获取所有事件&解析参数

封装获取所有事件的方法

const getEvents = (address, topic0, fromBlock = 1) => {return new Promise((resolve, reject) => {axios({method: 'get',url: `https://api.hecoinfo.com/api?module=logs&action=getLogs&fromBlock=${fromBlock}&toBlock=latest&address=${address}&topic0=${topic0}&apikey=982S8JF95E4K4J46SMA2Y4I93UZH5WRMIC`}).then(async res => {let result = res.data.resultif (result.length >= 1000) {result = result.concat(await getEvents(address, topic0, Number(result[result.length - 1].blockNumber+1)))} else {resolve(result)}}).catch((e) => {reject()})})}

使用

import {getWeb3 as getClientWeb3, Contract as ClientContract} from '@chainstarter/multicall-client.js'//事件名称const eventName = 'CreatePropose'const web3 = getClientWeb3(ChainId.HECO)// 事件abiconst eventAbi = abis.find(item => item.name === eventName && item.type === 'event')// 获取事件topic0const topic0 = web3.eth.abi.encodeEventSignature(eventAbi)// 获取eventName所有事件const datas = await getEvents(voteMain.address, topic0, 1)const eventsData= []// 解析参数for (let i = 0; i < datas.length; i++) {const eventItem = web3.eth.abi.decodeLog(eventAbi.inputs, datas[i].data,datas[i].topics.slice(1))eventsData.push(eventItem)calls.push(voteNFTContract.tokenURI(eventItem.NFTtokenId))}

获取所有事件,用的是浏览器api

文档地址:https://hecoinfo.com/apis#logs

虽然不限制块高度,但是api数据返回最高1000条,值得注意的是,一个块中可能存在多个事件,如果要严谨一点,将 Number(result[result.length - 1].blockNumber+1) 的+1去掉,然后将结果进行去重即可


获取topic0,encodeEventSignature

通过web3.eth.abi.encodeEventSignature(eventName);


解析log data 使用 decodeLog

通过web3.eth.abi.decodeLog(inputs, hexString, topics);

注意,参数 3 topics,带有日志索引参数的topic的数组,如果是非匿名事件则不带topics[0],否则带topics[0]

像以下这种,是带有日志索引参数的 indexed

event CreatePropose(uint indexed propID, stringsubject,stringcontent,uint NFTtokenId,uint iwoAmountUSDT,uint warPrice,uint stakeAmount,uint begin);

通过getPastEvents获取事件

import {getWeb3} from "@chainstarter/multicall-client.js";const web3 = getWeb3(ChainId.BSC)var contract = new web3.eth.Contract(contractABI, adderss);//get eventcontract.getPastEvents('EventA', {filter: {}, fromBlock: 10000, toBlock: 'latest'}).then((res) => {console.log(res)})

获取所有事件同理,先获取最新的块高度,因为每次最多只能查5000个块,所以每次fromBlock与toBlock递增查询,当需要查询很多块的时候,这将不适用,不建议使用,但是用来监听最新块,用这个方法还是挺好的

方法参数解码

const funcName = 'claim'const funcAbi = abis.find(item => item.name === funcName && item.type === 'function')const encodeFunS = web3.eth.abi.encodeFunctionSignature(funcAbi)const paramsData = '0x' + decodeParams.replace(encodeFunS, '')const data = web3.eth.abi.decodeParameters(funcAbi.inputs, '0x0.........')