const Koa = require('koa')
const bodyParser = require('koa-bodyparser')
// 路由
const router = require('./router')
const app = new Koa()

app.use(
 bodyParser({
   // 返回的对象是一个键值对，当extended为false的时候，键值对中的值就为'String'或'Array'形式，为true的时候，则可为任何数据类型。
  extended: true 
 })
)

app.use(async (ctx, next) => {
 ctx.set('Access-Control-Allow-Origin', '*')
 ctx.set('Access-Control-Allow-Headers', 'content-type')
 ctx.set(
  'Access-Control-Allow-Methods',
  'OPTIONS,GET,HEAD,PUT,POST,DELETE,PATCH'
 )
 await next()
})

// app.js

app.use(router.routes())


// router.js

const Router = require('koa-router')
let koaRequest = require('./httpRequest')
const router = new Router()

router.get('/*', async (ctx, next) => {
 const url = setQuestUrl(ctx.url)
 try {
  let res = await koaRequest(url, 'GET', ctx)
  ctx.body = res
 } catch (err) {
  ctx.body = err
 }
})

router.post('/*', async (ctx, next) => {
 const url = setQuestUrl(ctx.url)
 try {
  let res = await koaRequest(url, 'POST', ctx)
  ctx.body = res
 } catch (err) {
  ctx.body = err
 }
})

function setQuestUrl(url) {
 if (/^\/t/.test(url)) {
  return 'host1'+ url.replace(/^\/t/, '')
 }
 if (/^\/xt/.test(url)) {
  return 'host2' + url.replace(/^\/xt/, '')
 }
}

module.exports = router

const Koa = require('koa2');
const app = new Koa();

// logger
app.use(async (ctx, next) => {
 console.log('第一层洋葱 - 开始')
 await next();
 const rt = ctx.response.get('X-Response-Time');
 console.log(`${ctx.method} ${ctx.url} - ${rt}`);
 console.log('第一层洋葱 - 结束')
});

// x-response-time
app.use(async (ctx, next) => {
 console.log('第二层洋葱 - 开始')
 const start = Date.now();
 await next();
 const ms = Date.now() - start;
 ctx.set('X-Response-Time', `${ms}ms`);
 console.log('第二层洋葱 - 结束')
});

// response
app.use(async ctx => {
 console.log('第三层洋葱 - 开始')
 ctx.body = 'Hello World';
 console.log('第三层洋葱 - 结束')
});

app.listen(8000);


// 输出

第一层洋葱 - 开始
第二层洋葱 - 开始
第三层洋葱 - 开始

第三层洋葱 - 结束
第二层洋葱 - 结束
第一层洋葱 - 结束

let koa2Req = require('koa2-request')

let constConfig = require('./const')

let iToken = constConfig.iToken

let koaRequest = async function(url, method, ctx) {
 let options = {
  method: method,
  uri: url,
  timeout: 120000,
  body: ctx
   "htmlcode">

const app = require('./app')
//const createWebsocket = require('./websocket')

const server = require('http').createServer(app.callback())

server.setTimeout(2 * 60 * 1000) //设置超时时间

const { PORT = 3000 } = process.env

server.listen(PORT, () => {
 console.log(`Listening on port ${PORT}`)
})



3.5 本地开发，热重启
安装 nodemon


yarn add nodemon


设置忽略监听
nodemon.josn node项目根目录下


{
 "ignore": ["node_modules/*"] //忽略node_modules下文件修改的监听
}



package.josn
通过npm run server启动


{
 "dependencies": {
  "koa": "^2.8.1",
  "koa-bodyparser": "^4.2.1",
  "koa-router": "^7.4.0",
  "koa2-request": "^1.0.4",
  "nodemon": "^1.19.1"
 },
 "scripts": {
  "server": "nodemon index.js"
 }
}




以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。