[api] add toProxy method to allow absolute URLs to be sent when sendi…

…ng to another proxy fixes #603

lib/http-proxy.js

@@ -42,6 +42,7 @@ module.exports.createProxyServer = module.exports.createServer = function create
    *    ws     : <true/false, if you want to proxy websockets>
    *    xfwd   : <true/false, adds x-forward headers>
    *    secure : <true/false, verify SSL certificate>
+   *    toProxy: <true/false, explicitly specify if we are proxying to another proxy
    *  }
    *
    *  NOTE: `options.ws` and `options.ssl` are optional.

lib/http-proxy/common.js

@@ -44,7 +44,14 @@ common.setupOutgoing = function(outgoing, options, req, forward) {
 
 
   outgoing.agent = options.agent || false;
-  outgoing.path = url.parse(req.url).path;
+
+  //
+  // Remark: Can we somehow not use url.parse as a perf optimization?
+  //
+  outgoing.path = !options.toProxy
+    ? url.parse(req.url).path
+    : req.url;
+
   return outgoing;
 };
 
@@ -76,7 +83,7 @@ common.setupSocket = function(socket) {
 
 common.getPort = function(req) {
   var res = req.headers.host ? req.headers.host.match(/:(\d+)/) : "";
-  return res ? 
+  return res ?
     res[1] :
-    req.connection.pair ? '443' : '80' ; 
+    req.connection.pair ? '443' : '80' ;
 }