1-truffle与webjs亲密接触(truffle智能合约项目实战)
在这个实践中,我们将使用Truffle框架创建一个简单的智能合约项目,并通过Web3.js与以太坊区块链进行交互。
首先,确保你已经安装了Node.js和npm。然后,安装Truffle:
npm install -g truffle
创建一个新的Truffle项目:
truffle unbox webpack
在项目目录中,创建一个新的智能合约文件SimpleStorage.sol
:
pragma solidity ^0.5.0;
contract SimpleStorage {
uint public storedData;
constructor(uint initVal) public {
storedData = initVal;
}
function set(uint x) public {
storedData = x;
}
}
编辑2_deploy_contracts.js
文件,部署你的合约:
const SimpleStorage = artifacts.require("SimpleStorage");
module.exports = function(deployer) {
deployer.deploy(SimpleStorage, 100);
};
启动开发网络:
truffle develop
部署合约到网络:
compile
migrate
在src/js
目录下创建一个JavaScript文件,用于与合约交互:
var SimpleStorage = artifacts.require("SimpleStorage");
window.onload = async () => {
if (window.web3) {
const web3 = new Web3(window.web3.currentProvider);
const accounts = await web3.eth.getAccounts();
const simpleStorageInstance = await SimpleStorage.deployed();
document.getElementById('setButton').addEventListener('click', async () => {
const setValue = document.getElementById('setValue').value;
await simpleStorageInstance.set(setValue, { from: accounts[0] });
console.log('Set completed!');
});
document.getElementById('getButton').addEventListener('click', async () => {
const storedData = await simpleStorageInstance.get.call();
console.log('Stored Data: ' + storedData);
});
} else {
console.log('Non-Ethereum browser detected. You should consider trying MetaMask!');
}
};
在HTML文件中,添加按钮和输入框:
<!DOCTYPE html>
<html>
<head>
<title>Simple Storage</title>
</head>
<body>
<h1>Simple Storage</h1>
<p>This is a simple storage contract.</p>
<input id="setValue" type="text" placeholder="Enter a value">
<button id="setButton">Set</button>
<button id="getButton">Get</button>
<script type="text/javascript" src="bundle.js"></script>
</body>
</html>
最后,编译并运行你的DApp:
npm run dev
在浏览器中打开http://localhost:8080
,输入值并点击Set按钮,通过点击Get按钮获取存储的数据。
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