/**
* Transforms a HtmlResponse to a BigPipeResponse.
*
* @param \Symfony\Component\HttpKernel\Event\FilterResponseEvent $event
* The event to process.
*/
public function onRespond(FilterResponseEvent $event)
{
$response = $event->getResponse();
if (!$response instanceof HtmlResponse) {
return;
}
$attachments = $response->getAttachments();
// If there are no no-JS BigPipe placeholders, unwrap the scripts_bottom
// markup.
// @see onRespondEarly()
// @see \Drupal\big_pipe\Render\BigPipe::sendPreBody()
if (empty($attachments['big_pipe_nojs_placeholders'])) {
$content = $response->getContent();
$content = str_replace('<drupal-big-pipe-scripts-bottom-marker>', '', $content);
$response->setContent($content);
}
// If there are neither BigPipe placeholders nor no-JS BigPipe placeholders,
// there isn't anything dynamic in this response, and we can return early:
// there is no point in sending this response using BigPipe.
if (empty($attachments['big_pipe_placeholders']) && empty($attachments['big_pipe_nojs_placeholders'])) {
return;
}
$big_pipe_response = new BigPipeResponse();
$big_pipe_response->setBigPipeService($this->bigPipe);
// Clone the HtmlResponse's data into the new BigPipeResponse.
$big_pipe_response->headers = clone $response->headers;
$big_pipe_response->setStatusCode($response->getStatusCode())->setContent($response->getContent())->setAttachments($attachments)->addCacheableDependency($response->getCacheableMetadata());
// A BigPipe response can never be cached, because it is intended for a
// single user.
// @see http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.9.1
$big_pipe_response->setPrivate();
// Inform surrogates how they should handle BigPipe responses:
// - "no-store" specifies that the response should not be stored in cache;
// it is only to be used for the original request
// - "content" identifies what processing surrogates should perform on the
// response before forwarding it. We send, "BigPipe/1.0", which surrogates
// should not process at all, and in fact, they should not even buffer it
// at all.
// @see http://www.w3.org/TR/edge-arch/
$big_pipe_response->headers->set('Surrogate-Control', 'no-store, content="BigPipe/1.0"');
// Add header to support streaming on NGINX + php-fpm (nginx >= 1.5.6).
$big_pipe_response->headers->set('X-Accel-Buffering', 'no');
$event->setResponse($big_pipe_response);
}
