[api] Simplify the usage for the `.changeHeaders` option. Fixes #34

lib/node-http-proxy.js

@@ -235,11 +235,22 @@ var HttpProxy = exports.HttpProxy = function (options) {
   
   var self          = this;
   options           = options || {};
-  options.target    = options.target || {};
   
+  //
+  // Setup basic proxying options
+  //
   this.https        = options.https;
   this.forward      = options.forward;
-  this.target       = options.target;
+  this.target       = options.target || {};
+  
+  //
+  // Setup additional options for WebSocket proxying. When forcing 
+  // the WebSocket handshake to change the `sec-websocket-location`
+  // and `sec-websocket-origin` headers `options.source` **MUST**
+  // be provided or the operation will fail with an `origin mismatch`
+  // by definition.
+  //
+  this.source       = options.source || { host: 'localhost', port: 8000 };
   this.changeOrigin = options.changeOrigin || false;
   
   if (options.router) {
@@ -684,12 +695,18 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, options
   // Setup the incoming client socket.
   _socket(socket);
   
+  function getPort (port) {
+    port = port || 80;
+    return port - 80 === 0 ? '' : ':' + port
+  }
+  
   //
   // Get the protocol, and host for this request and create an instance
   // of `http.Agent` or `https.Agent` from the pool managed by `node-http-proxy`.
   //
   var protocolName = options.https || this.target.https ? 'https' : 'http',
-      remoteHost   = options.host + (options.port - 80 === 0 ? '' : ':' + options.port),
+      portUri      = getPort(this.source.port),
+      remoteHost   = options.host + portUri,
       agent        = _getAgent(options.host, options.port, options.https || this.target.https);
 
   // Change headers (if requested).
@@ -777,12 +794,6 @@ HttpProxy.prototype.proxyWebSocketRequest = function (req, socket, head, options
 
       // Get the Non-Printable data
       data = data.slice(Buffer.byteLength(sdata), data.length);
-
-      //
-      // Replace the host and origin headers in the Printable data
-      //
-      sdata = sdata.replace(remoteHost, options.host)
-                   .replace(remoteHost, options.host);
       
       if (self.https && !self.target.https) {
         //