基于区块链的云笔记小程序开发（二）

接着上一步骤，继续开发

今天任务：

• 搭建node服务端
• 通过web3.js实现与以太坊的交互
• 安装节点工具Ganache，来搭建私有链节点
• 利用postman测试接口

目录结构：

搭建node服务端（server.js）

var http = require("http");
var url = require("url");
var querystring = require('querystring');

function start(route, handle) {
    function onRequest(request, response) {
        
        var pathname = url.parse(request.url).pathname;
        var body = '';
        //每当接收到请求体数据，累加到post中
        request.on('data', function (chunk) {
            body += chunk;  //一定要使用+=，如果body=chunk，因为请求favicon.ico，body会等于{}
        });
        //async、await处理异步请求
        request.on('end', async function () {
            // 解析参数
            body = querystring.parse(body);  //将一个字符串反序列化为一个对象
            //返回json数据，并解决跨域问题
            response.writeHead(200, { "Content-Type": "text/json","Access-Control-Allow-Origin":"*"});
            var content = await route(handle, pathname, body);
            response.write(JSON.stringify(content));
            response.end();
        });

    }
    http.createServer(onRequest).listen(9999);
    console.log("Server has started..");
}

exports.start = start;

通过web3.js实现与以太坊的交互（requestHandler.js）

//测试
function test(body) {
    return 'result';
}

//创建账户
async function newAccount(body) {
    var account = "account";
    // console.log(body.password);
    await web3.eth.personal.newAccount(body.password, function (error, data) {
        console.log("创建的新账户地址：" + data)
        account = data;
    });
    sendToAccount(account, '10');
    return account;
}

//转账给用户
async function sendToAccount(account, amount) {
    var result =await unlockAccount(adminAccount, adminPassword);
    if (result) {//解锁管理员账户
        web3.eth.sendTransaction({
            from: adminAccount,
            to: account,
            value: web3.utils.toWei(amount)
        }, function (error, data) {
            console.log("交易的hash值：" + data);
        });
    }
}

//解锁账户
async function unlockAccount(account, password) {
    var result = false;
    await web3.eth.personal.unlockAccount(account, password, 300, function (error, data) {
        console.log(account + "解锁结果：" + data);
        result = data;
    });
    return result;
}

//部署合约方法的转发，因为没有返回值，server.js中会报错
async function deploy(body) {
    var account = body.account;
    var password = body.password;
    console.log(account);
    var address = await deployContract(account);
    console.log("address:"+address);
    return {'contractAddress':address};
}

//部署合约  
function deployContract(account) {
    return new Promise(function (resolve, reject) {
        bn.deploy({
            data: bytecode
        }).send({
            from: account,
            gas: 3000000,
            gasPrice: '300000000000'
        }, function (error, data) {
            //data:交易的哈希值
            console.log(error);
            console.log(data);
        }).on('receipt', function (receipt) {
            console.log('合约的地址：' + receipt.contractAddress) // contains the new contract address
            //contractAddress = receipt.contractAddress;//TODO 异步的问题
            resolve(receipt.contractAddress);
        });
    });
    //return contractAddress;
}

//添加笔记
async function addNote(body) {
    var title = body.title;
    var desc = body.desc;
    var content = body.content;
    var account = body.account;
    var password = body.password;
    var date = getNowFormatDate();
    var id = web3.utils.sha3(new Date().getTime() + title + desc + content);
    var contractAddress = body.contractAddress;

    var result = await unlockAccount(account, password);
    if (result) {//解锁当前用户的以太坊账户
        bn.options.address = contractAddress;
        bn.methods.addNote(date, id, title, desc, content).send({
            from: account
        }, function (error, data) {
            //data:调用方法之后的返回值
            return 'success';
        });
    }
}

//获得笔记列表
async function getNoteList(body) {
    var date = body.date;
    var count = body.count;
    var account = body.account;
    var password = body.password;
    var contractAddress = body.contractAddress;
    var result = await unlockAccount(account, password);
    if (result) {//解锁当前用户的以太坊账户
        bn.options.address = contractAddress;
        bn.methods.getNodeList(date, count).call({
            from: account
        }, function (error, data) {
            //data:调用方法之后的返回值
        });
    }
}

//获得一个笔记
async function getNote(body) {
    var date = body.date;
    var id = body.id;
    var account = body.account;
    var password = body.password;
    var contractAddress = body.contractAddress;
    var result = await unlockAccount(account, password);
    if (result) {//解锁当前用户的以太坊账户
        bn.options.address = contractAddress;
        bn.methods.getNode(date, id).call({
            from: account
        }, function (error, data) {
            //data:调用方法之后的返回值
        });
    }
}

//获取当前时间，格式YYYY-MM-DD
function getNowFormatDate() {
    var date = new Date();
    var seperator1 = "-";
    var year = date.getFullYear();
    var month = date.getMonth() + 1;
    var strDate = date.getDate();
    if (month >= 1 && month <= 9) {
        month = "0" + month;
    }
    if (strDate >= 0 && strDate <= 9) {
        strDate = "0" + strDate;
    }
    var currentdate = year + seperator1 + month + seperator1 + strDate;
    return currentdate;
}

exports.test = test;
exports.newAccount = newAccount;
exports.deploy = deploy;
exports.addNote = addNote;
exports.deployContract = deployContract;

安装节点工具Ganache，搭建私有链节点

传送门：https://truffleframework.com/ganache

ganache提供了10个测试账户，并且每个账户都有100个以太币，便于测试

这里我用第一个进行测试

首先，将web3请求的地址改为私有链节点的地址（requestHandle.js）

const web3 = new Web3(new Web3.providers.HttpProvider('http://127.0.0.1:7545'));

私有链节点地址可以在ganache上方查看

启动node服务端

 

利用postman测试接口

测试test方法，返回"result"，说明可以正常访问nodejs服务端。

其他方法陆续进行测试，这里就不多说明。