# 使用truffle部署合约练习ethers库，对比web3js与ethers的使用

**Published by:** [Easyplux](https://paragraph.com/@easyplux/)
**Published on:** 2022-06-18
**URL:** https://paragraph.com/@easyplux/truffle-ethers-web3js-ethers

## Content

前言使用 truffle部署合约，并练习ethers库。 之前一直是使用web3js，今天看到一个源码使用了ethers，看了之后感觉比web3js方便很多。web3js 与 ethers对比连接到以太坊// web3 var Web3 = require('web3'); var web3 = new Web3('http://localhost:8545'); // ethers var ethers = require('ethers'); const url = "http://127.0.0.1:8545"; const provider = new ethers.providers.JsonRpcProvider(url); 签名对象在ethers中，签名者是以太坊账户的抽象。它可用于对消息和交易进行签名，并将签名的交易发送到以太坊网络。 在 web3 中，可以使用一个帐户来签署消息和交易。// web3 const account = web3.eth.accounts.create(); // ethers (create random new account) const signer = ethers.Wallet.createRandom(); // ethers (connect to JSON-RPC accounts) const signer = provider.getSigner(); 使用私钥生成账号对象生成调用的方法不同，不过使用上大同小异。// web3 const signer = web3.eth.accounts.privateKeyToAccount(private_key) //ethers const signer = new ethers.Wallet(private_key); 账号签名// web3 (using a private key) signature = web3.eth.accounts.sign('Some data', privateKey) // ethers signature = await signer.signMessage('Some data') 合约调用只读方法// web3js const contract = new this.web3.eth.Contract(abi, contract_address) const token_blance = await contract.methods.balanceOf(wallet_address).call() const blance = this.web3.utils.fromWei(token_blance, 'ether') // ethers const daiContract = new ethers.Contract(daiAddress, daiAbi, provider); const res = await daiContract.balanceOf(myaddress).toString() 上述方法中使用web3js需要去下载相应的ABI，比如你可以去etherscan下载，而在ethers中，你可以直接传入方法生成daiAbiconst daiAbi = [ // Some details about the token "function name() view returns (string)", "function symbol() view returns (string)", // Get the account balance "function balanceOf(address) view returns (uint)", // Send some of your tokens to someone else "function transfer(address to, uint amount)", // An event triggered whenever anyone transfers to someone else "event Transfer(address indexed from, address indexed to, uint amount)" ]; const daiContract = new ethers.Contract(daiAddress, daiAbi, provider); 实践目标1.使用truffle部署一个合约 2.使用truffle console 进行交互 3.使用ethers进行合约交互练习安装环境yarn global add truffle yarn install ethers # 或者 npm install -g truffle npm install ethers 编写合约实现一个最简单的合约// SPDX-License-Identifier: GPL-3.0 pragma solidity 0.8.0; /** * @title Storage * @dev Store & retrieve value in a variable */ contract Storage { uint256 number; /** * @dev Store value in variable * @param num value to store */ function store(uint256 num) public { number = num; } /** * @dev Return value * @return value of 'number' */ function retrieve() public view returns (uint256){ return number; } } # 编译 truffle compile # 部署 truffle migrate Starting migrations... ====================== > Network name: 'development' > Network id: 1 > Block gas limit: 6721975 (0x6691b7) 1_initial_migration.js ====================== Replacing 'Migrations' ---------------------- > transaction hash: 0x67c58fd2401c5bc506591f30b9566be6e8226c8b09a8125a511224cfa5029f7f > Blocks: 0 Seconds: 0 > contract address: 0x25A6E016CB92D46fe8cE3f74D4F93b6439F6Cc89 > block number: 14820726 > block timestamp: 1653184639 > account: 0x4BC9E31c338C402Aa2590E7008a879B5a66A8568 > balance: 99.995114 > gas used: 244300 (0x3ba4c) > gas price: 20 gwei > value sent: 0 ETH > total cost: 0.004886 ETH > Saving migration to chain. > Saving artifacts ------------------------------------- > Total cost: 0.004886 ETH 2_deploy_contracts.js ===================== Replacing 'Storage' ------------------- > transaction hash: 0x45ae44d9c9730485b0208dbbb0d1116398f9d562931024fc9757e5b603160cc1 > Blocks: 0 Seconds: 0 > contract address: 0xFe87778700B9dda2B5FD5fb7895120C33a331E69 > block number: 14820728 > block timestamp: 1653184640 > account: 0x4BC9E31c338C402Aa2590E7008a879B5a66A8568 > balance: 99.9918876 > gas used: 118807 (0x1d017) > gas price: 20 gwei > value sent: 0 ETH > total cost: 0.00237614 ETH > Saving migration to chain. > Saving artifacts ------------------------------------- > Total cost: 0.00237614 ETH Summary ======= > Total deployments: 2 > Final cost: 0.00726214 ETH 部署完成之后，我们可以使用 truffle console 进行交互let ins = await Storage.deployed() await ins.store(7) let n2 = await ins.retrieve() n2 # BN { negative: 0, words: [ 7, <1 empty item> ], length: 1, red: null } 所以上述合约就只有2个方法 一个read方法：retrieve 一个write方法：store 所以通过 truffle 可以直接跟他进行交互 代码实现的功能：调用storage合约，将number修改为10，并且读取一次number的值。 ethers可以直接根据方法名生成abi，比web3js方便很多。const { ethers } = require("ethers"); const provider = new ethers.providers.JsonRpcProvider("http://127.0.0.1:8545"); (async () => { const num = await provider.getBlockNumber(); console.log(num); const singer = new ethers.Wallet( "private_key" ); const myaddress = singer.address; console.log(myaddress); const signature = await singer.signMessage("some data"); console.log(signature); const contractAddress = "0xFe87778700B9dda2B5FD5fb7895120C33a331E69"; const storageAbi = [ "function retrieve() view returns (uint256)", "function store(uint256 num)", ]; // The Contract object const storageContract = new ethers.Contract( contractAddress, storageAbi, provider.getSigner() ); const res = await storageContract.store(10); console.log(res); const res2 = await storageContract.retrieve(); console.log(res2.toString()); })(); 综上所述，对比web3js，ethers封装了更方便的api接口，能简化一些调用流程。参考Ethers Getting Started

## Publication Information

- [Easyplux](https://paragraph.com/@easyplux/): Publication homepage
- [All Posts](https://paragraph.com/@easyplux/): More posts from this publication
- [RSS Feed](https://api.paragraph.com/blogs/rss/@easyplux): Subscribe to updates