Symfony\Component\HttpFoundation\Response::isOk PHP Method

    public function isOk()
    {
        return 200 === $this->statusCode;
    }

 /**
  * Update a valid non cacheable Response with http cache headers
  *
  * @see http://symfony.com/fr/doc/current/book/http_cache.html
  */
 public function handleResponse(Response $response)
 {
     // do not handle invalid response
     if (!$response->isOk()) {
         return $response;
     }
     // do not handle response with http cache headers
     if ($response->isCacheable()) {
         return $response;
     }
     // seek for optional configuration
     $this->readRoutingConfiguration();
     // mark the response as private
     $response->setPrivate();
     // set the private or shared max age
     $response->setMaxAge($this->duration);
     $response->setSharedMaxAge($this->duration);
     // set expires
     $date = new \DateTime();
     $date->modify(sprintf('+%d seconds', $this->duration));
     $response->setExpires($date);
     // set a custom Cache-Control directive
     $response->headers->addCacheControlDirective('must-revalidate', true);
     return $response;
 }