public function CacheableResponseSubscriber::onRespond in Pantheon Advanced Page Cache 8

Same name in this branch

1. 8 src/EventSubscriber/CacheableResponseSubscriber.php \Drupal\pantheon_advanced_page_cache\EventSubscriber\CacheableResponseSubscriber::onRespond()
2. 8 tests/modules/pantheon_advanced_page_cache_test/src/EventSubscriber/CacheableResponseSubscriber.php \Drupal\pantheon_advanced_page_cache_test\EventSubscriber\CacheableResponseSubscriber::onRespond()

Adds Surrogate-Key header to cacheable master responses.

Parameters

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

File

src/EventSubscriber/CacheableResponseSubscriber.php, line 71

Class

CacheableResponseSubscriber

Adds Surrogate-Key header to cacheable master responses.

Namespace

Drupal\pantheon_advanced_page_cache\EventSubscriber

Code

public function onRespond(FilterResponseEvent $event) {
  if (!$event
    ->isMasterRequest()) {
    return;
  }
  $response = $event
    ->getResponse();
  if ($response instanceof CacheableResponseInterface) {
    $tags = $response
      ->getCacheableMetadata()
      ->getCacheTags();

    // Rename all _list cache tags to _emit_list to avoid clearing list cache
    // tags by default.
    if ($this
      ->getOverrideListTagsSetting()) {
      foreach ($tags as $key => $tag) {
        $tags[$key] = str_replace('_list', '_emit_list', $tag);
      }
    }
    $tags_string = implode(' ', $tags);
    if (25000 < strlen($tags_string)) {
      $tags_string = substr($tags_string, 0, 25000);

      // The string might have cut of in the middle of a tag.
      // So now find the the last occurence of a space and cut to that length.
      $tags_string = substr($tags_string, 0, strrpos($tags_string, ' '));
      $this->logger
        ->log(RfcLogLevel::WARNING, 'More cache tags were present than could be passed in the Surrogate-Key HTTP Header due to length constraints. To avoid a 502 error the list of surrogate keys was trimmed to a maximum length of 25,000 bytes. Since keys beyond the 25,000 maximum were removed this page will not be cleared from the cache when any of the removed keys are cleared (usually by entity save operations) as they have been stripped from the surrogate key header. See https://www.drupal.org/project/pantheon_advanced_page_cache/issues/2973861 for more information about how you can filter out redundant or unnecessary cache metadata.');
    }
    $response->headers
      ->set('Surrogate-Key', $tags_string);
  }
}