support function for options.localAddress

Author: shasha

lib/http-proxy/common.js

@@ -60,7 +60,7 @@ common.setupOutgoing = function(outgoing, options, req, forward) {
 
 
   outgoing.agent = options.agent || false;
-  outgoing.localAddress = options.localAddress;
+  outgoing.localAddress = typeof options.localAddress === 'function' ? options.localAddress() : options.localAddress;
 
   //
   // Remark: If we are false and not upgrading, set the connection: close. This is the right thing to do