Koa2

安装

yarn add koa

代码

Koa的核心代码就三行

const app = new Koa()

app.use(middleware)

app.listen(3000)

const Koa = require('koa')
const app = new Koa()

app.use(async (ctx, next) => {
  ctx.body = 'Hello World!'
})

app.listen(8080)

至此一个简单的服务器运行成功。

koa脚手架

npm install -g koa2-generator

koa2 koa-demo

编写一个静态页面

module.exports = `
  <!DOCTYPE html>
  <html>
    <head>
      <meta charset="utf-8">
      <meta name="viewport" content="width=device-width, initial-scale=1">
      <title>Koa Server HTMl</title>
      <link href="https://cdn.bootcss.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css" rel="stylesheet">
      <script src="https://cdn.bootcss.com/jquery/3.2.0/jquery.min.js"></script>
      <script src="https://cdn.bootcss.com/bootstrap/4.0.0-beta.2/js/bootstrap.bundle.min.js"></script>
    </head>
    <body>
      <div class="container">
        <div class="row">
          <div class="col-md-8">
            <h1>Hi Susan</h1>
            <p>This is a test</p>
          </div>
          <div class="col-md-4">
            <p>测试静态 HTML 页面</p>
          </div>
        </div>
      </div>
    </body>
  </html>

`

View Code

const Koa = require('koa')
const app = new Koa()

const {normal} = require('./tpl/index')

app.use(async(ctx, next) => {
  ctx.type = 'text/html;charset=utf-8;'
  ctx.body =  normal
})

app.listen(8080)

View Code

编写模板页面

安装pug模板引擎

yarn add pug

动态模板引擎代码

module.exports = `
doctype html
html
  head
    meta(charset='utf-8')
    meta(name='viewport=', content='width=device-width, initail-scale=1')
    title Koa Server Pug
    link(href='https://cdn.bootcss.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css',rel='stylesheet')
    script(src='https://cdn.bootcss.com/jquery/3.2.0/jquery.min.js')
    script(src='https://cdn.bootcss.com/bootstrap/4.0.0-beta.2/js/bootstrap.bundle.min.js')
  body
    .container
      .row
        .col-md-8
          h1 Hi #{ name }
          p This is a test
        .col-md-4
          p 测试动态PUG模板引擎

`

View Code

js代码

const Koa = require('koa')
const app = new Koa()

const pug = require('pug')

const {pugTpl} = require('./tpl/index')

app.use(async(ctx, next) => {
  ctx.type = 'text/html;charset=utf-8;'
  ctx.body =  pug.render(pugTpl, {
    name: 'Susan'
  })
})

app.listen(8080)

View Code

使用模板引擎中间件，支持ejs，pug

koa-views

pug模板引擎代码

doctype html
html
  head
    meta(charset='utf-8')
    meta(name='viewport=', content='width=device-width, initail-scale=1')
    title Koa Server Pug
    link(href='https://cdn.bootcss.com/bootstrap/4.0.0-beta.2/css/bootstrap.min.css',rel='stylesheet')
    script(src='https://cdn.bootcss.com/jquery/3.2.0/jquery.min.js')
    script(src='https://cdn.bootcss.com/bootstrap/4.0.0-beta.2/js/bootstrap.bundle.min.js')
  body
    .container
      .row
        .col-md-8
          h1 Hi #{ name }
          p This is a test
        .col-md-4
          p 测试动态PUG模板引擎

View Code

js代码

const Koa = require('koa')
const app = new Koa()
const views = require('koa-views')
const {resolve} = require('path')

app.use(views(resolve(__dirname, './views'), {
  extension: 'pug'
}))

app.use(async(ctx, next) => {
  await ctx.render('index', {
    name: 'Susan'
  })
})

app.listen(8080, () => {
  console.log('http://localhost:8080')
})

View Code

koa-router

yarn add koa-router

代码

const router = require('koa-router')()

router.get('/news', async (ctx, next) => {
  ctx.body  = '路由'
})

router.get('/news/:id', async (ctx, next) => {
  ctx.body = '动态路由'
})

app.use(router.routes())

View Code

路由分离

代码

const router = require('koa-router')()

router.prefix('/user')

router.get('/', async ctx => {
  ctx.body = 'Hello Koa2'
})

router.get('/info', async ctx => {
  ctx.body = 'Hello UserInfo'
})

module.exports = router

View Code

const user = require('./routes/user')

app.use(user.routes()).use(user.allowedMethods())

View Code

GET

通过ctx.query/ctx.querystring/ctx.request.query/ctx.request.querystring

代码

router.get('/news', async (ctx, next) => {
  console.log('ctx.query', ctx.query)
  console.log('ctx.querystring', ctx.querystring)
  console.log('ctx.request.query', ctx.request.query)
  console.log('ctx.request.querystring', ctx.request.querystring)
})

View Code

curl i http://localhost:3000/news?name='Susan&age=12'

POST

通过koa-body

const koaBody = require('koa-body')

app.use(koaBody())

router.post('/doAction', async ctx => {
  console.log('ctx.request.body', ctx.request.body)
})

View Code

curl i http://localhost:3000/doAction -d 'name=Susan,age=20'

静态资源

安装koa-static

代码

const server = require('koa-static')

app.use(server(resolve(__dirname, './static')))

router.get('/', async ctx => {
  await ctx.render('index')
})

View Code

<link href="css/style.css" rel="stylesheet" />

<img src="img/1.jpg"/>

<script src="js/index.js"></script>

View Code

Cookie

ctx.cookies.set(name, value, [options])

ctx.cookies.get(name)

如何处理中文

使用Buffer转换

// 将中文转换base64字符串
new Buffer(value).toString('base64')
// 将base64字符串转换为中文
new Buffer(value, 'base64').toString()

Session

安装koa-session

const session = require('koa-session')

app.keys = ['some secret hurr']
const CONFIG = {
  key: 'koa:sess', 
  maxAge: 86400000,
  autoCommit: true, 
  overwrite: true, 
  httpOnly: true, 
  signed: true, 
  rolling: false, 
  renew: false
}

app.use(session(CONFIG, app))

router.get('/', async ctx => {
  let n = ctx.session.view || 0
  ctx.session.view = ++ n
  ctx.body = n
})

View Code

Mongodb

https://www.mongodb.com/download-center?jmp=nav#community

操作数据库

http://mongodb.github.io/node-mongodb-native/

安装mongodb

连接数据库，创建集合，插入数据

const MongoClient = require('mongodb').MongoClient
const url = 'mongodb://127.0.0.1:27017'  // URL
const dbName = 'dbs' // 数据库名称
const client = new MongoClient(url)  // 创建一个Mongodb Client

client.connect(err=>{ // 连接数据库
  if (err) return 
  console.log('Connected successfully to server')
  const db = client.db(dbName) 
  // 插入数据
  db.collection('documents').insertMany([
    {a:1},
    {b:2},
    {c:3}
  ])
  db.collection('documents').insertOne(
    {d:4}
  )
  client.close()
})

View Code

查找数据

db.collection('documents').find({})
  .toArray((err, docs) => {
    if (err) return 
    console.log(docs)
  })

更新数据

db.collection('documents')
  .updateOne({a:1}, {$set: {a: 100}}, (err, res) => {
    if (err) return 
    console.log(res)
  })

db.collection('documents')
  .updateMany({a:1}, {$set: {a: 100}}, (err, res) => {
    if (err) return 
    console.log(res)
  })

删除数据

db.collection('documents')
  .deleteOne({a:10}, (err, res) => {
    if (err) return 
    console.log(res)
  })

Robo 3T

https://robomongo.org/

Mongoose

https://mongoosejs.com/docs/api.html

连接数据库

首先配置数据库，创建一个dbs的数据库

module.exports = {
  dbs:'mongodb://127.0.0.1:27017/dbs'
}

数据库创建完毕，那么创建model也就是集合，即表

const mongoose = require('mongoose') 

let personSchema = new mongoose.Schema({
  name: String,
  age: Number
})

module.exports = mongoose.model('Person', personSchema)

数据库和表创建完毕，那么开始连接数据库

const mongoose = require('mongoose')
const dbConfig = require('./dbs/config')

mongoose.connect(dbConfig.dbs, {
  useNewUrlParser: true
})

此刻数据库连接成功，那么我们开始

添加数据

router.post('/addPerson', async ctx => {
  const person = new Person({
    name: ctx.request.body.name,
    age: ctx.request.body.age
  })
  let code
  try {
    await person.save()
    code = 0
  } catch (error) {
    code = 1
  }
  ctx.body = {
    code
  }
})

查询数据

const res = await Person.findOne({name:ctx.request.body.name})
const ress = await Person.find({name: ctx.request.body.name})

更新数据

const result = await Person.where({
  name: ctx.request.body.name
}).update({
  age:ctx.request.body.age
})

删除数据

const result = await Person.where({
  name: ctx.request.body.name
}).remove()

Redis

访问网页服务器端会在客户端设置cookie保存session

每次请求把cookie中session发送到服务器端

服务端用session保存客户端状态

服务器端会把session的值保存到Redis中

浏览器用cookie保存session

而且Redis是一个非常快速的读写数据库

案例：登录校验

安装

https://github.com/MicrosoftArchive/redis/releases

启动Redis

安装koa中间件操作Redis

yarn add koa-generic-session koa-redis

连接Redis

app.keys=['keys','keyskeys'] // session加密处理，随便两个值
app.use(session({
  key:'mt',
  prefix:'mtpr',
  store: new Redis(),
}))

使用session

ctx.session.count++

我们也可以直接对Redis操作

const Store = new Redis().client

const st = await Store.hset('fix', 'name', Math.random())

使用redis-cli.exe查看数据

key *

get

hset

hget