Symfony\Component\HttpKernel\Event\GetResponseEvent::hasResponse PHP Method

    public function hasResponse()
    {
        return null !== $this->response;
    }

 public function onKernelRequest(GetResponseEvent $event)
 {
     $this->logger->debug('Entity builder listener: catch kernel.request event');
     // If this is not a master request, skip handling
     if (!$event->isMasterRequest()) {
         $this->logger->debug('Entity builder listener: this is not master request, skip');
         return;
     }
     // If content already prepared
     if ($event->hasResponse()) {
         $this->logger->debug('Entity builder listener: event already has response, skip');
         return;
     }
     // Getting request
     $request = $event->getRequest();
     // Getting action
     $apiServerAction = $event->getRequest()->attributes->get('apiAction');
     /* @var $apiServerAction ApiServerAction */
     // Something wrong
     if (!$apiServerAction) {
         $this->logger->error('Request parser listener: request has no apiAction attribute, throwing access denied exception');
         throw new AccessDeniedHttpException();
     }
     // Creating request data entity
     try {
         $apiEntity = $apiServerAction->getRequestedEntity($request->attributes->get('apiData'));
     } catch (\Exception $e) {
         $this->logger->notice(sprintf('Request parser listener: unable to convert apiData to entity ("%s"), apiEntity set tu null', $e->getMessage()));
         $apiEntity = null;
     }
     // Setting request attributes
     $request->attributes->set('requestData', $apiEntity);
     // Cleaning request attributes
     $request->attributes->remove('apiData');
 }