class DefaultExceptionHtmlSubscriber in Zircon Profile 8

Exception subscriber for handling core default HTML error pages.

Hierarchy

• class \Drupal\Core\EventSubscriber\HttpExceptionSubscriberBase implements EventSubscriberInterface
  • class \Drupal\Core\EventSubscriber\DefaultExceptionHtmlSubscriber

1 string reference to 'DefaultExceptionHtmlSubscriber'

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

core/core.services.yml

1 service uses DefaultExceptionHtmlSubscriber

exception.default_html in core/core.services.yml

Drupal\Core\EventSubscriber\DefaultExceptionHtmlSubscriber

File

core/lib/Drupal/Core/EventSubscriber/DefaultExceptionHtmlSubscriber.php, line 24

Contains \Drupal\Core\EventSubscriber\DefaultExceptionHtmlSubscriber.

Namespace

Drupal\Core\EventSubscriber

class DefaultExceptionHtmlSubscriber extends HttpExceptionSubscriberBase {

  /**
   * The HTTP kernel.
   *
   * @var \Symfony\Component\HttpKernel\HttpKernelInterface
   */
  protected $httpKernel;

  /**
   * The logger instance.
   *
   * @var \Psr\Log\LoggerInterface
   */
  protected $logger;

  /**
   * The redirect destination service.
   *
   * @var \Drupal\Core\Routing\RedirectDestinationInterface
   */
  protected $redirectDestination;

  /**
   * Constructs a new DefaultExceptionHtmlSubscriber.
   *
   * @param \Symfony\Component\HttpKernel\HttpKernelInterface $http_kernel
   *   The HTTP kernel.
   * @param \Psr\Log\LoggerInterface $logger
   *   The logger service.
   * @param \Drupal\Core\Routing\RedirectDestinationInterface $redirect_destination
   *   The redirect destination service.
   */
  public function __construct(HttpKernelInterface $http_kernel, LoggerInterface $logger, RedirectDestinationInterface $redirect_destination) {
    $this->httpKernel = $http_kernel;
    $this->logger = $logger;
    $this->redirectDestination = $redirect_destination;
  }

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

    // A very low priority so that custom handlers are almost certain to fire
    // before it, even if someone forgets to set a priority.
    return -128;
  }

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

  /**
   * Handles a 401 error for HTML.
   *
   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
   *   The event to process.
   */
  public function on401(GetResponseForExceptionEvent $event) {
    $this
      ->makeSubrequest($event, Url::fromRoute('system.401')
      ->toString(), Response::HTTP_UNAUTHORIZED);
  }

  /**
   * Handles a 403 error for HTML.
   *
   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
   *   The event to process.
   */
  public function on403(GetResponseForExceptionEvent $event) {
    $this
      ->makeSubrequest($event, Url::fromRoute('system.403')
      ->toString(), Response::HTTP_FORBIDDEN);
  }

  /**
   * Handles a 404 error for HTML.
   *
   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
   *   The event to process.
   */
  public function on404(GetResponseForExceptionEvent $event) {
    $this
      ->makeSubrequest($event, Url::fromRoute('system.404')
      ->toString(), Response::HTTP_NOT_FOUND);
  }

  /**
   * Makes a subrequest to retrieve the default error page.
   *
   * @param \Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent $event
   *   The event to process
   * @param string $url
   *   The path/url to which to make a subrequest for this error message.
   * @param int $status_code
   *   The status code for the error being handled.
   */
  protected function makeSubrequest(GetResponseForExceptionEvent $event, $url, $status_code) {
    $request = $event
      ->getRequest();
    $exception = $event
      ->getException();
    if (!($url && $url[0] == '/')) {
      $url = $request
        ->getBasePath() . '/' . $url;
    }
    $current_url = $request
      ->getBasePath() . $request
      ->getPathInfo();
    if ($url != $request
      ->getBasePath() . '/' && $url != $current_url) {
      if ($request
        ->getMethod() === 'POST') {
        $sub_request = Request::create($url, 'POST', $this->redirectDestination
          ->getAsArray() + [
          '_exception_statuscode' => $status_code,
        ] + $request->request
          ->all(), $request->cookies
          ->all(), [], $request->server
          ->all());
      }
      else {
        $sub_request = Request::create($url, 'GET', $request->query
          ->all() + $this->redirectDestination
          ->getAsArray() + [
          '_exception_statuscode' => $status_code,
        ], $request->cookies
          ->all(), [], $request->server
          ->all());
      }
      try {

        // Persist the 'exception' attribute to the subrequest.
        $sub_request->attributes
          ->set('exception', $request->attributes
          ->get('exception'));

        // Persist the access result attribute to the subrequest, so that the
        // error page inherits the access result of the master request.
        $sub_request->attributes
          ->set(AccessAwareRouterInterface::ACCESS_RESULT, $request->attributes
          ->get(AccessAwareRouterInterface::ACCESS_RESULT));

        // Carry over the session to the subrequest.
        if ($session = $request
          ->getSession()) {
          $sub_request
            ->setSession($session);
        }
        $response = $this->httpKernel
          ->handle($sub_request, HttpKernelInterface::SUB_REQUEST);

        // Only 2xx responses should have their status code overridden; any
        // other status code should be passed on: redirects (3xx), error (5xx)…
        // @see https://www.drupal.org/node/2603788#comment-10504916
        if ($response
          ->isSuccessful()) {
          $response
            ->setStatusCode($status_code);
        }

        // Persist any special HTTP headers that were set on the exception.
        if ($exception instanceof HttpExceptionInterface) {
          $response->headers
            ->add($exception
            ->getHeaders());
        }
        $event
          ->setResponse($response);
      } catch (\Exception $e) {

        // If an error happened in the subrequest we can't do much else. Instead,
        // just log it. The DefaultExceptionSubscriber will catch the original
        // exception and handle it normally.
        $error = Error::decodeException($e);
        $this->logger
          ->log($error['severity_level'], '%type: @message in %function (line %line of %file).', $error);
      }
    }
  }

}

Members

Name	Modifiers	Type	Description	Overrides
DefaultExceptionHtmlSubscriber::$httpKernel	protected	property	The HTTP kernel.
DefaultExceptionHtmlSubscriber::$logger	protected	property	The logger instance.
DefaultExceptionHtmlSubscriber::$redirectDestination	protected	property	The redirect destination service.
DefaultExceptionHtmlSubscriber::getHandledFormats	protected	function	Specifies the request formats this subscriber will respond to. Overrides HttpExceptionSubscriberBase::getHandledFormats
DefaultExceptionHtmlSubscriber::getPriority	protected static	function	Specifies the priority of all listeners in this class. Overrides HttpExceptionSubscriberBase::getPriority	1
DefaultExceptionHtmlSubscriber::makeSubrequest	protected	function	Makes a subrequest to retrieve the default error page.
DefaultExceptionHtmlSubscriber::on401	public	function	Handles a 401 error for HTML.
DefaultExceptionHtmlSubscriber::on403	public	function	Handles a 403 error for HTML.	1
DefaultExceptionHtmlSubscriber::on404	public	function	Handles a 404 error for HTML.	1
DefaultExceptionHtmlSubscriber::__construct	public	function	Constructs a new DefaultExceptionHtmlSubscriber.	1
HttpExceptionSubscriberBase::getSubscribedEvents	public static	function	Registers the methods in this class that should be listeners. Overrides EventSubscriberInterface::getSubscribedEvents
HttpExceptionSubscriberBase::onException	public	function	Handles errors for this subscriber.