how to make a proxy server node.js

                                    var fs = require('fs');

var http = require('http'),

var https = require('https'),

var httpProxy = require('http-proxy');

isHttps = true;

var options = {

  ssl: {

    key: fs.readFileSync('valid-key.pem'),

    cert: fs.readFileSync('valid-cert.pem')

  }

};

proxyServer = proxy.createProxyServer({target:'http://127.0.0.1:9000'});

proxyServer.listen(8000);

if (isHttps){

   server = https.createServer(options.ssl, function(req, res) {

     console.log(“https request”);

     proxyServer.web(req, res, { target: req.url });

     proxyServer.on('error', function(e) {

  console.log("Error in proxy call");

     });

     proxyServer.listen(443);

   });

}else{

  server = http.createServer(function (req, res) {

  console.log(req.url);

  proxyServer.web(req, res, { target: req.url });

  proxyServer.on('error', function(e) {

   console.log("Error in proxy call");

  });

    });

 }

 server.listen(9000);