express框架下使用session的方法

// app.js
// 引入express-session
var session = require('express-session')
// 为应用绑定session中间件
app.use(session({
  name: 'session-id',
  secret: '12345-67890',
  saveUninitialized: false,
  resave: false
}))

router.get('/session/first', (req, res, next) => {
 let s = req.session
 console.log(s)
 res.send(s)
})

router.get('/session/view', (req, res, next) => {
 let s = req.session
 if (req.session.views) {
  req.session.views++
  res.send(`views: ${req.session.views} time.`)
 } else {
  req.session.views = 1
  res.send('views: 0')
 }
})

npm i express-session session-file-store

// app.js
var session = require('express-session')
var FileStore = require('session-file-store')(session) // 引入 
// 在express-session中使用
app.use(session({
 name: 'session-id',
 secret: '12345-67890',
 saveUninitialized: false,
 resave: false,
 store: new FileStore() // 指明使用文件存储
}))

// app.js
const mongoose = require('mongoose')
const url = 'mongoodb://localhost:27017/confusion'
const connect = mongoose.connect(url, {useNewUrlParser: true, useCreateIndex: true})
connest.then(db => {
 console.log('Connect correct to server')
}, err => {console.log(err)})

// @/models/user.js
var mongoose = require('mongoose'),
Schema = mongoose.Schema,
User = new Schema({
 username: {
  type: String,
  required: true,
  unique: true
 },
 password: {
  type: String,
  required: true
 },
 admin: {
  type: Boolean,
  default: false
 }
})
module.exports = mongoose.model('User', User)

注册的接口
  是否已经存在用户------存在------>不重复创建. 
      |-----------不存在----->创建用户

// @/routes/users.js
// /session/first /session/view 注释了或删除了。
// 该文件在app.user(session(...))之前，所以得不到req.session
// // 查看session
// router.get('/session/first', (req, res, next) => {
//  let s = req.session
//  console.log(s)
//  res.send(s)
// })
// // 在session里保存浏览次数
// router.get('/session/view', (req, res, next) => {
//  let s = req.session
//  if (req.session.views) {
//   req.session.views++
//   res.send(`views: ${req.session.views} time.`)
//  } else {
//   req.session.views = 1
//   res.send('views: 1')
//  }
// })

router.post('/signup', (req, res, next) => {
 console.log(req.body)
 User.findOne({username: req.body.username}).then(user => {
  if (user === null) {
   return User.create({
    username: req.body.username,
    password: req.body.password
   })
  } else {
   var err = new Error(`User ${req.body.username} already exist!`)
   err.status = 403
   next(err)
  }
 }).then(user => {
  res.statusCode = 200
  res.json({status: 'registration successful', user: user})
 }).catch(err => {
  res.send(err)
 })
})

登录的接口https://github.com/feigebaobei/nodejs/tree/master/node-session
  是否已经登录------登录------>不做事 
    |-----------没登录----->验证username/password是否正确.----正确---->设置已经登录 
                    |----------------------不正确---->返回错误

router.post('/login', (req, res, next) => {
 if (req.session.auth) { // 以req.session.auth为标记，标记是否已经通过登录验证
  res.statusCode = 200
  res.send('You are already authenticated')
 } else {
  User.findOne({username: req.body.username}).then(user => {
   if (user) {
    if (user.password !== req.body.password) {
     var err = new Error(`password error`)
     err.status = 403
     next(err)
    } else {
     req.session.auth = true // 登录成功设置标记为true
     res.statusCode = 200
     res.send('login successful')
    }
   } else { // 没用指定用户
    var err = new Error(`User ${req.body.username} does not exist!`)
    err.status = 403
    next(err)
   }
  // }).catch(err => next(err))
  }).catch(err => {
   res.send(err)
  })
 }
})

router.get('/logout', (req, res, next) => {
 if (req.session) {
  req.session.destroy() // 删除session
  res.clearCookie('session-id') // 删除cookie
  res.send('登出成功。重定向的事让前端做')
 } else {
  var err = new Error('you are not logged in!')
  err.status = 403
  next(err)
 }
})

// @/routes/news.js
var express = require('express');
var router = express.Router();
/* GET home page. */
router.get('/', function(req, res, next) {
 res.render('index', { title: 'Express' });
});
module.exports = router;

// app.js
// 1.引入路由
var index = require('./routes/index');
var users = require('./routes/users');
var news = require('./routes/news');
// 2.挂载session中间件
app.use(session({
 name: 'session-id',
 secret: '12345-67890',
 saveUninitialized: false,
 resave: false,
 store: new FileStore()
}))
// 3.挂载不需要登录验证的路由
app.use('/', index)
app.use('/users', users)
// 4.定义验证登录函数
let authFn = (req, res, next) => {
 console.log(req.session)
 if (req.session.auth) {
  next()
 } else {
  var err = new Error('You are not authenticated!')
  err.status = 403
  next(err)
 }
}
// 5.挂载需要登录验证的路由
app.use('/news', news)