本地开发环境nodejs、web3以太坊合约交互实战
2011 年 7 月 23 日
操作步骤
所有的操作都是在goland里面使用nodejs调web3库
- 编写合约
- 编译合约(web3)-用solc编译(拿到bytecode、abi)
- 部署合约(web3)
- 找到合约实例
- 调用合约(set,get操作)
开发环境
//安装淘宝的镜像 npm install -g cnpm --registry=https://registry.npm.taobao.org //安装指定版本solc cnpm install solc@0.4.24 //安装create-react-app npm install create-react-app -g //创建空的react项目 create-react-app project //进入到project中 npm run start //安装web3 npm i web3 --save
web3模块划分:
- web3-eth:与blockchain合约相关的模块
- web3-shh:与p2p协议广播相关
- web3-bzz: 与swarm存储协议相关
- web3-utils: 开发者工具相关
a.部署合约时候,需要用到提供abi,即可执行后面的动作,进行部署 b.获取合约实例的时候需要用到这个函数,指定abi,指定address
Ganache用于搭建私有网络。在开发和测试环境下,Ganache提供了非常简便的以太坊私有网络搭建方法, 通过可视化界面可以直观地设置各种参数、浏览查看账户和交易等数据
代码加注解
01-deploy
//导入solc编译器 var solc = require('solc') //读取合约 let fs = require('fs') let sourceCode = fs.readFileSync('./contracts/SimpleStorage.sol', 'utf-8') let output = solc.compile(sourceCode, 1) console.log('output:', output) console.log('abi:______',output['contracts'][':SimpleStorage']['interface']) //导出合约 module.exports = output['contracts'][':SimpleStorage']
02-compile
let {bytecode, interface} = require('./01-compile') // console.log('bytecode_____',bytecode) // console.log('interface____',interface) //1.引入web3 let Web3 = require('web3') //2.new一个web3实例 let web3 = new Web3() //3.设置网络 web3.setProvider('http://localhost:7545') console.log('version:________', web3.version) console.log('web3-eth.curretProvider_____________', web3.currentProvider) //此地址需要使用Ganache地址 const account ='0xd4DB91aCBB5Be2a42276567c7473857e14888B53' //1.拼接合约数据interface let contract = new web3.eth.Contract(JSON.parse(interface)) //2.拼接bytecode contract.deploy({ data: bytecode,//合约的bytecode arguments: ['helloworld']//给构造函数传递参数,使用数组 }).send({ from:account, gas:'3000000', gasPrice:'1', }).then(instance =>{ console.log('address:',instance.options.address) })
03-instance
//获取合约实例,导出去 //1.引入web3 let Web3 = require('web3') //2.new一个web3实例 let web3 = new Web3() //3.设置网络 web3.setProvider('http://localhost:7545') let abi = [{ "constant": true, "inputs": [], "name": "getValue", "outputs": [{"name": "", "type": "string"}], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": false, "inputs": [{"name": "_str", "type": "string"}], "name": "setValue", "outputs": [], "payable": false, "stateMutability": "nonpayable", "type": "function" }, { "inputs": [{"name": "_str", "type": "string"}], "payable": false, "stateMutability": "nonpayable", "type": "constructor" }] let address = '0x7a0402FDB3de50eBEBe77F0ff72A6b7526e92447' //此处是合约地址 //此处abi已经json对象,不需要进行parse动作 let contractInstance = new web3.eth.Contract(abi, address) console.log('address__________', contractInstance.options.address) module.exports = contractInstance
04-interaction
//1.导入合约实例 let instance = require('./03-instance') const from = '0xd4DB91aCBB5Be2a42276567c7473857e14888B53' //异步调用,返回值是一个promise //2.读取数据 //整体封装成函数 //web3和区块链交互的返回值都是promise,可以直接使用async let test = async () => { try { let y1 = await instance.methods.getValue().call() let res = await instance.methods.setValue('Hello HangTou').send({ from: from, value: 0, }) console.log('res:', res) let v2 = await instance.methods.getValue().call() console.log('v2:', v2) } catch (e) { console.log(e) } } test()
调用结果
git源码地址 https://github.com/potaxie/web3