Hardhat以太坊智能合约开发框架基础教程

一、Hardhat框架介绍

Hardhat是一个基于javascript和solidity的开发框架。可实现编译、部署、测试、开源和调试以太坊应用的开发环境。Hardhat是一个围绕任务和插件的概念设计的;Hardhat 的大部分功能来自插件。Chain区块链开发群593674370

二、Hardhat框架优点

1、Hardhat 拥有大量插件，并允许自定义、灵活性和可扩展性。

2、Hardhat运行同时使用ether.js和web3.js。

3、Hardhat有良好的 console.log() 调试能力；会在调试时提供代码中发生的堆栈跟踪。

4、Hardhat 提供原生Typescript支持，并且还有一个Vscode扩展，为 Vscode 编辑器添加了可靠的支持。

5、Hardhat 带有一个内置的本地以太坊网络，称为Hardhat Network，用于在本地机器上运行和部署智能合约，是一个专为开发而设计的本地以太坊网络节点。

三、哪些项目在使用Hardhat

Chainlink ；Uniswap；Aave ；SushiSwap ； ENS 等主流项目。

四、Hardhat环境搭建

1、请安装node.js 12.x及以上的版本

2、Hardhat先安装到本地。

npm install --save-dev hardhat

3、先创建一个空文件夹执行安装命令;通过执行 npx hardhat 创建项目。

npx hardhat

初始化后项目结构。

五、创建编译合约

1、在contracts目录下编写一个合约文件 Token.js

// SPDX-License-Identifier: MITpragma solidity ^0.8.8;library SafeMath {function add(uint256 a, uint256 b) internal pure returns (uint256) {uint256 c = a + b;require(c >= a, "SafeMath: addition overflow");return c;}function sub(uint256 a, uint256 b) internal pure returns (uint256) {require(b <= a, "SafeMath: subtraction overflow");uint256 c = a - b;return c;}function mul(uint256 a, uint256 b) internal pure returns (uint256) {if (a == 0) {return 0;}uint256 c = a * b;require(c / a == b, "SafeMath: multiplication overflow");return c;}function div(uint256 a, uint256 b) internal pure returns (uint256) {// Solidity only automatically asserts when dividing by 0require(b > 0, "SafeMath: division by zero");uint256 c = a / b;// assert(a == b * c + a % b); // There is no case in which this doesn't holdreturn c;}function mod(uint256 a, uint256 b) internal pure returns (uint256) {require(b != 0, "SafeMath: modulo by zero");return a % b;}
}
interface IERC20 {function totalSupply() external view returns (uint256);function balanceOf(address account) external view returns (uint256);function transfer(address recipient, uint256 amount) external returns (bool);function allowance(address owner, address spender) external view returns (uint256);function approve(address spender, uint256 amount) external returns (bool);function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);event Transfer(address indexed from, address indexed to, uint256 value);event Approval(address indexed owner, address indexed spender, uint256 value);
}abstract contract ERC20Detailed is IERC20 {string private _name;string private _symbol;uint8 private _decimals;constructor (string memory tokenName, string memory tokenSymbol, uint8 tokenDecimals)  {_name = tokenName;_symbol = tokenSymbol;_decimals = tokenDecimals;}function name() public view returns (string memory) {return _name;}function symbol() public view returns (string memory) {return _symbol;}function decimals() public view returns (uint8) {return _decimals;}
}contract ERC20 is IERC20 {using SafeMath for uint256;mapping (address => uint256) private _balances;mapping (address => mapping (address => uint256)) private _allowances;uint256 private _totalSupply;function totalSupply() public view returns (uint256) {return _totalSupply;}function balanceOf(address account) public view returns (uint256) {return _balances[account];}function transfer(address recipient, uint256 amount) public returns (bool) {_transfer(msg.sender, recipient, amount);return true;}function allowance(address owner, address spender) public view returns (uint256) {return _allowances[owner][spender];}function approve(address spender, uint256 value) public returns (bool) {_approve(msg.sender, spender, value);return true;}function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {_transfer(sender, recipient, amount);_approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount));return true;}function _transfer(address sender, address recipient, uint256 amount) internal {require(sender != address(0), "ERC20: transfer from the zero address");require(recipient != address(0), "ERC20: transfer to the zero address");_balances[sender] = _balances[sender].sub(amount);_balances[recipient] = _balances[recipient].add(amount);emit Transfer(sender, recipient, amount);}function _mint(address account, uint256 amount) internal {require(account != address(0), "ERC20: mint to the zero address");_totalSupply = _totalSupply.add(amount);_balances[account] = _balances[account].add(amount);emit Transfer(address(0), account, amount);}function _burn(address account, uint256 value) internal {require(account != address(0), "ERC20: burn from the zero address");_totalSupply = _totalSupply.sub(value);_balances[account] = _balances[account].sub(value);emit Transfer(account, address(0), value);}function _approve(address owner, address spender, uint256 value) internal {require(owner != address(0), "ERC20: approve from the zero address");require(spender != address(0), "ERC20: approve to the zero address");_allowances[owner][spender] = value;emit Approval(owner, spender, value);}function _burnFrom(address account, uint256 amount) internal {_burn(account, amount);_approve(account, msg.sender, _allowances[account][msg.sender].sub(amount));}
}
contract ERC20Template is ERC20, ERC20Detailed {constructor() ERC20Detailed("USDT", "USDT", 18) {_mint(msg.sender, 10000000000 * (10 ** uint256(decimals())));}
}

2、编译合约执行 npx hardhat compile

 % npx hardhat compileCompiled 1 Solidity file successfully

3、在test目录下编写测试案例 Token.js

//Chai，这是一个断言库
const { expect } = require("chai");describe("创建合约测试案例", function() {it("CreateContract", async function() {//ethers.js中的Signer 代表以太坊账户对象。 它用于将交易发送到合约和其他帐户。// 在这里，我们获得了所连接节点中的帐户列表，在本例中节点为Hardhat Network，并且仅保留第一个帐户const [owner, addr1, addr2] = await ethers.getSigners();//ethers.js中的ContractFactory是用于部署新智能合约的抽象，因此此处的Token是用来实例代币合约的工厂。const Token = await ethers.getContractFactory("ERC20Template");//在ContractFactory上调用deploy()将启动部署，并返回解析为Contract的Promise。 该对象包含了智能合约所有函数的方法。const hardhatToken = await Token.deploy();//当你调用deploy()时，将发送交易，但是直到该交易打包出块后，合约才真正部署。 调用deployed()将返回一个Promise，因此该代码将阻塞直到部署完成。await hardhatToken.deployed();//查询代币总量const balance = await hardhatToken.balanceOf(await owner.getAddress());console.log("代币总量="+balance)// 给钱包addr1转移100代币数量await hardhatToken.transfer(await addr1.getAddress(), 100);//查询地址addr1余额const balanceAddr1 = await hardhatToken.balanceOf(await addr1.getAddress());console.log("地址addr1余额="+balanceAddr1)// 钱包addr1给钱包addr2转移100代币数量await hardhatToken.connect(addr1).transfer(await addr2.getAddress(), 100);const balanceAddr11 = await hardhatToken.balanceOf(await addr1.getAddress());console.log("余额转移给addr2后地址addr1余额="+balanceAddr11)//查询地址addr2余额const balanceAddr2 = await hardhatToken.balanceOf(await addr2.getAddress());console.log("地址addr2余额="+balanceAddr2)//断言判断expect(await hardhatToken.balanceOf(await addr2.getAddress())).to.equal(100);});
});

执行 npx hardhat test 查看运行结果：

六、部署合约到正式网络网络

1、hardhat.config.js 在此文件里面配置网络信息

require("@nomicfoundation/hardhat-toolbox");
require("@nomiclabs/hardhat-etherscan");module.exports = {networks: {bsc: {url: `https://bsc-dataseed1.ninicoin.io/`,accounts: [`部署合约钱包私钥`],},bscTest: {url: `https://data-seed-prebsc-2-s3.binance.org:8545/`,accounts: [`部署合约钱包私钥`]},hecoTest: {url: 'https://http-testnet.hecochain.com',accounts: [`部署合约钱包私钥`]}},etherscan: {apiKey: {bsc: '',hecoTestnet: '',}},solidity: "0.8.9"
};

2、在scripts目录下创建 TokenDeploy.js 文件

async function main() {const [deployer] = await ethers.getSigners();console.log("获取部署钱包地址:",await deployer.getAddress());console.log("获取部署钱包地址余额:", (await deployer.getBalance()).toString());//指定合约工程要部署的名称const Token = await ethers.getContractFactory("ERC20Template");const token = await Token.deploy();await token.deployed();console.log("部署后合约地址:", token.address);
}main().then(() => process.exit(0)).catch(error => {console.error(error);process.exit(1);});

执行部署命令：npx hardhat run scripts/TokenDeploy.js --network hecoTest

 % npx hardhat run scripts/TokenDeploy.js --network hecoTest获取部署钱包地址: 0xc290436b3da897115493a1547B52783c50f0Bef3
获取部署钱包地址余额: 1138718537000000000
部署后合约地址: 0x9AdAaDb89C6968CF6C4Ef116C614EAedD314a6EE

HECO测试浏览器查看验证

七、合约源代码开源

注：需要申请浏览器 apiKey配置在 hardhat.config.js文件此处。

开源执行命令，成功后就可以在浏览器上查看了。

% npx hardhat verify 0x9adaadb89c6968cf6c4ef116c614eaedd314a6ee --network hecoTest