关于javascript:前端培训中级阶段52-Express-的安装使用-Express-完成-RESTful-操作-MongoDB

前端最根底的就是 HTML+CSS+Javascript。把握了这三门技术就算入门，但也仅仅是入门，当初前端开发的定义曾经远远不止这些。前端小课堂（HTML/CSS/JS），本着晋升技术水平，打牢基础知识的中心思想，咱们开课啦（每周四）。

当咱们须要起一个服务器时，我猜大多数人的抉择是 Express （至多我看到的一些小工具是）。

明天咱们来装置一下，而后联合上节课操作一下 MongoDB 。

Express

装置

npm install express --save

依赖还是蛮好装的，装好依赖咱们就能够启动咱们的服务了。

var express = require('express')var app = express()var server = app.listen(8088, () => {    var host = server.address().address;    var port = server.address().port;    console.log('Example app listening at ', host, port);    console.log('author: lilnong.top');})app.use(function(req, res, next){    res.send('www.lilnong.top')    next();})

应用

监听路由、中间件

中间件，监听所有申请类型

app.use(function(req, res, next){    console.log('use-1', req.ip)    next();})

中间件，监听 /api 下的所有申请类型

app.use('/api', function(req, res, next){    console.log('use-2-/api', req.ip)    next();})

监听 /api 下 GET 申请类型

app.get('/api', function(req, res, next){    console.log('use-2-/api', req.ip)    next();})

监听 /api 下所有申请类型

app.all('/api',function(req, res, next){    console.log('/api-all', req.ip)    next();})

RESTful 实现 CURD

默认 express 是不会解析 post 申请的 body。咱们须要减少一个中间件

app.use(express.json());app.use(express.urlencoded({ extended: false }));

标准

// GET /task 获取 task 列表// GET /task/:id 查看某个具体的 task// POST /task 新建一个 task// PUT /task/:id 更新 id 为 12 的 task// DELETE /task/:id 删除 id 为 12 的 task

实现代码

const taskrouter = express.Router()taskrouter.route('/task')    .post(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)        let data = await dbo.collection('user').insert({...req.body,author: 'www.lilnong.top', time: new Date(), uuid: `${Date.now()}-${Math.random()}-${Math.random()}-${Math.random()}`})        res.send(data)                // fetch(`/restful-api/task`,{        //     method: 'post',        //     body: new URLSearchParams({cdate: new Date().toLocaleString()}),         // })        //     .then(v=>v.json())        //     .then(v=>console.log('post restful-api/task',v))    })    .get(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)        let data = await dbo.collection('user').find().toArray()        res.send(data)        // fetch(`/restful-api/task`)        //     .then(v=>v.json())        //     .then(v=>console.log('get restful-api/task',v))    })taskrouter.route('/task/:uuid')    .get(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)        let data = await dbo.collection('user').find({uuid: req.params.uuid}).toArray()        res.send(data)                // fetch(`/restful-api/task/1604050499531-0.7571477556104735-0.2684691266146757-0.455850836469736`)        //     .then(v=>v.json())        //     .then(v=>console.log('get restful-api/task/1604050499531-0.7571477556104735-0.2684691266146757-0.455850836469736',v))    })    .put(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)                let data = await dbo.collection('user').updateOne({uuid: req.params.uuid},{$set: {...req.body,utime: new Date()}})        res.send(data)                // fetch(`/restful-api/task/1604050500761-0.5377497291744571-0.022071316247671557-0.336347246286103`,{        //     method: 'put',        //     body: new URLSearchParams({udate: new Date().toLocaleString(), uauthor: 'www.lilnong.top'}),         // })        //     .then(v=>v.json())        //     .then(v=>console.log('put restful-api/task',v))    })    .delete(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)                let data = await dbo.collection('user').deleteOne({uuid: req.params.uuid})        res.send(data)        // fetch(`/restful-api/task/1604050496565-0.660805544561031-0.5097297478722462-0.41065424039611176`,{        //     method: 'delete',        // })        //     .then(v=>v.json())        //     .then(v=>console.log('delete restful-api/task/1604050496565-0.660805544561031-0.5097297478722462-0.41065424039611176',v))    })app.use('/restful-api', taskrouter)

demo 代码

let dbovar MongoClient = require('mongodb').MongoClient;MongoClient.connect(    'mongodb://localhost:27017/sf-mongodb',    {},    async function(err, db){        if(err){            reject(err)            return console.error(err)        }        dbo = db.db('sf-mongodb');        console.log('mongodb-success')    })var express = require('express')var app = express()var server = app.listen(process.env.NODE_EXPRESS_MONGODB || 23456, () => {    var host = server.address().address;    var port = server.address().port;    console.log('Example app listening at ', host, port);    console.log('author: lilnong.top');})app.use(express.json());app.use(express.urlencoded({ extended: false }));app.use(function(req, res, next){    console.log('header', req.ip)    next();})app.use('/api',function(req, res, next){    console.log('/api', req.ip)    next();})app.get('/api',function(req, res, next){    console.log('/api-get', req.ip)    next();})app.all('/api',function(req, res, next){    console.log('/api-all', req.ip)    next();})// GET /task 获取 task 列表// GET /task/:id 查看某个具体的 task// POST /task 新建一个 task// PUT /task/:id 更新 id 为 12 的 task// DELETE /task/:id 删除 id 为 12 的 taskconst taskrouter = express.Router()taskrouter.route('/task')    .post(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)        let data = await dbo.collection('user').insert({...req.body,author: 'www.lilnong.top', time: new Date(), uuid: `${Date.now()}-${Math.random()}-${Math.random()}-${Math.random()}`})        res.send(data)                // fetch(`/restful-api/task`,{        //     method: 'post',        //     body: new URLSearchParams({cdate: new Date().toLocaleString()}),         // })        //     .then(v=>v.json())        //     .then(v=>console.log('post restful-api/task',v))    })    .get(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)        let data = await dbo.collection('user').find().toArray()        res.send(data)        // fetch(`/restful-api/task`)        //     .then(v=>v.json())        //     .then(v=>console.log('get restful-api/task',v))    })taskrouter.route('/task/:uuid')    .get(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)        let data = await dbo.collection('user').find({uuid: req.params.uuid}).toArray()        res.send(data)                // fetch(`/restful-api/task/1604050499531-0.7571477556104735-0.2684691266146757-0.455850836469736`)        //     .then(v=>v.json())        //     .then(v=>console.log('get restful-api/task/1604050499531-0.7571477556104735-0.2684691266146757-0.455850836469736',v))    })    .put(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)                let data = await dbo.collection('user').updateOne({uuid: req.params.uuid},{$set: {...req.body,utime: new Date()}})        res.send(data)                // fetch(`/restful-api/task/1604050500761-0.5377497291744571-0.022071316247671557-0.336347246286103`,{        //     method: 'put',        //     body: new URLSearchParams({udate: new Date().toLocaleString(), uauthor: 'www.lilnong.top'}),         // })        //     .then(v=>v.json())        //     .then(v=>console.log('put restful-api/task',v))    })    .delete(async (req,res,next) => {        console.log(req.method, req.url, req.params, req.query, req.body)                let data = await dbo.collection('user').deleteOne({uuid: req.params.uuid})        res.send(data)        // fetch(`/restful-api/task/1604050496565-0.660805544561031-0.5097297478722462-0.41065424039611176`,{        //     method: 'delete',        // })        //     .then(v=>v.json())        //     .then(v=>console.log('delete restful-api/task/1604050496565-0.660805544561031-0.5097297478722462-0.41065424039611176',v))    })app.use('/restful-api', taskrouter)app.use(function(req, res, next){    console.log('footer', req.ip)    res.send('www.lilnong.top')    next();})