[fix] Manage bookkeeping for incoming requests to the underlying sock…

…ets behind reverse proxied websocket events. Only use the appropriate variables in the closure scope of the `upgrade` event from this bookkeeping

lib/node-http-proxy.js

@@ -530,24 +530,30 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, options
     }
   }
 
-  function onUpgrade(reverseProxy) {
+  function onUpgrade(out, reverseProxy) {
+    if (!out) {
+      reverseProxy.end();
+      socket.end();
+      return;
+    }
+
     var listeners = {};
 
     // We're now connected to the server, so lets change server socket
     reverseProxy.on('data', listeners._r_data = function(data) {
       // Pass data to client
-      if (socket.writable) {
+      if (out.incoming.socket.writable) {
         try {
-          socket.write(data);
+          out.incoming.socket.write(data);
         } 
         catch (e) {
-          socket.end();
+          out.incoming.socket.end();
           reverseProxy.end();
         }
       }
     });
 
-    socket.on('data', listeners._data = function(data) {
+    out.incoming.socket.on('data', listeners._data = function(data) {
       // Pass data from client to server
       try {
         reverseProxy.write(data);
@@ -562,13 +568,13 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, options
     function detach() {
       reverseProxy.removeListener('close', listeners._r_close);
       reverseProxy.removeListener('data', listeners._r_data);
-      socket.removeListener('data', listeners._data);
-      socket.removeListener('close', listeners._close);
+      out.incoming.socket.removeListener('data', listeners._data);
+      out.incoming.socket.removeListener('close', listeners._close);
     }
 
     // Hook disconnections
     reverseProxy.on('end', listeners._r_close = function() {
-      socket.end();
+      out.incoming.socket.end();
       detach();
     });
 
@@ -592,27 +598,47 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, options
   outgoing = {
     host: options.host,
     port: options.port,
-    agent: agent,
     method: 'GET',
     path: req.url,
-    headers: req.headers
+    headers: req.headers,
   };
 
   // Make the outgoing WebSocket request
-  var request = http.request(outgoing, function () { });
-
-  // Not disconnect on update
-  agent.on('upgrade', function(request, remoteSocket, head) {
-    // Prepare socket
-    _socket(remoteSocket, true);
+  var request = agent.appendMessage(outgoing);
 
-    // Emit event
-    onUpgrade(remoteSocket);
-  });
+  //
+  // Here we set the incoming `req`, `socket` and `head` data to the outgoing
+  // request so that we can reuse this data later on in the closure scope
+  // available to the `upgrade` event. This bookkeeping is not tracked anywhere 
+  // in nodejs core and is **very** specific to proxying WebSockets.
+  //
+  request.agent = agent;
+  request.incoming = {
+    request: req,
+    socket: socket,
+    head: head
+  };
+
+  //
+  // If the agent for this particular `host` and `port` combination
+  // is not already listening for the `upgrade` event, then do so once.
+  // This will force us not to disconnect. 
+  //
+  // In addition, it's important to note the closure scope here. Since
+  // there is no mapping of the 
+  //
+  if (!agent._events || agent._events['upgrade'].length === 0) {
+    agent.on('upgrade', function (out, remoteSocket, head) {
+      // Prepare socket
+      _socket(remoteSocket, true);
+
+      // Emit event
+      onUpgrade(remoteSocket._httpMessage, remoteSocket);
+    });
+  }
 
-  var handshake;
   if (typeof request.socket !== 'undefined') {
-    request.socket.on('data', handshake = function(data) {
+    request.socket.on('data', function handshake (data) {
       // Handshaking
 
       // Ok, kind of harmfull part of code