public function SurrogateKeyGenerator::onRespond in Fastly 8.3

Logs an emergency event when the X-Drupal-Cache-Tags header exceeds 16 KB.

Parameters

\Symfony\Component\HttpKernel\Event\FilterResponseEvent $event: The event to process.

File

src/EventSubscriber/SurrogateKeyGenerator.php, line 52

Class

SurrogateKeyGenerator

Generates a 'Surrogate-Key' header in the format expected by Fastly.

Namespace

Drupal\fastly\EventSubscriber

Code

public function onRespond(FilterResponseEvent $event) {
  if (!$event
    ->isMasterRequest()) {
    return;
  }
  $response = $event
    ->getResponse();
  if (method_exists($response, 'getCacheableMetadata')) {
    $surrogate_key_header_value = implode(' ', $response
      ->getCacheableMetadata()
      ->getCacheTags());
    $cache_tags = explode(' ', $surrogate_key_header_value);
    $hashes = $this->cacheTagsHash
      ->cacheTagsToHashes($cache_tags);
    $siteId = $this->cacheTagsHash
      ->getSiteId();
    $siteIdHash = $this->cacheTagsHash
      ->hashInput($siteId);
    $hashes[] = $siteIdHash;
    $surrogate_key_header_value = implode(' ', $hashes);
    $response->headers
      ->set('Surrogate-Key', $surrogate_key_header_value);
  }
}