详解用node.js实现简单的反向代理

const http = require('http');const url = require('url');const querystring = require('querystring');http.createServer(function(oreq, ores) {  console.log("服务已开启");  if (oreq) {    if (oreq.url !== '/favicon.ico') {      let content = '',        postData = '';      // 封装获取参数的方法      function getParmas(oUrl) {        let oQuery = (typeof oUrl === "object") ? oUrl : url.parse(oUrl, true).query,          data = {};        for (item in oQuery) {          if (item !== 'hostname') {            if (item !== 'path') {              data[item] = oQuery[item];            }          }        }        return querystring.stringify(data);      };      // 封装发起http请求的方法      function httpRequest(options, ores) {        let datas = "";        return http.request(options, function(res) {          res.setEncoding('utf8');          res.on('data', function(chunk) {            // 返回数据            datas += chunk;          });          res.on('end', function() {            ores.writeHead(200, {              "Content-Type": "application/json; charset = UTF-8",              "Access-Control-Allow-Origin": "*"            });            ores.end(datas);          })        })      };      // 数据块接收中      console.log(oreq.method.toUpperCase());      if (oreq.method.toUpperCase() === "POST") {        console.log("进入POST");        oreq.on("data", function(postDataChunk) {          postData += postDataChunk;        });        // 数据接收完毕，执行回调函数        oreq.on("end", function() {          console.log("接收完毕")          console.log(postData);            // 配置options          let oData = JSON.parse(postData);          postData = getParmas(oData);          let options = {            hostname: oData.hostname,            port: '80',            path: oData.path,            method: "POST"          };          // 发送请求          let req = httpRequest(options, ores);          req.on('error', function(e) {            console.log('problem with request: ' + e.message);          });          req.write(postData); //发送请求数据          req.end();        });      } else {        let queryObj = url.parse(oreq.url, true).query;        content = getParmas(oreq.url);        let options = {          hostname: queryObj.hostname,          port: '80',          path: queryObj.path + content,          method: "GET"        };        // 发送请求        let req = httpRequest(options, ores);        req.on('error', function(e) {          console.log('problem with request: ' + e.message);        });        req.end();      }    }  }}).listen(8080, '127.0.0.1');