目標(biāo)

• 使用express實(shí)現(xiàn)一個(gè)監(jiān)聽(tīng)3000端口的http服務(wù)如下

const express = require('express'); const app = express();app.get('/', (req, res) => {res.end('Hello Express'); }) app.get('/users',(req, res)=>{res.end(JSON.stringify({name: 'abc'})) }) app.listen(3000, ()=>{console.log('[server] server is running at http://localhost:3000 '); })

• 我們想將第一行代碼變成如下的代碼

const express = require('./lxpress.js');

• 即需要完成以下幾個(gè)操作
  1.會(huì)有一個(gè)router數(shù)組,當(dāng)使用app.get方法時(shí),會(huì)將路徑和回調(diào)函數(shù)傳入
  2.調(diào)用listen方法時(shí),會(huì)創(chuàng)建一個(gè)http服務(wù).該服務(wù)會(huì)從router數(shù)組中取出所有的路由進(jìn)行監(jiān)聽(tīng).然后根據(jù)傳入的參數(shù)進(jìn)行監(jiān)聽(tīng)

實(shí)現(xiàn)

• /lxpress.js
• 基本架構(gòu)

const http = require('http'); let routers = []; class Application{get(){},listen(){} } module.exports = () =>{return new Application(); }

• get邏輯的實(shí)現(xiàn).
  1.會(huì)接收2個(gè)參數(shù),path和handler
  2.將參數(shù)推進(jìn)routers中
  3.為了方便以后和POST方法區(qū)分,新增一個(gè)method屬性

get(path, handler){routers.push({path,method:'GET',handler}) }

• listen邏輯的實(shí)現(xiàn)
  1.在里面會(huì)創(chuàng)建一個(gè)http服務(wù),該服務(wù)接收request和response兩個(gè)參數(shù)
  2.對(duì)routers里面的每一項(xiàng)進(jìn)行解析,并為每一項(xiàng)指定路由處理函數(shù)handler
  3.接收的參數(shù)用…arguments展開(kāi)執(zhí)行

listen(){const server = http.createServer((req, res)=>{// 解構(gòu)出pathname// 使用到了url的解析需要導(dǎo)入 url --> const url = require('url');const { pathname} = url.parse(req.url, true);for(let router of routers){const {path, method, handler} = router; // 從每一項(xiàng)路由中解構(gòu)出path, method, handlerif(path === pathname && req.method === method){return handler(req, res);}}})server.listen(...arguments); }

總體代碼如下:

• /lxpress.js

const http = require('http'); const url = require('url');const router = []; class Application {get(path, handler) {router.push({path,method: 'get',handler})}listen() {const server = http.createServer((req, res) => {const { pathname } = url.parse(req.url, true);for (const item of router) {const { path, method, handler } = item;if (pathname === path && req.method.toLowerCase() === method) {return handler(req, res);}}})server.listen(...arguments);} }module.exports = () => {return new Application() }

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