/**
  * Returns the top level request: the HTTP request object
  *
  * @return HttpRequest
  * @api
  */
 public function getHttpRequest()
 {
     if ($this->rootRequest === null) {
         $this->rootRequest = $this->parentRequest instanceof HttpRequest ? $this->parentRequest : $this->parentRequest->getHttpRequest();
     }
     return $this->rootRequest;
 }