class Fast404ExceptionHtmlSubscriber in Drupal 10

High-performance 404 exception subscriber.

This subscriber will return a minimalist 404 response for HTML requests without running a full page theming operation.

Fast 404s are configured using the system.performance configuration object. There are the following options:

• system.performance:fast_404.exclude_paths: A regular expression to match paths to exclude, such as images generated by image styles, or dynamically-resized images. The default pattern provided below also excludes the private file system. If you need to add more paths, you can add '|path' to the expression.
• system.performance:fast_404.paths: A regular expression to match paths that should return a simple 404 page, rather than the fully themed 404 page. If you don't have any aliases ending in htm or html you can add '|s?html?' to the expression.
• system.performance:fast_404.html: The html to return for simple 404 pages.

Hierarchy

• class \Drupal\Core\EventSubscriber\Fast404ExceptionHtmlSubscriber extends \Drupal\Core\EventSubscriber\HttpExceptionSubscriberBase

1 string reference to 'Fast404ExceptionHtmlSubscriber'

core.services.yml in core/core.services.yml

core/core.services.yml

1 service uses Fast404ExceptionHtmlSubscriber

exception.fast_404_html in core/core.services.yml

Drupal\Core\EventSubscriber\Fast404ExceptionHtmlSubscriber

File

core/lib/Drupal/Core/EventSubscriber/Fast404ExceptionHtmlSubscriber.php, line 33

Namespace

Drupal\Core\EventSubscriber

class Fast404ExceptionHtmlSubscriber extends HttpExceptionSubscriberBase {

  /**
   * The config factory.
   *
   * @var \Drupal\Core\Config\ConfigFactoryInterface
   */
  protected $configFactory;

  /**
   * The cache tags invalidator.
   *
   * @var \Drupal\Core\Cache\CacheTagsInvalidatorInterface
   */
  protected $cacheTagsInvalidator;

  /**
   * Constructs a new Fast404ExceptionHtmlSubscriber.
   *
   * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
   *   The configuration factory.
   * @param \Drupal\Core\Cache\CacheTagsInvalidatorInterface $cache_tags_invalidator
   *   The cache tags invalidator.
   */
  public function __construct(ConfigFactoryInterface $config_factory, CacheTagsInvalidatorInterface $cache_tags_invalidator) {
    $this->configFactory = $config_factory;
    $this->cacheTagsInvalidator = $cache_tags_invalidator;
  }

  /**
   * {@inheritdoc}
   */
  protected static function getPriority() {

    // A very high priority so that it can take precedent over anything else,
    // and thus be fast.
    return 200;
  }

  /**
   * {@inheritdoc}
   */
  protected function getHandledFormats() {
    return [
      'html',
    ];
  }

  /**
   * Handles a 404 error for HTML.
   *
   * @param \Symfony\Component\HttpKernel\Event\ExceptionEvent $event
   *   The event to process.
   */
  public function on404(ExceptionEvent $event) {
    $request = $event
      ->getRequest();
    $config = $this->configFactory
      ->get('system.performance');
    $exclude_paths = $config
      ->get('fast_404.exclude_paths');
    if ($config
      ->get('fast_404.enabled') && $exclude_paths && !preg_match($exclude_paths, $request
      ->getPathInfo())) {
      $fast_paths = $config
        ->get('fast_404.paths');
      if ($fast_paths && preg_match($fast_paths, $request
        ->getPathInfo())) {
        $fast_404_html = strtr($config
          ->get('fast_404.html'), [
          '@path' => Html::escape($request
            ->getUri()),
        ]);
        $response = new HtmlResponse($fast_404_html, Response::HTTP_NOT_FOUND);
        $event
          ->setResponse($response);
      }
    }
  }

  /**
   * Invalidates 4xx-response cache tag if fast 404 config is changed.
   *
   * @param \Drupal\Core\Config\ConfigCrudEvent $event
   *   The configuration event.
   */
  public function onConfigSave(ConfigCrudEvent $event) : void {
    $saved_config = $event
      ->getConfig();
    if ($saved_config
      ->getName() === 'system.performance' && $event
      ->isChanged('fast_404')) {
      $this->cacheTagsInvalidator
        ->invalidateTags([
        '4xx-response',
      ]);
    }
  }

  /**
   * {@inheritdoc}
   */
  public static function getSubscribedEvents() : array {
    $events = parent::getSubscribedEvents();
    $events[ConfigEvents::SAVE] = 'onConfigSave';
    return $events;
  }

}