[refactor] Listen for `socket` events since reverseProxy.socket is no longer set synchronously

lib/node-http-proxy/http-proxy.js

@@ -663,8 +663,8 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
   // If the reverseProxy connection has an underlying socket,
   // then execute the WebSocket handshake.
   //
-  if (typeof reverseProxy.socket !== 'undefined') {
-    reverseProxy.socket.on('data', function handshake (data) {
+  reverseProxy.once('socket', function (revSocket) {
+    revSocket.on('data', function handshake (data) {
       //
       // Ok, kind of harmfull part of code. Socket.IO sends a hash
       // at the end of handshake if protocol === 76, but we need
@@ -697,12 +697,12 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
         socket.write(sdata);
         var flushed = socket.write(data);
         if (!flushed) {
-          reverseProxy.socket.pause();
+          revSocket.pause();
           socket.once('drain', function () {
-            try { reverseProxy.socket.resume() } 
+            try { revSocket.resume() } 
             catch (er) { console.error("reverseProxy.socket.resume error: %s", er.message) }
           });
-          
+
           //
           // Force the `drain` event in 100ms if it hasn't
           // happened on its own. 
@@ -717,7 +717,7 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
         // Remove data listener on socket error because the 
         // 'handshake' has failed.
         //
-        reverseProxy.socket.removeListener('data', handshake);
+        revSocket.removeListener('data', handshake);
         return proxyError(ex);
       }
 
@@ -727,9 +727,9 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, buffer)
       //
       // Remove data listener now that the 'handshake' is complete
       //
-      reverseProxy.socket.removeListener('data', handshake);
+      revSocket.removeListener('data', handshake);
     });
-  }
+  });
 
   reverseProxy.on('error', proxyError);