":0,
    "unlocked":true,
    "sqrtPriceX96":"1128983883551457130720648561",
    "tick":"-85025",
    "observationIndex":5,
    "observationCardinality":6,
    "observationCardinalityNext":6
}
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Where the main price information data is recorded in the sqrtPriceX96 field, it is necessary to calculate the current price of the exchange pool together according to the token accuracy data of the exchange portfolio, according to the description in the Uniswap document we implement a function to calculate:

function computePoolPrice(decimals0, decimals1, sqrtPriceX96) {
    // sqrtPriceX96 = sqrt(price) * 2^96
    [decimals0, decimals1, sqrtPriceX96] = [decimals0, decimals1, sqrtPriceX96].map(BigInt);
    const TWO = BigInt(2);
    const TEN = BigInt(10);
    const SIX_TENTH = BigInt(1000000);
    const Q192 = (TWO ** BigInt(96)) ** TWO;
    return (
        Number((sqrtPriceX96 ** TWO * TEN ** decimals0 * SIX_TENTH) / (Q192 * TEN ** decimals1)) /
        Number(SIX_TENTH)
    );
}
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Use this function to calculate the current price of the exchange pool with a token combination of 1INCH/WETH and a rate of 10000.

function computePoolPrice(decimals0, decimals1, sqrtPriceX96) {
    // sqrtPriceX96 = sqrt(price) * 2^96
    [decimals0, decimals1, sqrtPriceX96] = [decimals0, decimals1, sqrtPriceX96].map(BigInt);
    const TWO = BigInt(2);
    const TEN = BigInt(10);
    const SIX_TENTH = BigInt(1000000);
    const Q192 = (TWO ** BigInt(96)) ** TWO;
    return (
        Number((sqrtPriceX96 ** TWO * TEN ** decimals0 * SIX_TENTH) / (Q192 * TEN ** decimals1)) /
        Number(SIX_TENTH)
    );
}
function main() {
    var tokenIn = {name : "1INCH", address: "0x111111111117dC0aa78b770fA6A738034120C302", decimals: exchange.IO("api", "0x111111111117dC0aa78b770fA6A738034120C302", "decimals")}
    var tokenOut = {name : "WETH", address: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", decimals: exchange.IO("api", "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", "decimals")}

    // In the obtained slot0 variable "sqrtPriceX96":"1128983883551457130720648561",
    var price = computePoolPrice(tokenIn.decimals, tokenOut.decimals, "1128983883551457130720648561")
    Log("price:", price)
}
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Print the variable price to show: price: 0.000203 (1 1INCH for 0.000203 WETH).

Uniswap V3 Trading Class Library

The FMZ Quant Trading Platform has disclosed a packaged Uniswap template, which has been implemented to exchange, get prices, query wallet balance and other functions, without having to write code repeatedly based on the above explanation, you can read the source code of this template for more in-depth learning, development of Web3 direction applications.
The template class library has many details designed to learn:

  • Get the token information automatically An excerpt from one of the codes explains, when the parameter AutoFetchTokens of this template is set to true, the template program will automatically visit the https://tokens.coingecko.com/uniswap/all.json link to get and process all token information automatically. This eliminates the need to manually add a token in the strategy code (otherwise you would need to use addToken(name, address) to add the token). 
       if (AutoFetchTokens) {
            let res = JSON.parse(HttpQuery("https://tokens.coingecko.com/uniswap/all.json"))
            Log("fetch", res.tokens.length, "tokens from", res.name)
            res.tokens.forEach(function(token) {
                if (token.chainId == chainId && token.symbol != "WETH") {
                    self.tokenInfo[token.symbol] = {
                        name: token.symbol,
                        decimals: token.decimals,
                        address: token.address
                    }
                }
            })
        }
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  • Adaptation of different contract addresses according to chain settings The template sets ChainType parameter to support switching multiple chains: 
    'https://rpc.ankr.com/eth',
    'https://arb1.arbitrum.io/rpc',
    'https://mainnet.optimism.io/',
    'https://rpc.ankr.com/avalanche',
    'https://polygon-rpc.com',
    'https://rpc.ankr.com/celo',
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Excerpt code:

        if (typeof(ChainType) === 'number') {
            let chainRpc = [
                '',
                'https://rpc.ankr.com/eth',
                'https://arb1.arbitrum.io/rpc',
                'https://mainnet.optimism.io/',
                'https://rpc.ankr.com/avalanche',
                'https://polygon-rpc.com',
                'https://rpc.ankr.com/celo',
                //'https://mainnet.aurora.dev',
                //'https://bsc-dataseed.binance.org',
                //'https://exchainrpc.okex.org'
            ][ChainType]
            if (chainRpc && chainRpc.length > 0) {
                e.IO("base", chainRpc)
                Log("change base rpc to", chainRpc)
            }
        }
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Call Ethereum's RPC method eth_chainId to query the current chainId, and then adapt the WETH address, Uniswap a series of contract addresses, USDT contract addresses, etc. according to the chainId (a certain smart contract may have different contract addresses on different chains).

Excerpt code:

        // https://docs.uniswap.org/contracts/v3/reference/deployments
        let WETHAddress = {
            1: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2", // Ethereum
            3: "0xc778417E063141139Fce010982780140Aa0cD5Ab", // Ropsten
            4: "0xc778417E063141139Fce010982780140Aa0cD5Ab", // Rinkeby
            5: "0xB4FBF271143F4FBf7B91A5ded31805e42b2208d6", // Goerli
            42: "0xd0A1E359811322d97991E03f863a0C30C2cF029C", // Kovan
            10: "0x4200000000000000000000000000000000000006", // Optimism
            69: "0x4200000000000000000000000000000000000006", // Optimistic Kovan
            42161: "0x82aF49447D8a07e3bd95BD0d56f35241523fBab1", // Arbitrum One
            421611: "0xB47e6A5f8b33b3F17603C83a0535A9dcD7E32681", // Arbitrum Rinkeby
            137: "0x0d500B1d8E8eF31E21C99d1Db9A6444d3ADf1270", // Polygon
            80001: "0x9c3C9283D3e44854697Cd22D3Faa240Cfb032889", // Polygon Mumbai
        }

        let chainId = e.IO("api", "ETH", "eth_chainId")
        if (chainId) {
            chainId = Number(chainId)
            Log("chainId: ", chainId)
            let addr = WETHAddress[chainId]
            if (addr) {
                Log("Register WETH address", addr)
                self.addToken("ETH", addr)
            }
            if (chainId == 42220) {
                // Celo Address
                ContractV3Factory = '0xAfE208a311B21f13EF87E33A90049fC17A7acDEc'
                ContractV3SwapRouterV2 = '0x5615CDAb10dc425a742d643d949a7F474C01abc4'
                self.addToken('CELO', '0x471ece3750da237f93b8e339c536989b8978a438')
            } else if (chainId == 42161) {
                self.addToken('USDT', '0xfd086bc7cd5c481dcc9c85ebe478a1c0b69fcbb9')
            }
        } else {
            panic("get chain Id error")
        }
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  • Use the "Uniswap V3 Trading Library"

The $.testUniswap() function in this template is a function that tests the functionality of the template, and its code gives an example of how to use the template call:

  $.testUniswap = function() {
      let ex = $.NewUniswapV3()
      Log("walletAddress: ", ex.walletAddress)
      let tokenAddressMap = {
          "USDT": "0xdac17f958d2ee523a2206206994597c13d831ec7",
          "1INCH": "0x111111111117dC0aa78b770fA6A738034120C302",
          "USDC": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
          "DAI": "0x6b175474e89094c44da98b954eedeac495271d0f",
      }
      for (let name in tokenAddressMap) {
          ex.addToken(name, tokenAddressMap[name])
      }

      Log(ex.getPrice('ETH_USDT'))
      Log(ex.getPrice('1INCH_USDT'))

      // swap 0.01 ETH to USDT
      Log(ex.swapToken('ETH', 0.01, 'USDT'))
      let usdtBalance = ex.balanceOf('USDT')
      Log("balance of USDT", usdtBalance)

      // swap USDT to DAI then DAI to ETH
      Log(ex.swapToken('USDT', usdtBalance, 'DAI,ETH'))

      Log("balance of ETH", ex.getETHBalance())

      // Log(ex.sendETH('0x11111', 0.02))

      // ...
  }
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When a strategy references the "Uniswap V3 Trading Class Library" (see the FMZ platform documentation for how to reference the template class library), you can call the functions encapsulated in this template class library.

Create a variable named ex and call the interface function $.NewUniswapV3() that is wrapped in the "Uniswap V3 Trading Library" template to create an object to assign to ex.

let ex = $.NewUniswapV3()
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Use the member function addToken() of the ex object to add (register) token information.

    let tokenAddressMap = {
        "USDT": "0xdac17f958d2ee523a2206206994597c13d831ec7",
        "1INCH": "0x111111111117dC0aa78b770fA6A738034120C302",
        "USDC": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
        "DAI": "0x6b175474e89094c44da98b954eedeac495271d0f",
    }
    for (let name in tokenAddressMap) {
        ex.addToken(name, tokenAddressMap[name])
    }
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To get and print the exchange pool price for a particular trading pair, you can use the member function getPrice() of the ex object, which can be written as follows:

    Log(ex.getPrice('ETH_USDT'))
    Log(ex.getPrice('1INCH_USDT'))
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To perform the exchange operation, you can use the member function swapToken() of the ex object to perform the exchange:

    // swap 0.01 ETH to USDT
    Log(ex.swapToken('ETH', 0.01, 'USDT'))
    let usdtBalance = ex.balanceOf('USDT')
    Log("balance of USDT", usdtBalance)

    // swap USDT to DAI then DAI to ETH
    Log(ex.swapToken('USDT', usdtBalance, 'DAI,ETH'))
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Retrieving Events

In this section, we will learn to read events released by smart contracts using the FMZ Quant Trading Platform. The events released by smart contracts are stored in the logs of the Ethereum virtual machine.

eth_getLogs

To query the event of smart contract release, you need to use Ethereum's RPC method eth_getLogs to get the on-chain log data, for how to call Ethereum RPC nodes, we have explained in our previous course.
For example, we get the event of WETH contract can write code and test it using FMZ's debugging tool, the RPC node configured by the exchange object is an Ethereum mainnet node, and in calling the eth_getLogs method, we specify three parameters fromBlock, toBlock, address, and we use the fromBlock and toBlock parameters to limit the query to data within a block:

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}
function toInnerAmount(n, decimals) {
    return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}
function main() {
    // getBlockNumber
    var blockNumber = exchange.IO("api", "eth", "eth_blockNumber")
    Log("blockNumber:", blockNumber)

    // get logs
    var fromBlock = "0x" + (toAmount(blockNumber, 0) - 1).toString(16)
    var toBlock = "0x" + toAmount(blockNumber, 0).toString(16)
    var params = {
        "fromBlock" : fromBlock,
        "toBlock" : toBlock,
        "address" : "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2"   // Address of WETH contract
    }
    var logs = exchange.IO("api", "eth", "eth_getLogs", params)

    // Due to the large amount of data, if you use the Log function to print, the data will be truncated. Use return to return the complete data in the "Function Result" edit box on the page
    return logs   
}
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The logs data were obtained, and we omitted some of them due to their large content:

[{
    "data": "0x00000000000000000000000000000000000000000000000001c1a55000000000",
    "topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef", "0x0000000000000000000000006b75d8af000000e20b7a7ddf000ba900b4009a80", "0x000000000000000000000000bcb095c1f9c3dc02e834976706c87dee5d0f1fb6"],
    "transactionHash": "0x27f9bf5abe3148169b4b85a83e1de32bd50eb81ecc52e5af006157d93353e4c4",
    "transactionIndex": "0x0",
    "removed": false,
    "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
    "blockHash": "0x847be24a7b159c292bda030a011dfec89487b70e71eed486969b032d6ef04bad",
    "blockNumber": "0x109b1cc",
    "logIndex": "0x0"
}, {
    "data": "0x00000000000000000000000000000000000000000000000008ea20cdea027c00",
    "logIndex": "0x5",
    "topics": ["0xe1fffcc4923d04b559f4d29a8bfc6cda04eb5b0d3c460751c2402c5c5cc9109c", "0x0000000000000000000000007a250d5630b4cf539739df2c5dacb4c659f2488d"],
    "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
    "blockHash": "0x847be24a7b159c292bda030a011dfec89487b70e71eed486969b032d6ef04bad",
    "blockNumber": "0x109b1cc",
    "removed": false,
    "transactionHash": "0xace3afa02e8af5d1ef6fc1635fbdf7bee37624547937ea5272c23968dd034c09",
    "transactionIndex": "0x1"
},

...

{
    "blockNumber": "0x109b1cd",
    "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
    "data": "0x00000000000000000000000000000000000000000000000002c053531ab8a000",
    "logIndex": "0xd3",
    "removed": false,
    "topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef", "0x0000000000000000000000001111111254eeb25477b68fb85ed929f73a960582", "0x000000000000000000000000252ba9b5916171dbdadd2cec7f91875a006955d0"],
    "transactionHash": "0x3012b82891f85b077cfe1c12cb9722b93c696ef2c37d67981ccddcc9c3396aca",
    "transactionIndex": "0x8d",
    "blockHash": "0xcd3d567c9bd02a4549b1de0dc638ab5523e847c3c156b096424f56c633000fd9"
}, {
    "topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef", "0x00000000000000000000000012b791bb27b3a4ee958b5a435fea7d49ec076e9c", "0x000000000000000000000000ef1c6e67703c7bd7107eed8303fbe6ec2554bf6b"],
    "transactionIndex": "0x91",
    "logIndex": "0xdb",
    "removed": false,
    "blockNumber": "0x109b1cd",
    "data": "0x0000000000000000000000000000000000000000000000000164f2434262e1cc",
    "transactionHash": "0x6aa8d80daf42f442591e7530e31323d05e1d6dd9f9f9b9c102e157d89810c048",
    "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
    "blockHash": "0xcd3d567c9bd02a4549b1de0dc638ab5523e847c3c156b096424f56c633000fd9"
}, {
    "address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
    "blockHash": "0xcd3d567c9bd02a4549b1de0dc638ab5523e847c3c156b096424f56c633000fd9",
    "blockNumber": "0x109b1cd",
    "logIndex": "0xde",
    "removed": false,
    "topics": ["0x7fcf532c15f0a6db0bd6d0e038bea71d30d808c7d98cb3bf7268a95bf5081b65", "0x000000000000000000000000ef1c6e67703c7bd7107eed8303fbe6ec2554bf6b"],
    "data": "0x0000000000000000000000000000000000000000000000000164f2434262e1cc",
    "transactionHash": "0x6aa8d80daf42f442591e7530e31323d05e1d6dd9f9f9b9c102e157d89810c048",
    "transactionIndex": "0x91"
}]
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We can see that there are various events in the logs data, if we only care about Transfer events, we need to filter out the Transfer events in these data.

Retrieving Logs

The Ethereum log is divided into two parts: 1. topics; 2. data.

  • topics Taking the results of the code run for the eth_getLogs section test as an example, the data in the topics field is: 
  "topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef", "0x00000000000000000000000012b791bb27b3a4ee958b5a435fea7d49ec076e9c", "0x000000000000000000000000ef1c6e67703c7bd7107eed8303fbe6ec2554bf6b"],
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The value of the topics field is an array structure used to describe the event. It is specified that its (array) length cannot exceed 4 and the first element is the signature hash of the event.
In the FMZ Quant Trading Platform, we can calculate this signature hash using the Encode function, using the following code:

  function main() {
      var eventFunction = "Transfer(address,address,uint256)"
      var eventHash = Encode("keccak256", "string", "hex", eventFunction)
      Log("eventHash:", "0x" + eventHash)
      // eventHash: 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef
  }
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Calculate the keccak256 hash value (hex encoding) of Transfer(address,address,uint256) is 0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef.

The value of the topics field is an array structure, with the second element, and the third element, respectively:

  • Sending address from
  • Receiving address to 
    • data  The data in the data field are: 
  "data": "0x0000000000000000000000000000000000000000000000000164f2434262e1cc",
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Certain parameters in the event (parameters without indexed declarations in the Solidity code of the smart contract) are stored in the data section.

Parse the data 0x0000000000000000000000000000000000000000000000000164f2434262e1cc

  function toAmount(s, decimals) {
      return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
  }

  function main() {
      var value = "0x0000000000000000000000000000000000000000000000000164f2434262e1cc"
      Log(toAmount(value, 0) / 1e18)  // 0.10047146239950075
  }
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This data is obtained as 0.10047146239950075 and the data is the corresponding transfer amount.

The above was explained, practiced and ready to go. We can start retrieving the logs at:

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}
function toInnerAmount(n, decimals) {
    return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}
function main() {
    // getBlockNumber
    var blockNumber = exchange.IO("api", "eth", "eth_blockNumber")
    Log("blockNumber:", blockNumber)

    // get logs
    var fromBlock = "0x" + (toAmount(blockNumber, 0) - 1).toString(16)
    var toBlock = "0x" + toAmount(blockNumber, 0).toString(16)
    var params = {
        "fromBlock" : fromBlock,
        "toBlock" : toBlock,
        "address" : "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2"
    }
    var logs = exchange.IO("api", "eth", "eth_getLogs", params)

    // Traverse logs
    var eventFunction = "Transfer(address,address,uint256)"
    var eventHash = "0x" + Encode("keccak256", "string", "hex", eventFunction)
    Log("eventHash:", eventHash)

    var counter = 0
    for (var i = logs.length - 1; i >= 0 && counter < 10; i--) {
        if (logs[i].topics[0] == eventHash) {
            Log("Event Transfer, data:", toAmount(logs[i].data, 0) / 1e18, ", blockNumber:", toAmount(logs[i].blockNumber, 0), ", transactionHash:", logs[i].transactionHash,
              ", log:", logs[i])
            counter++
        }
    }
}
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Check on https://etherscan.io/:

Image description

Results of the test code run in FMZ debugging tool:

Image description

Data in the from, to fields can also be parsed depending on the needs at the time of retrieving, e.g:

function main() {
    var from = "0x00000000000000000000000012b791bb27b3a4ee958b5a435fea7d49ec076e9c"
    var address = "0x" + exchange.IO("encodePacked", "address", from)
    Log("address:", address)
}
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Running results:

address: 0x12b791bb27b3a4ee958b5a435fea7d49ec076e9c

Listening to Contract Events

Since the debugging tool can only test the code for a short time and output the content only after the code execution is completed, it cannot display and output the log in real time. In this section, we use the FMZ Quant Trading Platform to create live trading to test.

Here we use the Ethereum mainnet, and we listen to the Transfer(address,address,uint256) event of the USDT cryptocurrency contract. Based on what we learned in the last lesson, we designed and wrote an example of continuously listening to the events of a certain smart contract:

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(n, decimals) {
    return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}

function addEventListener(contractAddress, event, callBack) {
    var self = {}
    self.eventHash = "0x" + Encode("keccak256", "string", "hex", event)
    self.contractAddress = contractAddress
    self.latestBlockNumber = 0
    self.fromBlockNumber = 0
    self.firstBlockNumber = 0
    /* TODO: test
    self.isFirst = true 
    */ 

    self.getBlockNumber = function() {
        var maxTry = 10
        for (var i = 0; i < maxTry; i++) {
            var ret = exchange.IO("api", "eth", "eth_blockNumber")
            if (ret) {
                return toAmount(ret, 0)
            }
            Sleep(5000)
        }
        throw "getBlockNumber failed"
    }

    self.run = function() {
        var currBlockNumber = self.getBlockNumber()
        var fromBlock = "0x" + self.fromBlockNumber.toString(16)
        var toBlock = "0x" + currBlockNumber.toString(16)
        var params = {
            "fromBlock" : fromBlock, 
            "toBlock" : toBlock, 
            "address" : self.contractAddress, 
            "topics" : [self.eventHash]
        }
        // Log("fromBlockNumber:", self.fromBlockNumber, ", currBlockNumber:", currBlockNumber, "#FF0000")

        var logs = exchange.IO("api", "eth", "eth_getLogs", params)
        if (!logs) {
            return 
        }

        for (var i = 0; i < logs.length; i++) {
            if (toAmount(logs[i].blockNumber, 0) > self.latestBlockNumber) {
                /* TODO: test
                if (self.isFirst) {
                    self.firstBlockNumber = toAmount(logs[i].blockNumber, 0)
                    Log("firstBlockNumber:", self.firstBlockNumber)
                    self.isFirst = false 
                }
                */

                callBack(logs[i])
            }
        }

        self.latestBlockNumber = currBlockNumber
        self.fromBlockNumber = self.latestBlockNumber - 1
    }

    self.latestBlockNumber = self.getBlockNumber()
    self.fromBlockNumber = self.latestBlockNumber - 1

    return self
}

var listener = null 
function main() {
    var event = "Transfer(address,address,uint256)"
    var contractAddress = "0xdac17f958d2ee523a2206206994597c13d831ec7"
    var decimals = exchange.IO("api", contractAddress, "decimals")
    Log(exchange.IO("api", contractAddress, "name"), " decimals:", decimals)

    listener = addEventListener(contractAddress, event, function(log) {        
        var fromAddress = "0x" + exchange.IO("encodePacked", "address", log.topics[1])
        var toAddress = "0x" + exchange.IO("encodePacked", "address", log.topics[2])
        Log("Transfer:", fromAddress, "->", toAddress, ", value:", toAmount(log.data, decimals), ", blockNumber:", toAmount(log.blockNumber, 0))

        /* TODO: test
        arrLog.push(log)
        */
    })

    while (true) {
        listener.run()
        Sleep(5000)
    }
}

/* TODO: test
var arrLog = []
function onexit() {
    Log("End the run and verify the record")
    var firstBlockNumber = listener.firstBlockNumber
    var endBlockNumber = listener.latestBlockNumber

    Log("getLogs, from:", firstBlockNumber, " -> to:", endBlockNumber)
    var fromBlock = "0x" + (firstBlockNumber).toString(16)
    var toBlock = "0x" + (endBlockNumber).toString(16)
    var params = {
        "fromBlock" : fromBlock,
        "toBlock" : toBlock,
        "topics" : ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef"],
        "address" : "0xdac17f958d2ee523a2206206994597c13d831ec7"
    }
    var logs = exchange.IO("api", "eth", "eth_getLogs", params)

    Log("arrLog:", arrLog.length)
    Log("logs:", logs.length)

    if (arrLog.length != logs.length) {
        Log("Length varies!")
        return 
    }

    for (var i = 0; i < arrLog.length; i++) {
        Log("Determine the blockNumber:", logs[i].blockNumber == arrLog[i].blockNumber, ", Determine from:", logs[i].topics[1] == arrLog[i].topics[1], 
            "Determine to:", logs[i].topics[2] == arrLog[i].topics[2])
    }
}
*/
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Running on live trading:

Image description

For the execution results, a validation section (TODO: test) is also written in the code. After a simple validation it can be seen that the Transfer event of the USDT contract is continuously monitored and data is recorded, and a comparison between this data and the event data obtained at once can be observed that the data is consistent with:

Image description

Event Filtering

Based on the previous lesson Listening to contract events, we expand on it by adding filters to the listening process to listen for transfers to and from specified addresses. When a smart contract creates a log (i.e. releases an event), the log data topics contains up to 4 pieces of information. So we design a filter rule with [[A1, A2, ...An], null, [C1], D] as an example.

  1. [A1, A2, ...An] corresponds to the data at position topics[0].
  2. Null corresponds to the data at position topics[1].
  3. [C1] corresponds to data at position topics[2].
  4. D corresponds to the data at position topics[3].
  • If an element in the condition structure is set null means it is not filtered, e.g. null corresponds to topics[1] and any value matches.
  • If the element in the condition structure sets a single value indicating that the position must match, e.g. [C1] corresponds to topics[2] or D corresponds to topics[3], and unmatched logs are filtered.
  • If the element in the condition structure is an array, it means that at least one of the elements in the array should match, e.g. [A1, A2, ...An] corresponds to topics[0], [A1, A2, ...An] with any one of them matching `topics[0], then the logs will not be filtered.

Listening to USDT transfers from exchanges

Monitoring of USDT transactions transferred from and to the Binance Exchange:

`
function toAmount(s, decimals) {
return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(n, decimals) {
return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}

function addEventListener(contractAddress, event, callBack) {
var self = {}
self.eventHash = "0x" + Encode("keccak256", "string", "hex", event)
self.contractAddress = contractAddress
self.latestBlockNumber = 0
self.fromBlockNumber = 0
self.firstBlockNumber = 0
self.filters = []

self.setFilter = function(filterCondition) {
    if (filterCondition.length > 4) {
        throw "filterCondition error"
    }

    self.filters.push(filterCondition)
    Log("Set filter conditions:", filterCondition)
}

self.getTokenBalanceOfWallet = function(walletAddress, tokenAddress, tokenDecimals) {
    var balance = exchange.IO("api", tokenAddress, "balanceOf", walletAddress)
    if (balance) {
        return toAmount(balance, tokenDecimals)
    }
    return null
}

self.getBlockNumber = function() {
    var maxTry = 10
    for (var i = 0; i < maxTry; i++) {
        var ret = exchange.IO("api", "eth", "eth_blockNumber")
        if (ret) {
            return toAmount(ret, 0)
        }
        Sleep(5000)
    }
    throw "getBlockNumber failed"
}

self.run = function() {
    var currBlockNumber = self.getBlockNumber()
    var fromBlock = "0x" + self.fromBlockNumber.toString(16)
    var toBlock = "0x" + currBlockNumber.toString(16)
    var params = {
        "fromBlock" : fromBlock, 
        "toBlock" : toBlock, 
        "address" : self.contractAddress, 
        "topics" : [self.eventHash]
    }

    var logs = exchange.IO("api", "eth", "eth_getLogs", params)
    if (!logs) {
        return 
    }

    for (var i = 0; i < logs.length; i++) {
        if (toAmount(logs[i].blockNumber, 0) > self.latestBlockNumber) {
            // Check the filter condition, and execute the judgment if the filter condition is set
            if (self.filters.length != 0) {
                // Initial filter marker
                var isFilter = true 
                // Traverse filter condition setting
                for (var j = 0; j < self.filters.length; j++) {
                    // Take a filter setting, e.g: [[A1, A2, ...An], null, [C1], D]
                    var cond = self.filters[j]

                    // Traverse the filter setting
                    var final = true
                    for (var topicsIndex = 0; topicsIndex < cond.length; topicsIndex++) {
                        // Take one of the conditions in the filter setting, if it is the first condition: i.e. the data to be compared with topics[0]
                        var condValue = cond[topicsIndex]

                        // Data in the logs
                        if (topicsIndex > logs[i].topics.length - 1) {
                            continue 
                        }
                        var topicsEleValue = logs[i].topics[topicsIndex]
                        // If it's a Transfer event, you need to handle the from and to
                        if (logs[i].topics[0] == "0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef") {
                            if (topicsIndex == 1 || topicsIndex == 2) {
                                topicsEleValue = "0x" + exchange.IO("encodePacked", "address", topicsEleValue)
                            }
                        }

                        // If the condValue type is an array, it means that there are multiple comparison conditions in this position, and the multiple condition comparison is a logical or relationship
                        if (Array.isArray(condValue) && condValue.length > 1) {
                            // Determine condValue[0] == topicsEleValue || condValue[1] == topicsEleValue
                            final = final && condValue.some(element => element === topicsEleValue)
                        }else if (condValue === null) {
                            final = final && true
                        } else {
                            final = final && (condValue === topicsEleValue)
                        }
                    }

                    if (final) {
                        isFilter = false 
                    }
                }

                if (isFilter) {
                    continue
                }
            }
            callBack(logs[i])
        }
    }

    self.latestBlockNumber = currBlockNumber
    self.fromBlockNumber = self.latestBlockNumber - 1
}

self.latestBlockNumber = self.getBlockNumber()
self.fromBlockNumber = self.latestBlockNumber - 1

return self
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}

var listener = null
function main() {
// Initial clean-up log
LogReset(1)
LogProfitReset()

var event = "Transfer(address,address,uint256)"                          // Listening to events
var contractAddress = "0xdac17f958d2ee523a2206206994597c13d831ec7"       // USDT contract address
var decimals = exchange.IO("api", contractAddress, "decimals")           // Get the precision information of USDT token
var accountBinanceAddress = "0x28C6c06298d514Db089934071355E5743bf21d60" // Binance hot wallet address
accountBinanceAddress = accountBinanceAddress.toLowerCase()              // Addresses are handled in lowercase
Log(exchange.IO("api", contractAddress, "name"), " decimals:", decimals)

// Creating a listener object
listener = addEventListener(contractAddress, event, function(log) {
    var fromAddress = "0x" + exchange.IO("encodePacked", "address", log.topics[1])
    var toAddress = "0x" + exchange.IO("encodePacked", "address", log.topics[2])
    if (fromAddress == accountBinanceAddress) {
        Log("Binance transfer out - ", " Transfer:", fromAddress, "->", toAddress, ", value:", toAmount(log.data, decimals), ", blockNumber:", toAmount(log.blockNumber, 0), "#CD32CD")
    } else if (toAddress == accountBinanceAddress) {
        Log("Binance transfer in - ", " Transfer:", fromAddress, "->", toAddress, ", value:", toAmount(log.data, decimals), ", blockNumber:", toAmount(log.blockNumber, 0), "#FF0000")
    }        
})

// Set up event filtering
listener.setFilter([null, accountBinanceAddress, null])   // Binance -> USDT
listener.setFilter([null, null, accountBinanceAddress])   // USDT -> Binance

var preBalance = 0
while (true) {
    listener.run()
    var balance = listener.getTokenBalanceOfWallet(accountBinanceAddress, contractAddress, decimals)
    if (balance) {
        var direction = ""
        if (preBalance != 0 && preBalance > balance) {
            direction = " ↓ " + (preBalance - balance) + "#CD32CD"
        } else if (preBalance != 0 && preBalance < balance) {
            direction = " ↑ " + (balance - preBalance) + "#FF0000"
        }
        Log("Binance wallet address:", accountBinanceAddress, " balance:", balance, direction)
        LogProfit(balance, "&")   // Drawing only, no log printing
        preBalance = balance
    }
    LogStatus(_D(), "Binance wallet address:", accountBinanceAddress, ", balance:", balance)
    Sleep(5000 * 3)
}
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}
`

The above code running in live trading:

Image description

In this lesson, we introduced how to design an event filter. And used it to listen for USDT transactions associated with the Binance Exchange hot wallet. You can modify and extend this sample program to listen to any event you are interested in, to see what new transactions smart money has made, what new items the NFT Tycoons have rushed, etc.

Unit conversions

Many of the calculations related to Ethereum have values that exceed the maximum safe integer of the JavaScript language. Therefore, some methods are needed on the FMZ Quant Trading Platform to handle large values, which we have used specifically in previous courses and have not covered in detail. This section will discuss this aspect in detail.

Print the maximum safe integer defined in the JavaScript language:

javascript
function main() {
Log("Number.MAX_SAFE_INTEGER:", Number.MAX_SAFE_INTEGER)
}

Running results:

Number.MAX_SAFE_INTEGER: 9007199254740991

BigInt

The smallest unit defined in Ethereum is 1wei, and the definition 1Gwei is equal to 1000000000 wei. 1Gwei is not really a very large number in Ethereum-related calculations, and some data is much larger than it. So these data with very large values can easily exceed Number.MAX_SAFE_INTEGER: 9007199254740991.

At FMZ Quant Trading Platform, we use the platform's BigInt object to represent these very large integer data. Use the constructor BigInt() to construct the BigInt object. You can construct BigInt objects using numeric, hexadecimal numeric strings as parameters. Use the toString() method of BigInt object to output the data represented by the object as a string.

The operations supported by the BigInt object are:

  • Addition: +
  • Subtraction: -
  • Multiplication: *
  • Division: /
  • Modulo operations: %
  • Power operations: *

Refer to the following code examples:

`javascript
function main() {
// Decimal representation of 1Gwei
var oneGwei = 1000000000

// Decimal to hexadecimal conversion of 1Gwei
var oneGweiForHex = "0x" + oneGwei.toString(16)

Log("oneGwei : ", oneGwei)
Log("oneGweiForHex : ", oneGweiForHex)

// Constructing BigInt objects
Log("1Gwei / 1Gwei : ", (BigInt(oneGwei) / BigInt(oneGweiForHex)).toString(10))
Log("1Gwei * 1Gwei : ", (BigInt(oneGwei) * BigInt(oneGweiForHex)).toString(10))
Log("1Gwei - 1Gwei : ", (BigInt(oneGwei) - BigInt(oneGweiForHex)).toString(10))
Log("1Gwei + 1Gwei : ", (BigInt(oneGwei) + BigInt(oneGweiForHex)).toString(10))
Log("(1Gwei + 1) % 1Gwei : ", (BigInt(oneGwei + 1) % BigInt(oneGweiForHex)).toString(10))
Log("1Gwei ** 2 : ", (BigInt(oneGwei) ** BigInt(2)).toString(10))
Log("The square root of 100 : ", (BigInt(100) ** BigFloat(0.5)).toString(10))

Log("Number.MAX_SAFE_INTEGER : ", BigInt(Number.MAX_SAFE_INTEGER).toString(10))
Log("Number.MAX_SAFE_INTEGER * 2 : ", (BigInt(Number.MAX_SAFE_INTEGER) * BigInt("2")).toString(10))
Enter fullscreen mode Exit fullscreen mode

}
`

Debugging tool testing:

run
2023-06-08 11:39:50 Info Number.MAX_SAFE_INTEGER * 2 : 18014398509481982
2023-06-08 11:39:50 Info Number.MAX_SAFE_INTEGER : 9007199254740991
2023-06-08 11:39:50 Info The square root of 100 : 10
2023-06-08 11:39:50 Info 1Gwei ** 2 : 1000000000000000000
2023-06-08 11:39:50 Info (1Gwei + 1) % 1Gwei : 1
2023-06-08 11:39:50 Info 1Gwei + 1Gwei : 2000000000
2023-06-08 11:39:50 Info 1Gwei - 1Gwei : 0
2023-06-08 11:39:50 Info 1Gwei * 1Gwei : 1000000000000000000
2023-06-08 11:39:50 Info 1Gwei / 1Gwei : 1
2023-06-08 11:39:50 Info oneGweiForHex : 0x3b9aca00
2023-06-08 11:39:50 Info oneGwei : 1000000000

BigFloat

The BigFloat object is used similarly to the BigInt object to represent floating point numbers with larger values, and it also supports addition, subtraction, multiplication and division.
The BigFloat object supports the toFixed() method.

Refer to the following code example:

`javascript
function main() {
var pi = 3.14
var oneGwei = "1000000000"
var oneGweiForHex = "0x3b9aca00"

Log("pi + oneGwei : ", (BigFloat(pi) + BigFloat(oneGwei)).toFixed(2))
Log("pi - oneGweiForHex : ", (BigFloat(pi) - BigFloat(oneGweiForHex)).toFixed(2))
Log("pi * 2.0 : ", (BigFloat(pi) * BigFloat(2.0)).toFixed(2))
Log("pi / 2.0 : ", (BigFloat(pi) / BigFloat(2.0)).toFixed(2))
Enter fullscreen mode Exit fullscreen mode

}
`

Debugging tool testing:

javascript
2023-06-08 13:56:44 Info pi / 2.0 : 1.57
2023-06-08 13:56:44 Info pi * 2.0 : 6.28
2023-06-08 13:56:44 Info pi - oneGweiForHex : -999999996.86
2023-06-08 13:56:44 Info pi + oneGwei : 1000000003.14

BigDecimal

The BigDecimal object is compatible with integer values and floating point values, and supports initialization with the BigInt object and the BigFloat object, and it also supports addition, subtraction, multiplication and division.

Refer to the following code example:

`javascript
function main() {
var pi = 3.1415
var oneGwei = 1000000000
var oneGweiForHex = "0x3b9aca00"

Log("pi : ", BigDecimal(pi).toFixed(2))
Log("oneGwei : ", BigDecimal(oneGwei).toString())
Log("oneGweiForHex : ", BigDecimal(BigInt(oneGweiForHex)).toString())

Log("BigInt(oneGwei) : ", BigDecimal(BigInt(oneGwei)).toString())    
Log("BigFloat(pi) : ", BigDecimal(BigFloat(pi)).toFixed(4))

Log("oneGwei + pi : ", (BigDecimal(oneGwei) + BigDecimal(pi)).toString())
Log("oneGwei - pi : ", (BigDecimal(oneGwei) - BigDecimal(pi)).toString())
Log("2.0 * pi : ", (BigDecimal(2.0) * BigDecimal(pi)).toString())
Log("pi / pi : ", (BigDecimal(pi) / BigDecimal(pi)).toString())
Enter fullscreen mode Exit fullscreen mode

}
`

Running in the debugging tool:

run
2023-06-08 14:52:53 Info pi / pi : 1
2023-06-08 14:52:53 Info 2.0 * pi : 6.283
2023-06-08 14:52:53 Info oneGwei - pi : 999999996.8585
2023-06-08 14:52:53 Info oneGwei + pi : 1000000003.1415
2023-06-08 14:52:53 Info BigFloat(pi) : 3.1415
2023-06-08 14:52:53 Info BigInt(oneGwei) : 1e+9
2023-06-08 14:52:53 Info oneGweiForHex : 1e+9
2023-06-08 14:52:53 Info oneGwei : 1e+9
2023-06-08 14:52:53 Info pi : 3.14

Unit conversions

The following two functions: toAmount(), toInnerAmount() we have used many times in previous courses, these two functions are mainly used for data precision conversion.

`
function toAmount(s, decimals) {
return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(n, decimals) {
return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}
`

The toAmount() function converts (reduces) a variable s according to the precision parameter decimals. In web3 practical development, it is often necessary to deal with some chained hexadecimal data.
We have often encountered this in our previous courses, for example, the data field data in the Transfer(address,address,uint256) event of a smart contract:

desc
{
"data": "0x00000000000000000000000000000000000000000000000001c1a55000000000",
"topics": ["0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef", "0x0000000000000000000000006b75d8af000000e20b7a7ddf000ba900b4009a80", "0x000000000000000000000000bcb095c1f9c3dc02e834976706c87dee5d0f1fb6"],
"transactionHash": "0x27f9bf5abe3148169b4b85a83e1de32bd50eb81ecc52e5af006157d93353e4c4",
"transactionIndex": "0x0",
"removed": false,
"address": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
"blockHash": "0x847be24a7b159c292bda030a011dfec89487b70e71eed486969b032d6ef04bad",
"blockNumber": "0x109b1cc",
"logIndex": "0x0"
}

When processing data "data": "0x00000000000000000000000000000000000000000000000001c1a55000000000", we use the toAmount() function. This processing is designed to do a good job of converting data field data to readable values.

`javascript
function toAmount(s, decimals) {
return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}

function main() {
var data = "0x00000000000000000000000000000000000000000000000001c1a55000000000"
Log(toAmount(data, 18)) // Print out 0.12656402755905127
}
`

1 ETH token, as we know, is 1e18 wei, if we get a data 126564027559051260 in wei, how to convert it to ETH tokens?
Using the toAmount(, 18) function is a very simple conversion method. The toInnerAmount() function is the reverse operation of the toAmount() function (depending on the precision, zoom in), and it is easy to convert the data using these two functions.

It is important to note the integer value safety range in the JavaScript language, Number.MAX_SAFE_INTEGER, and the following example illustrates a hidden problem when converting data:

`javascript
function toAmount(s, decimals) {
return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}
function toInnerAmount(n, decimals) {
return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}
function main() {
var amount = 0.01
var innerAmount = Number(toInnerAmount(amount, 18)) 

Log("Number.MAX_SAFE_INTEGER:", Number.MAX_SAFE_INTEGER)  // 9007199254740991
Log("innerAmount:", innerAmount)                          // 10000000000000000

Log("typeof(innerAmount):", typeof(innerAmount), ", innerAmount:", innerAmount)

// Decimal value 10000000000000000 -> Hexadecimal value 0x2386f26fc10000
Log("Convert", innerAmount, "to hexadecimal:", innerAmount.toString(16))
Log("Convert", BigInt(10000000000000000).toString(10), "to hexadecimal:", BigInt(10000000000000000).toString(16))

Log("0x" + BigInt(10000000000000000).toString(16), "Convert to decimal:", toAmount("0x" + BigInt(10000000000000000).toString(16), 0))
Enter fullscreen mode Exit fullscreen mode

}
`

It is possible to run in the debugging tool:

run
2023-06-15 16:21:40 Info Convert 0x2386f26fc10000 to decimal: 10000000000000000
2023-06-15 16:21:40 Info Convert 10000000000000000 to hexadecimal: 2386f26fc10000
2023-06-15 16:21:40 Info Convert 10000000000000000 to hexadecimal: 10000000000000000
2023-06-15 16:21:40 Info typeof(innerAmount): number , innerAmount: 10000000000000000
2023-06-15 16:21:40 Info innerAmount: 10000000000000000
2023-06-15 16:21:40 Info Number.MAX_SAFE_INTEGER: 9007199254740991

Through observation we found that:

javascript
Log("Convert", innerAmount, "to hexadecimal:", innerAmount.toString(16))

This line of code corresponds to the log output: Converting 10000000000000000 to hex: 10000000000000000, which is not converted correctly. The reason is naturally that 10000000000000000 is beyond Number.MAX_SAFE_INTEGER.

But when the decimal value is within the safe range, i.e., less than Number.MAX_SAFE_INTEGER, the toString(16) function converts it properly again, for example:

javascript
function main() {
var value = 1000
Log("Convert value to hexadecimal:", "0x" + value.toString(16)) // 0x3e8
Log("Convert 0x3e8 to decimal:", Number("0x3e8")) // 1000
}

In blockchain, even 0.01 ETH converted to a value of 10000000000000000 in wei will exceed Number.MAX_SAFE_INTEGER, so a safer conversion for such cases is: BigInt(10000000000000000).toString(16).

Simulation Calls

Executing transactions and calling the Write method of smart contracts on Ethereum costs a certain amount of gas and sometimes it fails. It is important to know which transactions are likely to fail before sending them and calling them. There are simulated calls on Ethereum for testing.

eth_call

Ethereum's RPC method eth_call: it can simulate a transaction and return the result of a possible transaction, but it does not actually execute the transaction on the blockchain.

The eth_call method has 2 parameters, the first one is a dictionary structure, transactionObject:

javascript
// transactionObject
{
"from" : ..., // The address from which the transaction is sent
"to" : ..., // The address to which the transaction is addressed
"gas" : ..., // The integer of gas provided for the transaction execution
"gasPrice" : ..., // The integer of gasPrice used for each paid gas encoded as hexadecimal
"value" : ..., // The integer of value sent with this transaction encoded as hexadecimal
"data" : ..., // The hash of the method signature and encoded parameters. For more information, see the Contract ABI description in the Solidity documentation
}

The second parameter is blockNumber: you can pass the label latest/pending/earliest, etc:

javascript
/* blockNumber
The block number in hexadecimal format or the string latest, earliest, pending, safe or
finalized (safe and finalized tags are only supported on Ethereum, Gnosis, Arbitrum,
Arbitrum Nova and Avalanche C-chain), see the default block parameter description in
the official Ethereum documentation
*/

Next, we take the smart contract method approve and transfer calls of the token DAI as an example for simulation calls, and the following test environment is the main Ethereum network.

Simulation call approve

We are all familiar with the approve method for ERC20 contracts, and we have practiced it in previous courses. Since the ERC20 contract is already built into the FMZ platform ABI, there is no need to register the ABI of the smart contract to be called by the simulation.

`javascript
function main() {
var contractAddressUniswapV3SwapRouterV2 = "0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45"
var contractAddress_DAI = "0x6b175474e89094c44da98b954eedeac495271d0f"
var wallet = exchange.IO("address")

// encode approve
var data = exchange.IO("encode", contractAddress_DAI, "approve(address,uint256)", 
    contractAddressUniswapV3SwapRouterV2, "0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff")
Log("ERC20 token DAI approve encode, data:", data)

var transactionObject = {
    "from" : wallet,
    "to" : contractAddress_DAI,
    // "gasPrice" : "0x" + parseInt("21270894680").toString(16),
    // "gas" : "0x" + parseInt("21000").toString(16),
    "data" : "0x" + data,
}
var blockNumber = "latest"

var ret = exchange.IO("api", "eth", "eth_call", transactionObject, blockNumber)
Log("ret:", ret)
Enter fullscreen mode Exit fullscreen mode

}
`

The code in the example first encodes the approve(address,uint256) method and parameters, and the parameter value 0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff of the approve method indicates the maximum number of authorizations. Authorization is given to the smart contract at address 0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45 i.e. the router contract for Uniswap V3. Finally the Ethereum RPC method eth_call is called for simulation. You can see that the gasPrice and gas fields in the transactionObject parameters can be omitted.

The debugging tool is run and the simulation calls the approve method to authorize successfully (it does not authorize actually):

run
2023-06-09 11:58:39 Info ret: 0x0000000000000000000000000000000000000000000000000000000000000001
2023-06-09 11:58:39 Info ERC20 token DAI approve encode, data: 095ea7b300000000000000000000000068b3465833fb72a70ecdf485e0e4c7bd8665fc45ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff

It is also possible to simulate some failure scenarios, when we adjust the gasPrice and gas parameters, if the ETH in the wallet is not enough to pay the gas fee, an error will be reported::

insufficient funds

When the gas cost is set too low, an error will be reported:

intrinsic gas too low: have 21000, want 21944 (supplied gas 21000)

Simulation call transfer

We are familiar with ERC20's transfer method, which allows you to transfer ERC20 tokens to a certain wallet address, so let's try to simulate a transfer of 1000 DAI to Vitalik Buterin.

`javascript
function toInnerAmount(n, decimals) {
return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}
function main() {
var walletVitalik = "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
var contractAddress_DAI = "0x6b175474e89094c44da98b954eedeac495271d0f"
var wallet = exchange.IO("address")

// transfer to Vitalik Buterin
var decimals_DAI = exchange.IO("api", contractAddress_DAI, "decimals")
var transferAmount = toInnerAmount(1000, decimals_DAI)
Log("Transfer amount:", 1000, "DAI, use toInnerAmount convert to:", transferAmount)

// encode transfer
var data = exchange.IO("encode", contractAddress_DAI, "transfer(address,uint256)",
    walletVitalik, transferAmount)

var transactionObject = {
    "from" : wallet,
    "to" : contractAddress_DAI,
    "data" : "0x" + data,
}
var blockNumber = "latest"

var ret = exchange.IO("api", "eth", "eth_call", transactionObject, blockNumber)
return ret
Enter fullscreen mode Exit fullscreen mode

}
`

Since I don't have DAI tokens in this test wallet, running it in the debug tool reported the following error unexpectedly:

execution reverted: Dai/insufficient-balance

Check the wallet address of Vitalik Buterin: 0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045, it is clear that this wallet has DAI tokens. So let's adjust the transfer direction of the simulation call and simulate the transfer of 1000 DAI from Vitalik Buterin to us.

Modify the code, where the changes I made comments:

`javascript
function toInnerAmount(n, decimals) {
return (BigDecimal(n) * BigDecimal(Math.pow(10, decimals))).toFixed(0)
}
function main() {
var walletVitalik = "0xd8dA6BF26964aF9D7eEd9e03E53415D37aA96045"
var contractAddress_DAI = "0x6b175474e89094c44da98b954eedeac495271d0f"
var wallet = exchange.IO("address")

var decimals_DAI = exchange.IO("api", contractAddress_DAI, "decimals")
var transferAmount = toInnerAmount(1000, decimals_DAI)
Log("Transfer amount:", 1000, "DAI, use toInnerAmount convert to:", transferAmount)

// encode transfer
var data = exchange.IO("encode", contractAddress_DAI, "transfer(address,uint256)",
    wallet, transferAmount)     // Use the wallet variable as a parameter and change the transfer recipient's address to my own

var transactionObject = {
    "from" : walletVitalik,     // Use the walletVitalik variable as the value of the from field to simulate that the call was made from the Vitalik Buterin's wallet address
    "to" : contractAddress_DAI,
    "data" : "0x" + data,
}
var blockNumber = "latest"

var ret = exchange.IO("api", "eth", "eth_call", transactionObject, blockNumber)
Log(ret)
Enter fullscreen mode Exit fullscreen mode

}
`

Debugging tool test:

javascript
2023-06-09 13:34:31 Info 0x0000000000000000000000000000000000000000000000000000000000000001
2023-06-09 13:34:31 Info Transfer amount: 1000 DAI, use toInnerAmount convert to: 1000000000000000000000

Using the FMZ Quant Trading Platform, it is easy to simulate the results of transactions and avoid unnecessary loss of gas fees from sending potentially failed transactions. We used the example code from this chapter of the course to simulate the call to transfer money to Vitalik Buterin's wallet and Vitalik Buterin's wallet to transfer money to us. Of course, there are many more uses for this eth_call method. Use your imagination, what would you use the eth_call method for?

Identify ERC721 Contracts

We know that tokens like ETH and BTC are homogenized tokens, and the token in your wallet is not different from the token in my wallet. But there are many things in the world that are not homogeneous, such as real estate, antiques, virtual artwork, etc. These cannot be represented by homogeneous tokens in abstraction. Therefore, there is the ERC721 standard to abstract non-homogeneous objects, and there is NFT and related concepts.
So among the many smart contracts deployed on Ethereum, how do we identify which smart contracts are ERC721 standard smart contracts?

To identify ERC721, it is important to know the ERC165 standard first.

ERC165

With the ERC165 standard, a smart contract can declare the interfaces it supports for other contracts to check. An ERC165 interface contract has only one function: supportsInterface(bytes4 interfaceId), the parameter interfaceId is the interface Id to be queried. If the contract implements the interfaceId returns a boolean true value, otherwise it returns a false value.

Here we are going to talk about how this interfaceId is calculated and encoded specifically.

ERC165 Standard shows an example:

`solidity
pragma solidity ^0.4.20;

interface Solidity101 {
function hello() external pure;
function world(int) external pure;
}

contract Selector {
function calculateSelector() public pure returns (bytes4) {
Solidity101 i;
return i.hello.selector ^ i.world.selector;
}
}
`

For the function signature of the interface (consisting of a function name and a list of parameter types) to perform a dissimilarity operation, for an ERC165 interface contract where the contract has only one function:

`solidity
pragma solidity ^0.4.20;

interface ERC165 {
/// @notice Query if a contract implements an interface
/// @param interfaceID The interface identifier, as specified in ERC-165
/// @dev Interface identification is specified in ERC-165. This function
/// uses less than 30,000 gas.
/// @return true if the contract implements interfaceID and
/// interfaceID is not 0xffffffff, false otherwise
function supportsInterface(bytes4 interfaceID) external view returns (bool);
}
`

The interface identifier for this interface is 0x01ffc9a7. You can calculate this by running bytes4(keccak256('supportsInterface(bytes4)')); or using the Selector contract above.

Calculate the function signature directly and take its first 4 bytes to arrive at interfaceId.

javascript
function main() {
var ret = Encode("keccak256", "string", "hex", "supportsInterface(bytes4)")
Log("supportsInterface(bytes4) interfaceId:", "0x" + ret.slice(0, 8))
}

Tests can be run in the debug tool at:

run
2023-06-13 14:53:35 Info supportsInterface(bytes4) interfaceId: 0x01ffc9a7

It can be seen that the calculated results are consistent with the description in the ERC165 Standard document.

ERC721

Next let's look at the interface definition of the ERC721 contract standard:

`solidity
interface ERC721 /* is ERC165 */ {
event Transfer(address indexed _from, address indexed _to, uint256 indexed _tokenId);

event Approval(address indexed _owner, address indexed _approved, uint256 indexed _tokenId);

event ApprovalForAll(address indexed _owner, address indexed _operator, bool _approved);

function balanceOf(address _owner) external view returns (uint256);

function ownerOf(uint256 _tokenId) external view returns (address);

function safeTransferFrom(address _from, address _to, uint256 _tokenId, bytes data) external payable;

function safeTransferFrom(address _from, address _to, uint256 _tokenId) external payable;

function transferFrom(address _from, address _to, uint256 _tokenId) external payable;

function approve(address _approved, uint256 _tokenId) external payable;

function setApprovalForAll(address _operator, bool _approved) external;

function getApproved(uint256 _tokenId) external view returns (address);

function isApprovedForAll(address _owner, address _operator) external view returns (bool);
Enter fullscreen mode Exit fullscreen mode

}
`

If we want to determine whether a smart contract is an ERC721 contract, first we need to know the interfaceId of the ERC721 contract before we can try to use the supportsInterface(bytes4 interfaceId) method to determine it. In previous courses, we have familiarized us with some concepts of the ERC165 standard and the algorithm for calculating the interfaceId, and we write code to calculate directly:

`javascript
function calcSelector(arrSelector) {
var ret = null
if (Array.isArray(arrSelector)) {
if (arrSelector.length == 1) {
ret = Encode("keccak256", "string", "hex", arrSelector[0])
} else if (arrSelector.length == 0) {
throw "Error: the number of elements in the array is 0"
} else {
var viewEncodeData = null
for (var i = 0; i < arrSelector.length; i++) {
if (i == 0) {
ret = new Uint8Array(Encode("keccak256", "string", "raw", arrSelector[i]))
} else {
viewData = new Uint8Array(Encode("keccak256", "string", "raw", arrSelector[i]))

                if (viewData.length != ret.length) {
                    throw "Error: TypeArray view length is different"
                }

                for (var index = 0; index < ret.length; index++) {
                    ret[index] ^= viewData[index]
                }
            }
        }
        ret = Encode("raw", "raw", "hex", ret.buffer)
    }
} else {
    throw "Error: The parameter requires an array type."
}

return "0x" + ret.slice(0, 8)
Enter fullscreen mode Exit fullscreen mode

}
function main() {
// supportsInterface(bytes4): 0x01ffc9a7
// var ret = calcSelector(["supportsInterface(bytes4)"])

// ERC721Metadata: 0x5b5e139f
/* 
var arrSelector = [
    "name()",
    "symbol()",
    "tokenURI(uint256)"
]
var ret = calcSelector(arrSelector)
*/

// ERC721: 0x80ac58cd
// /*
var arrSelector = [
    "balanceOf(address)",
    "ownerOf(uint256)",
    "safeTransferFrom(address,address,uint256,bytes)",
    "safeTransferFrom(address,address,uint256)",
    "transferFrom(address,address,uint256)",
    "approve(address,uint256)",
    "setApprovalForAll(address,bool)",
    "getApproved(uint256)",
    "isApprovedForAll(address,address)",
]
var ret = calcSelector(arrSelector)
// */

Log(ret)
Enter fullscreen mode Exit fullscreen mode

}
`

The code uses the Encode() function for function signature calculation (the keccak256 algorithm), and for the calculation in the code example above, specifying the output parameter of the Encode() function as "raw", the function returns the ArrayBuffer type of JavaScript language.
To perform a ^ (iso-or) operation on two ArrayBuffer objects, you need to create a TypedArray view based on the ArrayBuffer object, then iterate through the data in it and perform the iso-or operation one by one.

Run in the debugging tool:

run
2023-06-13 15:04:09 Info 0x80ac58cd

It can be seen that the calculated results are consistent with those described in eip-721.

`solidity
pragma solidity ^0.4.20;

/// @title ERC-721 Non-Fungible Token Standard/// @dev See https://eips.ethereum.org/EIPS/eip-721/// Note: the ERC-165 identifier for this interface is 0x80ac58cd.interface ERC721 /* is ERC165 */ {
/// @dev This emits when ownership of any NFT changes by any mechanism.
/// This event emits when NFTs are created (from == 0) and destroyed
/// (to == 0). Exception: during contract creation, any number of NFTs
/// may be created and assigned without emitting Transfer. At the time of
/// any transfer, the approved address for that NFT (if any) is reset to none.
event Transfer(address indexed _from, address indexed _to, uint256 indexed _tokenId);
...

`

With the ERC721 interface Id, we can determine if a contract is an ERC721 standard contract or not. We use BAYC to do the test, which is a contract that follows ERC721. First we need to register the ABI, and since we only call the following three methods, we can register these three methods:

  • supportsInterface(interfaceId)
  • symbol()
  • name()

The specific codes are as follows:

`javascript
function main() {
// Contract address for ERC721, BAYC is used here
var testContractAddress = "0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d"

var testABI = `[{
    "inputs": [{
        "internalType": "bytes4",
        "name": "interfaceId",
        "type": "bytes4"
    }],
    "name": "supportsInterface",
    "outputs": [{
        "internalType": "bool",
        "name": "",
        "type": "bool"
    }],
    "stateMutability": "view",
    "type": "function"
}, {
    "inputs": [],
    "name": "symbol",
    "outputs": [{
        "internalType": "string",
        "name": "",
        "type": "string"
    }],
    "stateMutability": "view",
    "type": "function"
}, {
    "inputs": [],
    "name": "name",
    "outputs": [{
        "internalType": "string",
        "name": "",
        "type": "string"
    }],
    "stateMutability": "view",
    "type": "function"
}]`

// ERC721 Interface Id, calculated in the previous course
var interfaceId = "0x80ac58cd"

// Register ABI
exchange.IO("abi", testContractAddress, testABI)

// Call the supportsInterface method
var isErc721 = exchange.IO("api", testContractAddress, "supportsInterface", interfaceId)

// Output Information
Log("Contract address:", testContractAddress)
Log("Contract name:", exchange.IO("api", testContractAddress, "name"))
Log("Contract code:", exchange.IO("api", testContractAddress, "symbol"))
Log("Whether the contract is ERC721 standard:", isErc721)
Enter fullscreen mode Exit fullscreen mode

}
`

Tests can be run in the debugging tool:

run
2023-06-13 16:32:57 Info Whether the contract is ERC721 standard: true
2023-06-13 16:32:57 Info Contract code: BAYC
2023-06-13 16:32:57 Info Contract name: BoredApeYachtClub
2023-06-13 16:32:57 Info Contract address: 0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d

The contract with the address 0xbc4ca0eda7647a8ab7c2061c2e118a18a936f13d is determined to be ERC721 standard.

In this part, we introduced how to determine ERC721 contracts, so contracts like ERC20, which do not support the ERC165 standard, will have to be identified in another way. Do you know how to check if a contract is ERC20 standard?

Encoding calldata

What is calldata? By the author's understanding, a simple layman's description here is:

The "calldata" is the encoding of a function call or parameter in Ethereum, and the "calldata" is encoded according to the ABI (Application Binary Interface) specification of the contract.

For example, we can encode the balanceOf and transfer method calls of the ERC20 contract we studied in the previous course, together with the parameters of the calls, into a calldata. In some application scenarios, such as interaction between contracts, this scenario will use calldata, and of course there are many other application scenarios that are not listed here.

How to code a smart contract function call to get calldata?

In the FMZ Quant Trading Platform, you can use exchange.IO("encode", ...) to encode smart contract function calls, the use of exchange.IO("encode", ...) is very simple. The first parameter of the function is the fixed string "encode"; the second parameter is the address of the smart contract; the third parameter is the name of the smart contract method to be encoded; the rest of the parameters are passed to the specific parameter value of the smart contract method to be encoded.

eth_sendRawTransaction

When we encode a smart contract method call and generate the corresponding calldata data, if this smart contract method is a Write method (i.e.: write operation), we need to use the generated calldata data as the data field of the transaction and then use the Ethereum RPC method eth_ sendRawTransaction to send a request containing the raw data of that transaction to the Ethereum network.

The eth_sendRawTransaction method has only one parameter, data:

data: The signed transaction (typically signed with a library, using your private key)

The data parameter is a transaction data after the signature calculation, and the transaction data structure of Ethereum has the following main fields:

javascript
{
"nonce": "0x1", // Number of transactions on the account of the sender of the transaction
"gasPrice": "0x12a05f200", // Traded Gas price
"gasLimit": "0x5208", // Gas limit for trading
"to": "0xAb8483F64d9C6d1EcF9b849Ae677dD3315835cb2", // Target contract address or recipient address
"value": "0x4563918244F40000", // Number of Ethereum transferred
"data": "0x0123456789ABCDEF", // Data to send to the contract
}

How to sign an Ethereum transaction?

In the FMZ Quant Trading Platform, we use the Encode() function to perform the signature calculation, the specific example we write in the subsequent course "Execute Write method calldata".

Execute Read method calldata

For the execution of the calldata of the Read method, we use the previously learned RPC method: eth_call to execute it. We explained the eth_call RPC method of the Ethereum only did a demonstration of the Write method of the smart contract, in this section, we use the calldata method to demonstrate the execution of the smart contract Read method call. Let's use the balanceOf method of the WETH contract to read the current balance of WETH tokens in the wallet.

We use the debugging tool to test on the Ethereum mainnet at:

javascript
function toAmount(s, decimals) {
return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}
function main() {
// ABI for WETH contracts
var abiWETH =[{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"guy","type":"address"},{"name":"wad","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"wad","type":"uint256"}],"name":"withdraw","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"deposit","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"},{"name":"","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"guy","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Withdrawal","type":"event"}]`

// WETH contract address
var wethAddress = "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"

// Register ABI for WETH contracts
exchange.IO("abi", wethAddress, abiWETH)

// The wallet address of the currently configured exchange object
var walletAddress = exchange.IO("address")

// Coded WETH contract's deposit method call
var calldataForDeposit = exchange.IO("encode", wethAddress, "balanceOf(address)", walletAddress)
Log("calldataForDeposit:", "0x" + calldataForDeposit)

// Construct the transaction as the first parameter of eth_call
var transaction = {
    "from" : walletAddress,
    "to" : wethAddress,
    "data" : "0x" + calldataForDeposit,
}

// The second parameter of eth_call
var blockNumber = "latest"

// Call with eth_call
var ret = exchange.IO("api", "eth", "eth_call", transaction, blockNumber)
var wethBalance = exchange.IO("decode", "uint256", ret)   // You can use exchange.IO("decode", ...) function to decode
Log("wethBalance:", toAmount(wethBalance, 18))            // Converted from wei to WETH units
Enter fullscreen mode Exit fullscreen mode

}
`

Run in the debugging tool:

run
2023-06-15 11:51:31 Info wethBalance: 0.015
2023-06-15 11:51:31 Info calldataForDeposit: 0x70a082310000000000000000000000006b3f11d807809b0b1e5e3243df04a280d9f94bf4

If the method of a smart contract has a return value, you can use the exchange.IO("decode", ...) function to decode it. You can see that the passing calldata method is the same as calling the smart contract's balanceOf method directly, getting the WETH balance of 0.015 WETH for my test wallet.

Execute Write method calldata

For the execution of the Write method calldata, it is necessary to use the RPC method: eth_sendRawTransaction.

Let's use the debugging tool and test it on the Ethereum mainnet at:

javascript
function toAmount(s, decimals) {
return Number((BigDecimal(BigInt(s)) / BigDecimal(Math.pow(10, decimals))).toString())
}
function toInnerAmount(s, decimals) {
return (BigDecimal(s)*BigDecimal(Math.pow(10, decimals))).toFixed(0)
}
function main() {
// ABI for WETH contracts
var abiWETH =[{"constant":true,"inputs":[],"name":"name","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"guy","type":"address"},{"name":"wad","type":"uint256"}],"name":"approve","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"src","type":"address"},{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transferFrom","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"wad","type":"uint256"}],"name":"withdraw","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"}],"name":"balanceOf","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"name":"dst","type":"address"},{"name":"wad","type":"uint256"}],"name":"transfer","outputs":[{"name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"deposit","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":true,"inputs":[{"name":"","type":"address"},{"name":"","type":"address"}],"name":"allowance","outputs":[{"name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"guy","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Transfer","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"dst","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Deposit","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"name":"src","type":"address"},{"indexed":false,"name":"wad","type":"uint256"}],"name":"Withdrawal","type":"event"}]`

// WETH contract address
var wethAddress = "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"

// Register ABI for WETH contract
exchange.IO("abi", wethAddress, abiWETH)

// The wallet address of the currently configured exchange object
var walletAddress = exchange.IO("address")

// Coded WETH contract's deposit method call
var calldataForDeposit = exchange.IO("encode", wethAddress, "deposit")
Log("calldataForDeposit:", "0x" + calldataForDeposit)

// Get nonce
var nonce = exchange.IO("api", "eth", "eth_getTransactionCount", walletAddress, "pending")

// Get gasPrice
var gasPrice = exchange.IO("api", "eth", "eth_gasPrice")

// Call the deposit method to change ETH to WETH, you need to transfer ETH, here we convert 0.01ETH to a hexadecimal value in wei
var innerAmount = BigInt(Number(toInnerAmount(0.005, 18))).toString(16)

// The transaction call object:
var obj = {
    "from" : walletAddress,
    "to"  : wethAddress,
    "gasPrice" : gasPrice,
    "value" : "0x" + innerAmount,
    "data" : "0x" + calldataForDeposit,
}

// Calculate gasLimit
var gasLimit = exchange.IO("api", "eth", "eth_estimateGas", obj)

// Construct a transaction
var transaction = {
    "to": wethAddress,
    "value": toAmount("0x" + innerAmount, 0),   // Convert to decimal
    "data": "0x" + calldataForDeposit,
    "gasLimit": toAmount(gasLimit, 0),   // Convert to decimal
    "gasPrice": toAmount(gasPrice, 0),   // Convert to decimal
    "nonce": toAmount(nonce, 0),         // Convert to decimal
    "chainId": 1,                        // Ethereum mainnet Id
}
Log("transaction:", transaction)

// Signature, your key is replaced with your private key
var signedTx = Encode("signTx", "string", "hex", JSON.stringify(transaction), "hex", "0x" + "your key")
Log("signedTx:", "0x" + signedTx)

// Call eth_sendRawTransaction to send a transaction
var ret = exchange.IO("api", "eth", "eth_sendRawTransaction", "0x" + signedTx)
return ret
Enter fullscreen mode Exit fullscreen mode

}
`

Run in the debugging tool:

run
2023-06-15 09:58:50 Info signedTx: 0xf86f4f8504202067888...
2023-06-15 09:58:50 Info transaction: {"to":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2","value":5000000000000000,"data":"0xd0e30db0","gasLimit":27938,"gasPrice":17718863752,"nonce":79,"chainId":1}
2023-06-15 09:58:50 Info calldataForDeposit: 0xd0e30db0

Execute var ret = exchange.IO("api", "eth", "eth_sendRawTransaction", "0x" + signedTx) function and the returned Transaction Hash is: 0x2ff585504b0fe59b0122f696e8808abfe2f3ce263448066533f3bb8a4f55e8e6. The eth_sendRawTransaction call executes the calldata in it, calling the deposit method of the WETH contract to swap the 0.005 ETH sent for WETH.

Listening to mempool

Before a user's transaction is packaged into the Ethereum blockchain by miners, all transactions will be pooled in Mempool (transaction memory pool), where "miners" also look for transactions with high fees to be packaged first, in order to maximize mining benefits. Therefore, usually the higher the transaction's gasPrice setting, the more likely it is to be packaged.

Some transaction scripts will also sniff Mempool in the hope of finding some profitable transactions. For example, if a transaction is set with a high exchange slippage, the transaction could be subject to a "sandwich attack'' by these transactionscripts. So how do these scripts listen for pending (pending, to-be-packaged) transactions in Mempool?

Listening with the REST protocol

Use the RPC method we learned before: eth_getBlockByNumber, but we do not pass the specific blockNumber this time, we use the "pending" tag.

javascript
function main() {
var data = exchange.IO("api", "eth", "eth_getBlockByNumber", "pending", true)
if (Array.isArray(data.transactions)) {
for (var i = 0; i < data.transactions.length; i++) {
Log(data.transactions[i])
}
}
}

Run in the debugging tool:

run
2023-06-18 19:23:05 Info {"blockNumber":"0x10b2027","type":"0x2","accessList":[],"blockHash":"0xf833ed36435c53d63bd7109bb1e85383075534410c14573881bf26d912f46a89","from":"0xd50521974d62f1fa34b8e81cb742ccf6147d05ff","gasPrice":"0x32ea2db37","hash":"0xf8f10f8f473c340b021298feb48d0affe529e8737a309c4cc1902e8989ef0914","input":"0xa22cb4650000000000000000000000001e0049783f008a0085193e00003d00cd54003c710000000000000000000000000000000000000000000000000000000000000001","v":"0x0","value":"0x0","maxFeePerGas":"0x48a413364","maxPriorityFeePerGas":"0x5f5e100","nonce":"0x8","r":"0x8c1cc36f43b02c9e9e454153588cc9d38757f1da69ec49d3cfdda74ab69e06a8","s":"0x2f3dd3e5ddf9e5d42c128a8e900026aca7568fa83c68cf332e1328066ee8d03a","transactionIndex":"0x3a","chainId":"0x1","gas":"0x1142d","to":"0x8c3c0274c33f263f0a55d129cfc8eaa3667a9e8b"}
2023-06-18 19:23:05 Info {"input":"0x646174613a2c7b2270223a226572632d3230222c226f70223a226d696e74222c227469636b223a2265746873222c226964223a223139323732222c22616d74223a2231303030227d","nonce":"0x1d","blockHash":"0xf833ed36435c53d63bd7109bb1e85383075534410c14573881bf26d912f46a89","from":"0xe7fa86855af674837cea1b58f88b5352543ca27b","gas":"0x81cc","gasPrice":"0x32ea2db37","to":"0xe7fa86855af674837cea1b58f88b5352543ca27b","chainId":"0x1","transactionIndex":"0x39","type":"0x2","value":"0x0","accessList":[],"blockNumber":"0x10b2027","hash":"0x55702f5d14736fc9d0c58fdac2d2052a602db171c46b5e1fa9ff6af5c277f9a2","maxFeePerGas":"0x48a413364","maxPriorityFeePerGas":"0x5f5e100","r":"0x5a703d389d23b51adf8ef0f55db8876e7392636797b68a4be6afe73e76d7e1f2","s":"0x4b4bb11257c4434a0acc2672357f8793476e4bfdf98bc30d2389ce335e7de64e","v":"0x1"}
2023-06-18 19:23:05 Info {"gas":"0x186a0","nonce":"0x46533","r":"0xfeea052a4ac2283ca058a657a806ba0916d8e7d52d2a577f150c40eb1dfbec65","s":"0x5bf0089a3c060ba787b67a205b44e1065a0d11d132b41737ab9adf0f55066811","transactionIndex":"0x38","value":"0x78f0975742c400","blockHash":"0xf833ed36435c53d63bd7109bb1e85383075534410c14573881bf26d912f46a89","chainId":"0x1","hash":"0x56bdf1b38e23db66e8d1c4014d1e9f690a9217d8a0232489210325fc69e25cf9","v":"0x25","input":"0x","type":"0x0","blockNumber":"0x10b2027","gasPrice":"0x4a817c800","from":"0x97b9d2102a9a65a26e1ee82d59e42d1b73b68689","to":"0xcb513e99c020e9d15a6eafef873fef5d9f078221"}
...

Extract one piece of the data:

javascript
{
"blockNumber": "0x10b2027",
"type": "0x2",
"accessList": [],
"blockHash": "0xf833ed36435c53d63bd7109bb1e85383075534410c14573881bf26d912f46a89",
"from": "0xd50521974d62f1fa34b8e81cb742ccf6147d05ff",
"gasPrice": "0x32ea2db37",
"hash": "0xf8f10f8f473c340b021298feb48d0affe529e8737a309c4cc1902e8989ef0914",
"input": "0xa22cb4650000000000000000000000001e0049783f008a0085193e00003d00cd54003c710000000000000000000000000000000000000000000000000000000000000001",
"v": "0x0",
"value": "0x0",
"maxFeePerGas": "0x48a413364",
"maxPriorityFeePerGas": "0x5f5e100",
"nonce": "0x8",
"r": "0x8c1cc36f43b02c9e9e454153588cc9d38757f1da69ec49d3cfdda74ab69e06a8",
"s": "0x2f3dd3e5ddf9e5d42c128a8e900026aca7568fa83c68cf332e1328066ee8d03a",
"transactionIndex": "0x3a",
"chainId": "0x1",
"gas": "0x1142d",
"to": "0x8c3c0274c33f263f0a55d129cfc8eaa3667a9e8b"
}

Listening with the WebSocket protocol

In the FMZ Quant Trading Platform, we use the Dial function to create WebSocket connections, you can check the FMZ API documentation to learn the Dial function.

The test code in this section runs in the Ethereum mainnet environment, and it is easier to use the FMZ Quant to test in live trading due to the use of WebSocket protocol communication. The Websocket protocol subscription messages are:

javascript
{"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newPendingTransactions"]}

In addition to newPendingTransactions, you can also subscribe to newHeads, logs.

Receiving data pushed by WebSocket connections:

javascript
{
"jsonrpc": "2.0",
"method": "eth_subscription",
"params": {
"subscription": "0x2c5c087b4aa188e008f4747828ef4e61",
"result": "0x69c4251cecb814e17cfe7a5ee41742a616f9a4d1bbf245c49b186b1006fd14d3"
}
}

Then further query transaction according to which: "result": "0x69c4251cecb814e17cfe7a5ee41742a616f9a4d1bbf245c49b186b1006fd14d3". For a specific transaction, we use the Ethereum RPC method eth_getTransactionByHash to query.

`javascript
var ws = null

function main () {

// {"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["xxxxx"]} , "xxxxx" is the specific message to subscribe to
var payload = {"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newPendingTransactions"]}

// wss://mainnet.infura.io/ws/v3/xxxxx , "xxxxx" is your infura key
var infuraKey = "your key"

ws = Dial("wss://mainnet.infura.io/ws/v3/" + infuraKey + "|reconnect=true&payload=" + JSON.stringify(payload))
if (!ws) {
    throw "websocket link infura failed!"
}

// eth_getTransactionByHash call count
var getTransactionCounter = 0

var beginTS = new Date().getTime()

// Loop to get messages
while (true) {
    // Receive push messages
    var data = ws.read()
    if (data) {
        var ts = new Date().getTime()

        if (ts - beginTS >= 1000) {
            getTransactionCounter = 0
            beginTS = ts 
        }

        // Check transaction details based on txHash
        if (ts - beginTS < 1000 && getTransactionCounter >= 100) {
            Sleep(1000)
            getTransactionCounter = 0
            beginTS = ts 
        }

        var obj = JSON.parse(data)
        if (obj["params"] && obj["params"]["result"]) {
            var transcationInfo = exchange.IO("api", "eth", "eth_getTransactionByHash", obj["params"]["result"])
            Log(obj["params"]["result"], "transcationInfo:", transcationInfo)
        }

        getTransactionCounter++
    }

    LogStatus(_D())
}
Enter fullscreen mode Exit fullscreen mode

}

function onexit() {
Log("Disconnect WS connection")
ws.close()
}
`

Create a live trading to run the above code, you can receive the data pushed by the WebSocket connection, the data is pushed constantly, we extract one of them - transaction:

javascript
{
"maxPriorityFeePerGas": "0x5f5e100",
"nonce": "0x1a9",
"accessList": [],
"blockNumber": "0x10b1c9f",
"from": "0x5888700be02f52c8adf85890886ef84a6b8a7829",
"blockHash": "0x92c3d77ea218cdc0967ab74b6005bb393b92355047f206c7e2d59d41828e7fa9",
"chainId": "0x1",
"gasPrice": "0x34fdbf43d",
"s": "0x7d86ae29a786a61b9e74a7a9e2cc4b39b7913aa3d4c3816ccb07528fed82048a",
"to": "0xfc2068c3d47b575a60f6a4a7bf60dea0ac368e01",
"type": "0x2",
"v": "0x1",
"value": "0x0",
"gas": "0x1aad3",
"hash": "0x2c77c0704aefbb26db460cbb71efdb488df968ad53d2c2b3f1e1172056b40b22",
"input": "0x42842e0e0000000000000000000000005888700be02f52c8adf85890886ef84a6b8a7829000000000000000000000000d2d07e4d1bb0f40ac3e4aa7cc3ad05d348bfd2c3000000000000000000000000000000000000000000000000000000000000180b",
"maxFeePerGas": "0x4712d1273",
"r": "0x8ec58f95f6d9729a6eee075e6976658b6c5346cbc90eb68ac361a40af073b10e",
"transactionIndex": "0xc1"
}

Excerpted (partial omission) log data:

run
2023-06-18 16:20:07 Info Disconnect WS connection
2023-06-18 16:20:07 Info 0xba07ca903f9eafbfa7d494bb26197713034b9ca2dd3c19bc0898af3f35b59343 transcationInfo: {"accessList":[],"from":"0xe2977d60182da068dfd78693f96362ee7a2e9644","nonce":"0xf","value":"0x0","blockHash":"0x92c3d77ea218cdc0967ab74b6005bb393b92355047f206c7e2d59d41828e7fa9","blockNumber":"0x10b1c9f","chainId":"0x1","hash":"0xba07ca903f9eafbfa7d494bb26197713034b9ca2dd3c19bc0898af3f35b59343","maxFeePerGas":"0x530c30b70","r":"0xf28bfdf372a5401a2e00675c6ebe8d5e73f2c955db44b1aa56240b9197d6cbc7","type":"0x2","v":"0x0","gas":"0x21079","gasPrice":"0x367b3783d","input":"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","maxPriorityFeePerGas":"0x1dcd6500","s":"0x71d51246bb60e792f963a3c75c46fd8f557921ce6face7224c944e1768a76ca","to":"0x0b51eb9d0e54c562fedc07ceba453f05b70c4b79","transactionIndex":"0x40"}
2023-06-18 16:20:07 Info 0x2c77c0704aefbb26db460cbb71efdb488df968ad53d2c2b3f1e1172056b40b22 transcationInfo: {"maxPriorityFeePerGas":"0x5f5e100","nonce":"0x1a9","accessList":[],"blockNumber":"0x10b1c9f","from":"0x5888700be02f52c8adf85890886ef84a6b8a7829","blockHash":"0x92c3d77ea218cdc0967ab74b6005bb393b92355047f206c7e2d59d41828e7fa9","chainId":"0x1","gasPrice":"0x34fdbf43d","s":"0x7d86ae29a786a61b9e74a7a9e2cc4b39b7913aa3d4c3816ccb07528fed82048a","to":"0xfc2068c3d47b575a60f6a4a7bf60dea0ac368e01","type":"0x2","v":"0x1","value":"0x0","gas":"0x1aad3","hash":"0x2c77c0704aefbb26db460cbb71efdb488df968ad53d2c2b3f1e1172056b40b22","input":"0x42842e0e0000000000000000000000005888700be02f52c8adf85890886ef84a6b8a7829000000000000000000000000d2d07e4d1bb0f40ac3e4aa7cc3ad05d348bfd2c3000000000000000000000000000000000000000000000000000000000000180b","maxFeePerGas":"0x4712d1273","r":"0x8ec58f95f6d9729a6eee075e6976658b6c5346cbc90eb68ac361a40af073b10e","transactionIndex":"0xc1"}
2023-06-18 16:20:07 Info 0xbc42d5db10e5cb2e888c76005c522cb2474a0c0a7325feb867b618f69ff26f2a transcationInfo: {"accessList":[],"blockNumber":"0x10b1c9f","gas":"0x1cc12b","hash":"0xbc42d5db10e5cb2e888c76005c522cb2474a0c0a7325feb867b618f69ff26f2a","maxFeePerGas":"0x6ab262e5c","value":"0x0","v":"0x1","chainId":"0x1","from":"0xc1b634853cb333d3ad8663715b08f41a3aec47cc","input":"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
2023-06-18 16:20:06 Info 0xff0945c3d682a37e18ee433d56c8bedbb93d9ac368af968ed8d53b655575e8e5 transcationInfo: {"gas":"0x5208","s":"0x63572e1fa060841b939cea0849154e55781fe0efcbdfe5ce6979b44ce0980e4a","transactionIndex":"0xa7","value":"0x113e9d515e400","blockHash":"0x92c3d77ea218cdc0967ab74b6005bb393b92355047f206c7e2d59d41828e7fa9","hash":"0xff0945c3d682a37e18ee433d56c8bedbb93d9ac368af968ed8d53b655575e8e5","nonce":"0x2","r":"0x698fe26331ad39ba89c4d30985b707792ea4ab09b25205727f8fac2a6120b54a","gasPrice":"0x35458af00","from":"0x228d93af92d03184c07aa9e39b3d2d61b666686d","input":"0x","to":"0x0246177b98a5e42835cdcfaac1c274d3e6c39486","v":"0x26","blockNumber":"0x10b1c9f","type":"0x0","chainId":"0x1"}
...

Decoding Transaction Details

In the previous course, we wrote a monitoring program to monitor pending transactions on Ethereum, get the pushed transaction hash via WebSocket protocol, and then query the specific transaction details based on the transaction hash.

Next we want to do further parsing of the input field data in the transaction details data. The input field data looks like a jumble of hexadecimal data, but it actually encodes the content of the transaction: including the functions called, and the parameters entered, etc.

After repeated and extensive testing, we found that the timeliness and quantity of data pushed over by the WebSocket connection has a lot to do with the RPC node currently in use, and the pushed data received by two different RPC node services (e.g., infura, ALCHEMY) when creating a WebSocket connection at the same time is not exactly the same, and since the current scenario generates a large number of requests, we still need to use a more stable and faster RPC service. The WebSocket connection also pushes a lot of transaction hashes that have been Pending for a long time, and when using eth_getTransactionByHash to query, you often get a null value (tested on FMZ, node.js).

We use the alchemy RPC node this time: wss://eth-mainnet.g.alchemy.com/v2/oKmOQKbneVkxgHZfibs-iFhIlIAl6HDN. The node supports both WebSocket and REST protocols.

We monitor the multicall(uint256,bytes[]) method of the router smart contract of the Uniswap decentralized exchange, so we need to calculate the function signature hash of the method first.


// Take the first 8 characters of the complete hash
// multicall: 0x5ae401dc
var sigHash = "0x" + Encode("keccak256", "string", "hex", "multicall(uint256,bytes[])").slice(0, 8)

Based on the example in the previous lesson, we have made some modifications. When receiving messages pushed by the WebSocket connection, the latest data is received using var data = ws.read(-2) method, and the read() function parameter is set to -2 to indicate that the latest data is returned immediately. We only care about the Transaction that contains the multicall call, using if (tx && tx.input.indexOf(sigHash) ! == -1) to determine the filter.

2 custom functions need to be designed:

  • calcAllFuncSigHash(): Calculate signature hash for all methods based on ABI.
  • decodeCall(): Decoding function.

Next, when the multicall call is detected, the decoding operation can start, and the parameters of the multicall method are decoded for the first time: deadline and data. deadline is a timestamp that is better understood, and data is another encoded calldata, so you still need to continue to use the decodeCall() function to decode it.

Example of a complete implementation:

`javascript
var ws = null
var arrLog = []

const ABI_Route = '[{"inputs":[{"internalType":"address","name":"_factoryV2","type":"address"},{"internalType":"address","name":"factoryV3","type":"address"},{"internalType":"address","name":"_positionManager","type":"address"},{"internalType":"address","name":"_WETH9","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH9","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes","name":"data","type":"bytes"}],"name":"callPositionManager","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"paths","type":"bytes[]"},{"internalType":"uint128[]","name":"amounts","type":"uint128[]"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactInputParams","name":"params","type":"tuple"}],"name":"exactInput","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactInputSingleParams","name":"params","type":"tuple"}],"name":"exactInputSingle","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactOutputParams","name":"params","type":"tuple"}],"name":"exactOutput","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactOutputSingleParams","name":"params","type":"tuple"}],"name":"exactOutputSingle","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"factory","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"factoryV2","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"getApprovalType","outputs":[{"internalType":"enum IApproveAndCall.ApprovalType","name":"","type":"uint8"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint256","name":"tokenId","type":"uint256"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"}],"internalType":"struct IApproveAndCall.IncreaseLiquidityParams","name":"params","type":"tuple"}],"name":"increaseLiquidity","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"int24","name":"tickLower","type":"int24"},{"internalType":"int24","name":"tickUpper","type":"int24"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"internalType":"struct IApproveAndCall.MintParams","name":"params","type":"tuple"}],"name":"mint","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes32","name":"previousBlockhash","type":"bytes32"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"results","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"positionManager","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"pull","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"refundETH","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermit","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowed","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowedIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapExactTokensForTokens","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMax","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapTokensForExactTokens","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"int256","name":"amount0Delta","type":"int256"},{"internalType":"int256","name":"amount1Delta","type":"int256"},{"internalType":"bytes","name":"_data","type":"bytes"}],"name":"uniswapV3SwapCallback","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"value","type":"uint256"}],"name":"wrapETH","outputs":[],"stateMutability":"payable","type":"function"},{"stateMutability":"payable","type":"receive"}]'

function calcAllFuncSigHash(jsonABI) {
var mapSigHash = {}
for (var i in jsonABI) {
var ele = jsonABI[i]
if (typeof(ele["name"]) != "undefined") {
if (ele["inputs"]) {
var funcName = ele["name"]
if (ele["inputs"].length == 0) {
var methodId = "0x" + Encode("keccak256", "string", "hex", funcName + "()").slice(0, 8)
mapSigHash[methodId] = {"argsTypeList": [], "argsNameList": [], "funcName": funcName}
} else {
var arr = []
var arrName = []
var argPrototype = []
for (var j in ele["inputs"]) {
var inputType = ele["inputs"][j]["type"]
if (inputType == "tuple") {

var components = ele["inputs"][j]["components"]
var tupleType = []
var protoType = []
for (var componentsIdx = 0; componentsIdx < components.length; componentsIdx++) {
tupleType.push(components[componentsIdx]["type"])
protoType.push(components[componentsIdx]["name"] + " " + components[componentsIdx]["type"])
}
arr.push("(" + tupleType.join() + ")")
arrName.push(ele["inputs"][j]["name"])
// Prototype
argPrototype.push("tuple" + "(" + protoType.join() + ")")
} else {
arr.push(inputType)
arrName.push(ele["inputs"][j]["name"])
// Prototype
argPrototype.push(inputType)
}

}
var functionSignature = funcName + "(" + arr.join() + ")"
var methodId = "0x" + Encode("keccak256", "string", "hex", functionSignature).slice(0, 8)
mapSigHash[methodId] = {"argsTypeList": arr, "argsNameList": arrName, "funcName": funcName, "argPrototype": argPrototype}
}
}
}
}
return mapSigHash
}

function decodeCall(input, abi) {
var mapSigHash = calcAllFuncSigHash(JSON.parse(abi))
var methodId = input.slice(0, 10)
var data = input.slice(10)

var decodedArgs = {}
var infoMethod = mapSigHash[methodId]
if (typeof(infoMethod) == "undefined") {
    return [methodId, mapSigHash]
}

var arr = []
for (var i = 0; i < infoMethod["argsTypeList"].length; i++) {
    if (infoMethod["argsTypeList"][i].startsWith("(")) {
        arr.push(infoMethod["argPrototype"][i])
    } else {
        arr.push(infoMethod["argsTypeList"][i])
    }
}

if (arr.length == 0) {
    return {"funcName": infoMethod["funcName"], "args": decodedArgs}
}

var args = exchange.IO("decode", arr.join(), data)

if (!Array.isArray(args)) {
    args = [args]
}

if (args.length != infoMethod["argsNameList"].length) {
    Log("args:", args)
    Log("infoMethod:", infoMethod)
    throw "The decoded args are not equal to the argsNameList"
}

for (var i = 0; i < infoMethod["argsNameList"].length; i++) {
    var key = infoMethod["argsNameList"][i]
    var value = args[i]
    decodedArgs[key] = value
}

return {"funcName": infoMethod["funcName"], "args": decodedArgs}
Enter fullscreen mode Exit fullscreen mode

}

function main () {
// {"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["xxxxx"]} , "xxxxx" is the specific message of the subscription
var payload = {"jsonrpc": "2.0", "id": 1, "method": "eth_subscribe", "params": ["newPendingTransactions"]}

// Use the alchemy service
ws = Dial("wss://eth-mainnet.g.alchemy.com/v2/oKmOQKbneVkxgHZfibs-iFhIlIAl6HDN" + "|reconnect=true&payload=" + JSON.stringify(payload))
if (!ws) {
    throw "websocket link to alchemy failed!"
}

// eth_getTransactionByHash call count
var getTransactionCounter = 0

// Start Timestamp
var beginTS = new Date().getTime()

// Calculate function signature hash
var sigHash = "0x" + Encode("keccak256", "string", "hex", "multicall(uint256,bytes[])").slice(0, 8)
Log("sigHash:", sigHash)

// Loop for messages
while (true) {
    var msg = ""
    var recv = null
    // Receive pushed messages, use the read parameter -2, and return the latest data immediately
    var data = ws.read(-2)
    if (data && data != "") {
        var ts = new Date().getTime()

        if (ts - beginTS >= 1000) {
            getTransactionCounter = 0
            beginTS = ts 
        }

        // Check transaction details based on txHash
        if (ts - beginTS < 1000 && getTransactionCounter >= 100) {
            Sleep(1000)
            getTransactionCounter = 0
            beginTS = ts 
        }

        var obj = JSON.parse(data)
        if (obj["params"] && obj["params"]["result"]) {
            var txHash = obj["params"]["result"]
            var tx = exchange.IO("api", "eth", "eth_getTransactionByHash", txHash)

            if (tx && tx.input.indexOf(sigHash) !== -1) {
                // Decode transaction details
                arrLog = []
                var decodedInput = decodeCall(tx.input, ABI_Route)

                // Log("----------------", txHash, "/", decodedInput["funcName"], "----------------", "#FF0000")
                arrLog.push("----------------" + txHash + "/" + decodedInput["funcName"] + "----------------" + "#FF0000")
                arrLog.push(tx.from + " -> " + tx.to)

                for (var i = 0; i < decodedInput["args"]["data"].length; i++) {
                    var calldata = "0x" + decodedInput["args"]["data"][i]
                    var decodedCalldata = decodeCall(calldata, ABI_Route)

                    // Log("----------------", decodedCalldata["funcName"], "----------------", "#FF0000")
                    arrLog.push("----------------" + decodedCalldata["funcName"] + "----------------" + "#FF0000")

                    for (var key in decodedCalldata["args"]) {
                        // Log(key, decodedCalldata["args"][key])
                        arrLog.push(key + ": " + JSON.stringify(decodedCalldata["args"][key]))
                    }
                }

                // Output logs
                for (var logIdx = arrLog.length - 1; logIdx >= 0; logIdx--) {
                    Log(arrLog[logIdx])
                }
            }

            getTransactionCounter++
        }
        recv = obj
    } else if (data == null) {
        msg = "The buffer queue is empty, time:" + _D()
    }

    LogStatus(_D(), ", msg:", msg, ", recv:", recv)
}
Enter fullscreen mode Exit fullscreen mode

}

function onexit() {
Log("Disconnect WS connection")
ws.close()
}

function onerror() {
Log("Disconnect WS connection")
ws.close()

for (var logIdx = arrLog.length - 1; logIdx >= 0; logIdx--) {        
    Log(arrLog[logIdx])
}
Enter fullscreen mode Exit fullscreen mode

}
`

Create a live trading to test:

run
2023-06-20 17:01:00 Info ----------------0x5288a7bd6e0f57162ca763df722de73793e542734d7d2b7af5755664e2e67910/multicall----------------
2023-06-20 17:01:00 Info 0x851b594033d57c98af753bcb3a7d0237a615de32 -> 0x68b3465833fb72a70ecdf485e0e4c7bd8665fc45
2023-06-20 17:01:00 Info ----------------exactInputSingle----------------
2023-06-20 17:01:00 Info params: {"tokenOut":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2","fee":"10000","recipient":"0x0000000000000000000000000000000000000002","amountIn":"8952087000296027130940868","amountOutMinimum":"41638694112306829","sqrtPriceLimitX96":"0","tokenIn":"0xe1283567345349942acdfad3692924a1b16cf3cc"}
2023-06-20 17:01:00 Info ----------------unwrapWETH9----------------
2023-06-20 17:01:00 Info amountMinimum: "41638694112306829"
2023-06-20 17:01:00 Info recipient: "0x851b594033d57c98af753bcb3a7d0237a615de32"
2023-06-20 16:59:03 Info ----------------0x55e0c4a38a17d3aa6e8f558a66c77e9defa9f8f6e347536363ac1b921de9aaf3/multicall----------------
2023-06-20 16:59:03 Info 0x27457ada2dd725c7d0f28e1737bdd0bf583c0f0b -> 0x68b3465833fb72a70ecdf485e0e4c7bd8665fc45
2023-06-20 16:59:03 Info ----------------swapExactTokensForTokens----------------
2023-06-20 16:59:03 Info amountIn: "816769666850161"
2023-06-20 16:59:03 Info amountOutMin: "40404501509302321"
2023-06-20 16:59:03 Info path: ["0x7863e06bca47ded821fcb53ab788eeb371243eda","0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2"]
2023-06-20 16:59:03 Info to: "0x27457ada2dd725c7d0f28e1737bdd0bf583c0f0b"
2023-06-20 16:58:25 Info sigHash: 0x5ae401dc

Screenshot:

Image description

You can see that the Transaction Hash is 0x5288a7bd6e0f57162ca763df722de73793e542734d7d2b7af5755664e2e67910 for this transaction, and the input data data contains the call to a multicall method call. This transaction is sent in the direction: 0x851b594033d57c98af753bcb3a7d0237a615de32 -> 0x68b3465833fb72a70ecdf485e0e4c7bd8665fc45. 0x68b3465833fb72a70ecdf485e0e4c7bd8665fc45 is Uniswap's router contract address.

Image description

The multicall package is parsed to call the contract's exactInputSingle and unwrapWETH9 methods and the specific parameters of these methods.

`
----------------exactInputSingle----------------
params: {
"tokenOut":"0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2",
"fee":"10000",
"recipient":"0x0000000000000000000000000000000000000002",
"amountIn":"8952087000296027130940868",
"amountOutMinimum":"41638694112306829",
"sqrtPriceLimitX96":"0",
"tokenIn":"0xe1283567345349942acdfad3692924a1b16cf3cc"
}

----------------unwrapWETH9----------------
amountMinimum: "41638694112306829"
recipient: "0x851b594033d57c98af753bcb3a7d0237a615de32"
`

If you are interested, you can modify and extend the example based on it to monitor more transactions and parse these on-chain operations.

From: https://blog.mathquant.com/2023/06/30/get-started-with-web3-development-easily-based-on-ethereum-using-fmz.html

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