How to create a simple http proxy in node js

Question

I m trying to create a proxy server to pass HTTP GET requests from a client to a third party website  say google   My proxy just needs to mirror incoming requests to their corresponding path on the target site  so if my client s requested url is   127 0 0 1 images srpr logo11w png   The following resource should be served   http   www google com images srpr logo11w png   Here is what I came up with   http createServer onRequest  listen 80    function onRequest  client req  client res        client req addListener  end   function             var options                 hostname   www google com               port  80              path  client req url              method  client req method             headers  client req headers                    var req http request options  function res                var body              res on  data   function  chunk                    body    chunk                              res on  end   function                       client res writeHead res statusCode  res headers                    client res end body                                       req end                It works well with html pages  but for other types of files  it just returns a blank page or some error message from target site  which varies in different sites

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Here s an implementation using node-http-proxy from nodejitsu   var http   require  http    var httpProxy   require  http-proxy    var proxy   httpProxy createProxyServer       http createServer function req  res        proxy web req  res    target   http   www google com         listen 3000

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Your code doesn t work for binary files because they can t be cast to strings in the data event handler   If you need to manipulate binary files you ll need to use a buffer   Sorry  I do not have an example of using a buffer because in my case I needed to manipulate HTML files  I just check the content type and then for text html files update them as needed   app get       function clientRequest  clientResponse      var options          hostname   google com       port  80       path  clientRequest url      method   GET            var googleRequest   http request options  function googleResponse         var body             if  String googleResponse headers  content-type    indexOf  text html       -1          googleResponse on  data   function chunk            body    chunk                    googleResponse on  end   function                Make changes to HTML files when they re done being read          body   body replace  google com gi  host         port           body   body replace              lt   body gt                 lt script src  http   localhost 3000 new-script js  type  text javascript  gt  lt  script gt  lt  body gt                       clientResponse writeHead googleResponse statusCode  googleResponse headers           clientResponse end body                           else         googleResponse pipe clientResponse            end  true                               googleRequest end

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Super simple and readable  here s how you create a local proxy server to a local HTTP server with just Node js  tested on v8 1 0   I ve found it particular useful for integration testing so here s my share          Once this is running open your browser and hit http   localhost    You ll see that the request hits the proxy and you get the HTML back       use strict    const net   require  net    const http   require  http     const PROXY PORT   80  const HTTP SERVER PORT   8080   let proxy   net createServer socket   gt        socket on  data   message   gt            console log  ---PROXY- got message   message toString              let serviceSocket   new net Socket             serviceSocket connect HTTP SERVER PORT   localhost        gt                console log  ---PROXY- Sending message to server                serviceSocket write message                        serviceSocket on  data   data   gt                console log  ---PROXY- Receiving message from server   data toString                socket write data                            let httpServer   http createServer  req  res    gt        switch  req url            case                  res writeHead 200    Content-Type    text html                 res end   lt html gt  lt body gt  lt p gt Ciao  lt  p gt  lt  body gt  lt  html gt                 break          default              res writeHead 404    Content-Type    text plain                 res end  404 Not Found               proxy listen PROXY PORT   httpServer listen HTTP SERVER PORT     https   gist github com fracasula d15ae925835c636a5672311ef584b999

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I juste wrote a proxy in nodejs that take care of HTTPS with optional decoding of the message   This proxy also can add proxy-authentification header in order to go through a corporate proxy  You need to give as argument the url to find the proxy pac file in order to configurate the usage of corporate proxy   https   github com luckyrantanplan proxy-to-proxy-https

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Here s a proxy server using request that handles redirects  Use it by hitting your proxy URL http   domain com 3000  url  your url   var http   require  http    var url   require  url    var request   require  request     http createServer onRequest  listen 3000    function onRequest req  res         var queryData   url parse req url  true  query      if  queryData url            request               url  queryData url            on  error   function e                res end e              pipe res             else           res end  no url found

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Here s a more optimized version of Mike s answer above that gets the websites Content-Type properly  supports POST and GET request  and uses your browsers User-Agent so websites can identify your proxy as a browser  You can just simply set the URL by changing url   and it will automatically set HTTP and HTTPS stuff without manually doing it  var express   require  express   var app   express   var https   require  https    var http   require  http    const   response     require  express      app use      function clientRequest  clientResponse        var url      url    https   www google com      var parsedHost   url split      splice 2  splice 0  1  join          var parsedPort      var parsedSSL      if  url startsWith  https                 parsedPort   443         parsedSSL   https       else if  url startsWith  http                 parsedPort   80         parsedSSL   http           var options            hostname  parsedHost        port  parsedPort        path  clientRequest url        method  clientRequest method        headers             User-Agent   clientRequest headers  user-agent                           var serverRequest   parsedSSL request options  function serverResponse           var body                if  String serverResponse headers  content-type    indexOf  text html       -1            serverResponse on  data   function chunk              body    chunk                          serverResponse on  end   function                  Make changes to HTML files when they re done being read            body   body replace  example    Cat                   clientResponse writeHead serverResponse statusCode  serverResponse headers             clientResponse end body                                 else           serverResponse pipe clientResponse              end  true                      clientResponse contentType serverResponse headers  content-type                               serverRequest end                  app listen 3000    console log  Running on 0 0 0 0 3000

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I don t think it s a good idea to process response received from the 3rd party server  This will only increase your proxy server s memory footprint  Further  it s the reason why your code is not working   Instead try passing the response through to the client  Consider following snippet   var http   require  http     http createServer onRequest  listen 3000    function onRequest client req  client res      console log  serve      client req url      var options         hostname   www google com       port  80      path  client req url      method  client req method      headers  client req headers         var proxy   http request options  function  res        client res writeHead res statusCode  res headers      res pipe client res          end  true                  client req pipe proxy        end  true

[javascript] How to create a simple http proxy in node.js?

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