const koa = require('koa');

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

let server = new koa();

server.listen(,()=>{console.log('success');});

//普通路由

let router = new Router();

router.get('/a', async ctx=>{

    //ctx:上下文对象

    ctx.body='aaa';

    ctx.body+='bbb';

    console.log(ctx.body);

})

//把router怼给server才能生效

server.use(router.routes());

//1.嵌套路由:

/user

    /company

    /person

    /admin

/news

    /sport

    /woman

    /man

/car

...

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

let router = new Router();

router.get('/',async ctx=>{

    ctx.body='用户';

})

router.use('/company',require('./company'))

router.use('/admin',require('./admin'))

module.exports=router.routes();

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

let router = new Router();

router.get('/a',async ctx=>{

    ctx.body='管理员的a';

})

module.exports=router.routes();

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

let router = new Router();

router.get('/a',async ctx=>{

    ctx.body='企业的a';

});

module.exports=router.routes();

let router = new Router();

router.use('/user',require('./routers/user'));

server.use(router.routes());

//2.参数:

http://localhost:8520/news/12

http://localhost:8520/news/123/889

http://localhost:8520/news/123/555/146

quretion1: 用?id=xxx传参和/:id的区别

urlencoded      http://aaa.com/user?a=12&b=5

params          http://aaa.com/user/12/5

    urlencoded        params

    顺序灵活          顺序是死的

    可以省略          不可省略的

    不利于SEO         利于SEO(因为地址是静态的)　

const Koa = require('koa');

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

let server = new Koa();

server.listen();

let router = new Router();

router.get('/news/:id',async ctx=>{

    console.log(ctx.params);

    let {id} = ctx.params

    ctx.body=`新闻${id}`;

});

router.get('/news/:id/:id2',async ctx=>{

    console.log(ctx.params);

    let {id,id2} = ctx.params

    ctx.body=`新闻${id}_${id2}`;

});

router.get('/news/:id/:id2/:id3',async ctx=>{

    console.log(ctx.params);

    let {id,id2,id3} = ctx.params

    ctx.body=`新闻${id}_${id2}_${id3}`;

});

server.use(router.routes());

const Koa = require('koa');

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

let server = new Koa();

server.listen(,()=>{console.log('success');});

let router = new Router();

router.get('/news/',async ctx=>{

    console.log(ctx.query);

    let {id} = ctx.query;

});

server.use(router.routes());

熟悉ctx对象

server.context:相当于ctx的prototype

所以server.context适合放全局的东西

ctx.request

ctx.response

信息:

ctx.method      请求方法

ctx.url         请求地址

ctx.path        请求路径

ctx.query       get数据

ctx.ip          客户端ip

ctx.headers     请求头

比较方便的报错方法:

ctx.throw       //报错并且退出

eg:

if(!ctx.query.user || !ctx.query.pass){

    ctx.throw(,'user and password is required')

}else{

    ctx.body='成功';

}

ctx.assert()    //断言测试

ctx.assert(条件,code,msg)==if(!条件)ctx.throw

eg:

ctx.assert(ctx.query.user,,'username is required')

cnpm i koa-static -d

const static = requiere('koa-static')

新建static文件夹

static文件夹下面新建1.html

server.js加上

server.use(static('./static'));

即可

let staticRouter = new Router();

server.use(static('./static'),{

maxage:*, //缓存时间，可降低服务器压力

index: '1.html' //默认文件

})

staticRouter.all(/(\.jpg|\.png|\.gif)/i,static('./static',{

maxage:**

})) //如果是jpg,png,gif文件那就缓存两个月

staticRouter.all(/(\.css)$/i,static('./static',{

maxage:**

})); //如果是css文件那就缓存一天

staticRouter.all(/(\.html|\.htm|\.shtml)$/i,static('./static',{

maxage:**

}));

staticRouter.all('',static('./static',{

maxage:**

})); //其他文件缓存30天

server.use(staticRouter.roures());

cnpm i koa-better-body -D

ctx.request.fields

const Koa = require('koa');

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

consst body = require('koa-better-body');

let server = new Koa();

server.listen();

server.use(body({

//上传的文件储存在这里

uploadDir:'./static/upload'

}))

server.use(async ctx=>{

//文件和post数据

console.log(ctx.request.fields);

ctx.body='aaa';

});

接着form表单设置文件上传enctype='multipart/.....'

const Koa = require('koa');

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

let server = new Koa();

server.listen();

server.keys=['asdfasdf','asdfasdfa',''...]; //滚动秘钥,加密

server.use(async ctx=>{

ctx.cookies.set('user','blue',{maxAge: **,signed: true //签名});

ctx.cookies.get('user',{signed:true});

})

cnpm i koa-session -D

const Koa = require('koa');

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

const session = require('koa-session);

let server = new Koa();

server.listen();

//强制签名

server.keys=['asdfasdfas','asdfasdfasdf','sadfasdfasdf'...];

server.use(session({

maxAge:**, //有效期。20分钟，时间越长安全性越低，服务器负担越大

renew:true, //session自动续期。

},server));

server.use(async ctx=>{

if(!ctx.session['view']){

ctx.session['view']=;

}

ctx.session['view']++;

ctx.body=`欢迎您第${ctx.session.view}次来访`;

})

const Koa = require('koa');

const Router = require('koa-router);

const mysql = require('mysql');

const co = require('co-mysql');

let conn =mysql.createPool({

host:'localhost',

user:'root',

password:'',

database:'node_sql'

});

let db = co(conn);

let server = new Koa();

server.listen(;)

server.context.db=db;

server.use(async (ctx,new)=>{

try{

await next();

}catch(e){

ctx.body='错了';

}

});

server.use(async ctx=>{

let data = await ctx.db.query('SELECT * FROM user');

ctx.body=data;

});