How do I get the correct 4bytes?

Question

I'm using this tool to get the keccak 256 hash: https://emn178.github.io/online-tools/keccak_256.html

However I'm trying to the 4bytes for executeOrder.

The executeOrder function signature is this:

function executeOrder(BaseOrderUtils.ExecuteOrderParams memory params) external

The ExecuteOrderParams struct looks like the following:

    struct ExecuteOrderParams {
        ExecuteOrderParamsContracts contracts;
        bytes32 key;
        Order.Props order;
        Market.Props[] swapPathMarkets;
        uint256[] minOracleBlockNumbers;
        uint256[] maxOracleBlockNumbers;
        Market.Props market;
        address keeper;
        uint256 startingGas;
        Order.SecondaryOrderType secondaryOrderType;
    }

How do I get the right 4bytes from keccak_256? What do I pass in?

Answer 1

By 4bytes for executeOrder, you might be referring to the bytes corresponding to its function selector.

You can get the same, by using solidity (i.e., by adding a function within the same contract) as well as by using library like ethers.js in javascript.

Using Solidity:

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.24;

contract Market {
    struct Props { 
        address marketToken; 
        address indexToken; 
        address longToken; 
        address shortToken; 
    }
}

contract YourContract {

    // Define the ExecuteOrderParams struct
    struct ExecuteOrderParams {
        // Define struct properties here
        string stringParam;
        uint256 uintParam;
        Market.Props market;
        Market.Props[] swapPathMarkets;
    }
    
    // Function to execute order
    function executeOrder(ExecuteOrderParams memory params) external {
        // Implementation of the executeOrder function
    }
    
    // Function to get function signature bytes for executeOrder
    function getExecuteOrderSignature() external pure returns (bytes4) {
        return this.executeOrder.selector;
    }
}

Using Javascript:

const { ethers } = require("ethers");

// ABI of the contract containing the executeOrder() function
const abi = [ { "inputs": [ { "components": [ { "internalType": "string", "name": "stringParam", "type": "string" }, { "internalType": "uint256", "name": "uintParam", "type": "uint256" }, { "components": [ { "internalType": "address", "name": "marketToken", "type": "address" }, { "internalType": "address", "name": "indexToken", "type": "address" }, { "internalType": "address", "name": "longToken", "type": "address" }, { "internalType": "address", "name": "shortToken", "type": "address" } ], "internalType": "struct Market.Props", "name": "market", "type": "tuple" }, { "components": [ { "internalType": "address", "name": "marketToken", "type": "address" }, { "internalType": "address", "name": "indexToken", "type": "address" }, { "internalType": "address", "name": "longToken", "type": "address" }, { "internalType": "address", "name": "shortToken", "type": "address" } ], "internalType": "struct Market.Props[]", "name": "swapPathMarkets", "type": "tuple[]" } ], "internalType": "struct YourContract.ExecuteOrderParams", "name": "params", "type": "tuple" } ], "name": "executeOrder", "outputs": [], "stateMutability": "nonpayable", "type": "function" }, { "inputs": [], "name": "getExecuteOrderSignature", "outputs": [ { "internalType": "bytes4", "name": "", "type": "bytes4" } ], "stateMutability": "pure", "type": "function" } ]

// Create an instance of the Contract interface
const iface = new ethers.utils.Interface(abi);

// Get the function selector for the executeOrder function
const executeOrderSelector = iface.getSighash("executeOrder");

console.log(executeOrderSelector);

P.S., You can modify the properties of the struct ExecuteOrderParams as per your use-case. Also, use the contract's ABI accordingly.

Answer 2

In Solidity you can do:

import "contract.sol";

function getSelector() public view returns (bytes4) {
    return contract.executeOrder.selector;
}