HTTPS Proxy Server in node.js

Solutions barely exist for this, and the documentation is poor at best for supporting both on one server. The trick here is to understand that client proxy configurations may send https requests to an http proxy server. This is true for Firefox if you specify an HTTP proxy and then check “same for all protocols”.

You can handle https connections sent to an HTTP server by listening for the “connect” event. Note that you won’t have access to the response object on the connect event, only the socket and bodyhead. Data sent over this socket will remain encrypted to you as the proxy server.

In this solution, you don’t have to make your own certificates, and you won’t have certificate conflicts as a result. The traffic is simply proxied, not intercepted and rewritten with different certificates.

//  Install npm dependencies first
//  npm init
//  npm install --save [email protected]
//  npm install --save [email protected]

var httpProxy = require("http-proxy");
var http = require("http");
var url = require("url");
var net = require('net');

var server = http.createServer(function (req, res) {
  var urlObj = url.parse(req.url);
  var target = urlObj.protocol + "//" + urlObj.host;

  console.log("Proxy HTTP request for:", target);

  var proxy = httpProxy.createProxyServer({});
  proxy.on("error", function (err, req, res) {
    console.log("proxy error", err);
    res.end();
  });

  proxy.web(req, res, {target: target});
}).listen(8080);  //this is the port your clients will connect to

var regex_hostport = /^([^:]+)(:([0-9]+))?$/;

var getHostPortFromString = function (hostString, defaultPort) {
  var host = hostString;
  var port = defaultPort;

  var result = regex_hostport.exec(hostString);
  if (result != null) {
    host = result[1];
    if (result[2] != null) {
      port = result[3];
    }
  }

  return ( [host, port] );
};

server.addListener('connect', function (req, socket, bodyhead) {
  var hostPort = getHostPortFromString(req.url, 443);
  var hostDomain = hostPort[0];
  var port = parseInt(hostPort[1]);
  console.log("Proxying HTTPS request for:", hostDomain, port);

  var proxySocket = new net.Socket();
  proxySocket.connect(port, hostDomain, function () {
      proxySocket.write(bodyhead);
      socket.write("HTTP/" + req.httpVersion + " 200 Connection established\r\n\r\n");
    }
  );

  proxySocket.on('data', function (chunk) {
    socket.write(chunk);
  });

  proxySocket.on('end', function () {
    socket.end();
  });

  proxySocket.on('error', function () {
    socket.write("HTTP/" + req.httpVersion + " 500 Connection error\r\n\r\n");
    socket.end();
  });

  socket.on('data', function (chunk) {
    proxySocket.write(chunk);
  });

  socket.on('end', function () {
    proxySocket.end();
  });

  socket.on('error', function () {
    proxySocket.end();
  });

});