1- login登录功能的实现

login.js

const Router = require("koa-router");
const router = new Router();
router.get("/login",async ctx=>{
    if(ctx.cookies.get('login')){
        await ctx.redirect('/m1')
    }else{
        await ctx.render("login")
    }
})
module.exports = router;

login.html

<form action="/m1/doLogin" method="POST" role="form">
  <legend>登录</legend>
  <div class="form-group">
    <label for="">用户名</label>
  <input type="text" class="form-control" name="username" id="" placeholder="请输入用户名">
    </div>
  <div class="form-group">
    <label for="">密码</label>
  <input type="text" class="form-control" name="pwd" id="" placeholder="请输入密码">
    </div>
  <button type="submit" class="btn btn-primary">登录</button>
</form>

doLogin.js

POST /m1/doLogin
// 查询数据库
router.post("/m1/doLogin",async ctx=>{
    /* username,pwd */
    var {username,pwd} = ctx.request.body;
    var res = await UserModel.find({username:username,pwd:Number(pwd)});
    console.log(res)
    /* 根据res的长度判断用户名和密码是否正确 */
    if(res.length){
        ctx.cookies.set("login",true)
        ctx.redirect("/m1")
    }else{
        ctx.body = "<script>alert('用户名或密码错误');location.href='/login'</script>"
    }
})

2- 使用cookies实现登录拦截

index.js

app.use(async (ctx,next)=>{
    var url = ctx.request.url;
    console.log(url)
    if(url =="/login"  || url =="/m1/doLogin"){
        await next();
    }else{
        if(ctx.cookies.get("login")){
            await next()
        }else{
            ctx.redirect("/login")
        }
    }
})

3- 退出登录

router.get("/m1/logout",async ctx=>{
   ctx.cookies.set("login",null);
   ctx.redirect("/login")
})

4- 注册

const Router = require("koa-router");
const router = new Router();
const UserModel = require('../../models/User')
router.post("/m1/doRegister",async ctx=>{
    var {username,pwd} = ctx.request.body
    var data = new UserModel({username,pwd:Number(pwd)})
    var res = await UserModel.find({username})
    if(res.length){
        ctx.body="<script>alert('用户名已存在'); location.href='/register'</script>"
    }else{
        data.save(err=>{
            if(err) {throw err}
        })
        ctx.cookies.set("login",true)
        ctx.redirect('/m1')
    }
})
module.exports = router;