web3调用智能合约取事件

合约地址示例

https://hecoinfo.com/address/0x910651F81a605a6Ef35d05527d24A72fecef8bF0#code

在取abi的时候，要先看当前合约是否为代理合约，如果是代理合约的话需要去取源合约的api，因为我们是调用源合约的方法，不能直接通过代理合约去调用源合约的方法(个人理解，有误指正)

以下是代理合约

点击跳转到源合约：https://hecoinfo.com/address/0x543a2ae552d993342a92e87aefc966b69534a798#code

拿到他的abi

getPastEvents调用合约

web3文档 https://web3js.readthedocs.io/en/v1.3.4/web3-eth-contract.html#getpastevents

初始化Contract

import Web3 from 'web3'
import contractABI from '../ABI/contractABI.json'//contractABI为上面源合约地址的abi

const web3 = new Web3(window.ethereum)
var myContractInstance = new web3.eth.Contract(contractABI, adderss, {
    from: '0x23FCB0E1DDbC821Bd26D5429BA13B7D5c96C0DE0',
    gasPrice: '100',
	...
});

adderss取值为代理合约，也就是我们自己合约地址的address，并非源合约地址的address

调用合约

获取所有合约事件

myContractInstance.getPastEvents('allEvents', {filter: {}, fromBlock: 0, toBlock: 'latest'}).then((res) => {
            console.log(res)
        })

获取指定合约事件

myContractInstance.getPastEvents('ChargeFee', {filter: {}, fromBlock: 0, toBlock: 'latest'}).then((res) => {
            console.log(res)
        })

哪些是事件?

demo

import React from 'react'
import Web3 from 'web3'
import contractABI from '../ABI/contractABI.json'

const web3 = new Web3(window.ethereum)
var myContractInstance = new web3.eth.Contract(contractABI, '0x910651F81a605a6Ef35d05527d24A72fecef8bF0', {
    from: '0x23FCB0E1DDbC821Bd26D5429BA13B7D5c96C0DE0',
    gasPrice: '100'
});

export default function Demo() {
    const getAllEvens = () => {
        myContractInstance.getPastEvents('allEvents', {filter: {}, fromBlock: 0, toBlock: 'latest'}).then((res) => {
            console.log(res)
        })
    }
    const getEven = (event) => {
        myContractInstance.getPastEvents(event, {filter: {}, fromBlock: 0, toBlock: 'latest'}).then((res) => {
            console.log(res)
        })
    }
    return (
        
            获取所有事件allEvents
             getEven('Transfer')}>获取单个事件Transfer
             getEven('ChargeFee')}>获取单个事件ChargeFee
        
    )
}

结果

合约是在以太坊主链上的，需要连接以太坊主链才能获取到数据，否则为空数组

获取全部和获取某一个事件的区别貌似就是，获取单个事件是从全部事件里面筛选出来的，相当于一个query参数(个人理解)，不过这样请求速度肯定会更快