public function doExecute(APIRequest $request)
 {
     $action = $request->getAction();
     if (!is_callable(array($this, $action))) {
         throw new RESTCommandException('Resource "' . $request->getResource() . '" does not support action "' . $action . '"');
     }
     return call_user_func(array($this, $action), $request);
 }