nodeJS搭建一个简单的(代理)web服务器

前端获取数据时经常遇见跨域问题，以前一直用nginx做反向代理。最近在用vuejs，发现webpack-dev-server的代理简单好用。于是仿照写了一个简单的web服务器，用于非webpack的项目。

 const request = require('request');
 const express = require('express');
 const path = require('path');

 const app = express();

 const proxyTable = {
   '/wcf': {
     target: 'http://localhost/wcf'
   }
 };

 app.use(function(req, res,next) {
   const url = req.url;
   if (req.method == 'OPTIONS') {
       console.log('options_url: ', url);

       // res.header("Access-Control-Allow-Origin", req.headers.origin || '*');
       // res.header("Access-Control-Allow-Headers", "Content-Type, Authorization, X-Requested-With");
       // res.header("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");

       // res.header("Access-Control-Allow-Credentials", true);

       res.status(200).send('OK');
       return;
   } 

   // console.log('req_url: ', url);
   next();
 });

 app.use(express.static(path.join(__dirname, 'static')));

 app.use('/', function(req, res) {
   const url = req.url;
   const proxy = Object.keys(proxyTable);
   let not_found = true;
   for (let index = 0; index < proxy.length; index++) {
     const k = proxy[index];
     const i = url.indexOf(k);
     if (i >= 0) {
       not_found = false;
       const element = proxyTable[k];
       const newUrl = element.target + url.slice(i+k.length);
       req.pipe(request({url: newUrl, timeout: 60000},(err)=>{
         if(err){
           console.log('error_url: ', err.code,url);
           res.status(500).send('');
         }
       })).pipe(res);
       break;
     }
   }
   if(not_found) {
     console.log('not_found_url: ', url);
     res.status(404).send('Not found');
   } else {
     console.log('proxy_url: ', url);
   }
 });

 const PORT = 8080;
 app.listen(PORT, () => {
   console.log('HTTP Server is running on: http://localhost:%s', PORT);
 });