[api minor] Small refactor to emit `webSocketProxyError` from a single helper...

[api minor] Small refactor to emit `webSocketProxyError` from a single helper function on any of the various `error` events in the proxy chain

lib/node-http-proxy.js

@@ -640,6 +640,15 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, options
   // Make the outgoing WebSocket request
   var reverseProxy = agent.appendMessage(outgoing);
 
+  function proxyError (err) {
+    reverseProxy.end();
+    if (self.emit('webSocketProxyError', req, socket, head)) {
+      return;
+    }
+    
+    socket.end();
+  }
+
   //
   // 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
@@ -665,7 +674,8 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, options
     agent.on('upgrade', function (_, remoteSocket, head) {
       //
       // Prepare the socket for the reverseProxy request and begin to 
-      // stream data between the two sockets
+      // stream data between the two sockets. Here it is important to 
+      // note that `remoteSocket._httpMessage === reverseProxy`.
       //
       _socket(remoteSocket, true);
       onUpgrade(remoteSocket._httpMessage, remoteSocket);
@@ -705,26 +715,19 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, options
         socket.write(sdata);
         socket.write(data);
       } 
-      catch (e) {
-        reverseProxy.end();
-        socket.end();
+      catch (ex) {
+        proxyError(ex)
       }
 
       // Catch socket errors
-      socket.on('error', function() {
-        reverseProxy.end();
-        socket.end();
-      });
+      socket.on('error', proxyError);
 
       // Remove data listener now that the 'handshake' is complete
       reverseProxy.socket.removeListener('data', handshake);
     });
   }
   
-  reverseProxy.on('error', function (err) {
-    reverseProxy.end();
-    socket.end();
-  });
+  reverseProxy.on('error', proxyError);
 
   try {
     //
@@ -733,8 +736,7 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, options
     reverseProxy.write(head);
   } 
   catch (ex) {
-    reverseProxy.end();
-    socket.end();
+    proxyError(ex);
   }
   
   //