本文转自:https://www.cnblogs.com/zhongweiv/p/nodejs_koa2_webapp.html
目录
前言
前面一有写到一篇Node.js+Express构建网站简单示例:http://www.cnblogs.com/zhongweiv/p/nodejs_express_webapp.html
这篇还是用以前的例子, 用Node.js+Koa2构建
Koa: https://github.com/koajs/koa
http://koa.bootcss.com (中文)
Koa就不多介绍了,前面也写过Express,同一个团队打造,前面也过express文章,对比着看,自然可以看出些优点!
搭建项目及其它准备工作
CREATE DATABASE IF NOT EXISTS nodesample CHARACTER SET UTF8;USE nodesample;SET FOREIGN_KEY_CHECKS=0;DROP TABLE IF EXISTS `userinfo`; CREATE TABLE `userinfo` (`Id` int(11) NOT NULL AUTO_INCREMENT COMMENT '主键',`UserName` varchar(64) NOT NULL COMMENT '用户名',`UserPass` varchar(64) NOT NULL COMMENT '用户密码',PRIMARY KEY (`Id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='用户信息表';
安装koa-generator: https://github.com/17koa/koa-generator
npm install -g koa-generator
安装成功后下图(版本:1.1.16)
然后创建Koa2项目,安装相关依赖项
cd 工作目录 koa2 项目名 cd 项目目录 && npm install
1.安装使用MySQL需要的包
npm install --save mysql
没有使用过的可以看我以前写的相关操作文章:http://www.cnblogs.com/zhongweiv/p/nodejs_mysql.html
2.安装ejs(koa2默认为jade,我习惯使用ejs)
npm install --save ejs
没有使用过的可以看我以前写的相关操作文章:http://www.cnblogs.com/zhongweiv/p/nodejs_express.html
3.安装Session存储相关包(存储到redis)
npm install koa-session https://github.com/koajs/session
npm install --save koa-session
koa-session-redis https://github.com/Chilledheart/koa-session-redis
npm install --save koa-session-redis
1.删除掉创建项目后自带的views和routes下的文件
2.重新规划项目目录,规划后如下
目录规则解释:
1.新增pub目录:主要为了统一存放"数据访问"、"业务逻辑"、"公共方法文件"、"数据库帮助文件"、"配置文件"等
2.新增pub目录下utils目录:主要为了统一存放类似"公共函数文件"、"返回值文件"、"枚举文件"等公共文件
3.新增pub目录下config目录:主要为了统一存放各种类型的配置文件
4.新增pub目录下db目录:主要为了统一存放各种数据库帮助类,比如:"mysql-helper.js"、"mongo-helper.js"等等
5.新增pub目录下model目录:主要为了统一存放各种数据库各表CURD操作
6.新增pub目录下bll目录:主要为了统一存放各种业务逻辑的具体实现
配置文件
从上面的图可以看出,我在pub下新建的config目录下新建了一个config.js
这个config.js中将编写“开发环境”和“发布环境”中所需的配置,代码如下
/*** 配置文件*/ //发布配置 const production = {//服务器端口SERVER_PORT : 3000,//REDIS配置REDIS: {host: 'localhost', port: 6379,password: "abcd",maxAge: 3600000},//MYSQL数据库配置MYSQL: {host: "localhost",user: "root",password: "abcd",port: "3306",database: "nodesample",supportBigNumbers: true,multipleStatements: true,timezone: 'utc'}}//开发配置 const development = {//服务器端口SERVER_PORT : 3000,//REDIS配置REDIS: {host: 'localhost', port: 6379,password: "abcd",maxAge: 3600000},//MYSQL数据库配置MYSQL: {host: "localhost",user: "root",password: "abcd",port: "3306",database: "nodesample",supportBigNumbers: true,multipleStatements: true,timezone: 'utc'}}const config = developmentmodule.exports = config
规划示例路由,并新建相关文件
示例中将有注册、登录功能,先规划好路由,新建routes、views下的相关需要的文件(如项目目录图中文件),并修改app.js文件
const Koa = require('koa') const app = new Koa() const views = require('koa-views') const json = require('koa-json') const onerror = require('koa-onerror') const bodyparser = require('koa-bodyparser') const logger = require('koa-logger')const config = require('./pub/config/config.js'); const session = require('koa-session'); const RedisStore = require('koa2-session-redis');const index = require('./routes/index') const reg = require('./routes/reg') const login = require('./routes/login') const logout = require('./routes/logout')// error handler onerror(app)// middlewares app.use(bodyparser({enableTypes:['json', 'form', 'text'] })) app.use(json()) app.use(logger()) app.use(require('koa-static')(__dirname + '/public'))app.use(views(__dirname + '/views', {extension: 'ejs' }))// logger app.use(async (ctx, next) => {const start = new Date()await next()const ms = new Date() - startconsole.log(`${ctx.method} ${ctx.url} - ${ms}ms`) })app.keys = ['Porschev']; const redis_conf = { key: 'Porschev',maxAge: config.REDIS.maxAge,overwrite: true,httpOnly: true, rolling: false,sign: true,store: new RedisStore({host: config.REDIS.host,port: config.REDIS.port, password: config.REDIS.password }) };app.use(session(redis_conf, app));// routes app.use(index.routes(), index.allowedMethods()) app.use(reg.routes(), reg.allowedMethods()) app.use(login.routes(), login.allowedMethods()) app.use(logout.routes(), logout.allowedMethods())// error-handling app.on('error', (err, ctx) => {console.error('server error', err, ctx) });app.listen(config.SERVER_PORT, () => {console.log(`Starting at port ${config.SERVER_PORT}!`) });module.exports = app
注意看红色标记修改或增加的部分
实现数据访问和业务逻辑相关方法
1.首先编写一个mysql-helper.js方便以连接池的方式进行操作
const config = require('./../config/config.js') const mysql = require("mysql")const pool = mysql.createPool(config.MYSQL)let query = function(sql, args) {return new Promise((resolve, reject) => {pool.getConnection(function(err, connection) {if (err) {resolve(err)} else {connection.query(sql, args, (err, result) => {if (err) {reject(err)} else {resolve(result)}connection.release()})}})})}module.exports = { query }
2.编写数据访问相关方法(model目录下的userinfo.js),如下
const mysqlHelper = require('./../db/mysql-helper.js')const userinfo = {/*** 增加一条数据* @param {object} args 参数* @return {object} 结果*/async add ( args ) {let sql = 'INSERT INTO userinfo(UserName, UserPass) VALUES(?, ?)'let params = [args.username, args.userpass]let result = await mysqlHelper.query(sql, params)return result},/*** 根据UserName得到一条数据* @param {object} args 参数* @return {object} 结果*/async getByUserName( args ){let sql = 'SELECT Id, UserName, UserPass FROM userinfo WHERE UserName = ?'let params = [args.username]let result = await mysqlHelper.query(sql, params)return result},/*** 根据UserName得到数量* @param {object} args 参数* @return {object} 结果*/async getCountByUserName( args ){let sql = 'SELECT COUNT(1) AS UserNum FROM userinfo WHERE UserName = ?'let params = [args.username]let result = await mysqlHelper.query(sql, params)return result},}module.exports = userinfo
3.在写业务逻辑之前先规划好返回值(utils目录下retcode.js)
/** 返回码*/ const RetCode = {SessionExpired: -1, //session过期Fail: 0, //失败Success: 1, //成功ArgsError: 2, //参数错误UserExisted: 10, //用户已经存在UsernameOrPasswordError: 11, //用户名或者密码错误 UserNotExist: 12, //用户不存在 };module.exports = RetCode
4.编写“登录”、“注册”等业务逻辑(bll下userinfo.js)
const usermodel = require('./../model/userinfo.js') const retCode = require('./../utils/retcode.js')const userinfo = {/*** 注册* @param {object} ctx 上下文* @return {object} 结果*/async register ( ctx ) {let form = ctx.request.bodyconst args = {username: form.username,userpass: form.userpass}let result = {code: retCode.Success, data: null}//验证非空if(!args.username || !args.userpass){result.code = retCode.ArgsError return result}//根据用户名得到用户数量let userNumResult = await usermodel.getCountByUserName(args)//用户名已被注册if(userNumResult[0].UserNum > 0){result.code = retCode.UserExisted return result}//插入注册数据let userResult = await usermodel.add(args)if(userResult.insertId <= 0){result.code = retCode.Fail return result}return result},/*** 登录* @param {object} ctx 上下文* @return {object} 结果*/async login ( ctx ) {let form = ctx.request.bodyconst args = {username: form.username,userpass: form.userpass}let result = {code: retCode.Success, data: null}//验证非空if(!args.username || !args.userpass){result.code = retCode.ArgsError return result}//根据用户名得到用户信息let userResult = await usermodel.getByUserName(args)//用户不存在if(userResult.length == 0){result.code = retCode.UserNotExist return result}//用户名或密码错误if(userResult[0].UserName != args.username || userResult[0].UserPass != args.userpass){result.code = retCode.UsernameOrPasswordError return result}//将用户ID存入Session中ctx.session = {id: userResult[0].Id}return result},}module.exports = userinfo
注册
1.views目录下reg.ejs
<html> <head> <title>Nodejs学习笔记(十五)--- Node.js + Koa2 构建网站简单示例</title> </head> <body> <h1><%= title %></h1> 登录名:<input type="text" id="txtUserName" maxlength="20" /> <br/> <br/> 密码:<input type="password" id="txtUserPwd" maxlength="12" /> <br/> <br/> 密码:<input type="password" id="txtUserRePwd" maxlength="12" /> <br/> <br/> <input type="button" id="btnSub" value="注册" /> </body> </html><script src="/javascripts/jquery-1.11.2.min.js" type="text/javascript"></script> <script src="/javascripts/md5.js" type="text/javascript"></script><script type="text/javascript"> $(function(){$('#btnSub').on('click', function(){var $txtUserName = $('#txtUserName'),txtUserNameVal = $.trim($txtUserName.val()),$txtUserPwd = $('#txtUserPwd'),txtUserPwdVal = $.trim($txtUserPwd.val()),$txtUserRePwd = $('#txtUserRePwd'),txtUserRePwdVal = $.trim($txtUserRePwd.val());if(txtUserNameVal.length == 0){alert('用户名不能为空'); return false;}if(txtUserPwdVal.length == 0){ alert('密码不能为空'); return false;}if(txtUserRePwdVal.length == 0){alert('重复密码不能为空'); return false;}if(txtUserPwdVal != txtUserRePwdVal){ alert('两次密码不一致'); return false;}$.ajax({url: '/reg',type: 'POST',dataType: 'json',data: {username: txtUserNameVal, userpass: hex_md5(txtUserPwdVal) },beforeSend: function (xhr) {},success: function (res) {if (res != null && res.code) {var retVal = parseInt(res.code);switch (retVal) {case 2:alert('输入有误');break;case 0:alert('注册失败');break;case 1:alert('注册成功!');location.href = '/login' break;case 10:alert('用户已注册');break; }}else {alert('操作失败');}},complete: function (XMLHttpRequest, textStatus) {},error: function (XMLHttpRequest, textStatus, errorThrown) {alert('操作失败');}}); })});</script>
2.routes目录下reg.js
const router = require('koa-router')() const userBll = require('./../pub/bll/userinfo.js') const title = '注册'router.prefix('/reg')router.get('/', async (ctx, next) => {await ctx.render('reg', { title }) })router.post('/', async (ctx, next) => {let result = await userBll.register(ctx)ctx.body = result;})module.exports = router
登录
1.views目录下login.ejs
2.routes目录下login.js
const router = require('koa-router')() const userBll = require('./../pub/bll/userinfo.js') const title = '登录'router.prefix('/login')router.get('/', async (ctx, next) => {await ctx.render('login', { title }) })router.post('/', async (ctx, next) => {let result = await userBll.login(ctx);ctx.body = result;})module.exports = router
首页
1.views目录下index.ejs
<html> <head> <title>Nodejs学习笔记(十五)--- Node.js + Koa2 构建网站简单示例</title> </head> <body> <h1><%= title %></h1><% if(id != null) {%><h3>登录用户ID:<%= id %> <a id="btnLogOut" href="javascript:void(0);">安全退出</a></h3> <% } %> </body> </html><script src="/javascripts/jquery-1.11.2.min.js" type="text/javascript"></script><script type="text/javascript"> $(function(){$('#btnLogOut').on('click', function(){if(!confirm('确认要退出吗?')){return;}$.ajax({url: '/logout',type: 'POST',dataType: 'json',data: {},beforeSend: function (xhr) {},success: function (res) {if (res != null && res.code) {var retVal = parseInt(res.code);switch (retVal) { case 0:alert('失败');break;case 1:alert('成功!');location.href = '/login' break; }}else {alert('操作失败');}},complete: function (XMLHttpRequest, textStatus) {},error: function (XMLHttpRequest, textStatus, errorThrown) {alert('操作失败');}}); })});</script>
2.routes目录下index.js
const router = require('koa-router')() const title = '首页'router.get('/', async (ctx, next) => { //判断登录if(!ctx.session || !ctx.session.id){await ctx.redirect('/login') }else{ const id = ctx.session.id;await ctx.render('index', { title, id })} })module.exports = router
index.js文件中实现如果不存在session则跳回登录页
安全退出
1.routes目录下logout.js
const router = require('koa-router')() const retCode = require('./../pub/utils/retcode.js')router.prefix('/logout')router.get('/', async (ctx, next) => {await ctx.render('logout', {}) })router.post('/', async (ctx, next) => {ctx.session = null;let result = {code: retCode.Success, data: null}ctx.body = result;})module.exports = router
写在之后
没有去说一些细节API,写这篇主要可以对比 Nodejs学习笔记(七)--- Node.js + Express 构建网站简单示例 来看,完全是一亲的示例,只是这次用的Koa2,方便大家看看Koa2和express写出来的不同
总的来说Koa2还是比较好上手,async、await这个对于有C#语言基础的来说也比较亲切,不用二次理解
可以对比一下express时的各种嵌套回调写法,Koa2写好更优雅、更易阅读
示例有限,其它操作通过官网查找API或github找一些组件来动手试,比如最常用的一些功能:操作cookies、上传文件、session存储到其它介质等
参考资料: https://koa.bootcss.com/
老规矩不放源码,虽然是示例结构,但是尽量按照平常做项目的想法去实现的,有兴趣的动手去搭项目做才会理解一些思路,代码都放在文章中了,有问题留言^_^!
作 者: Porschev[钟慰]
出 处: http://www.cnblogs.com/zhongweiv/
微 博: http://weibo.com/porschev
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