function FormAjaxSubscriber::onException

Catches a form AJAX exception and build a response from it.

Parameters

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

File

core/lib/Drupal/Core/Form/EventSubscriber/FormAjaxSubscriber.php, line 82

Class

FormAjaxSubscriber

Wraps AJAX form submissions that are triggered via an exception.

Namespace

Code

public function onException(ExceptionEvent $event) {
    $exception = $event->getThrowable();
    $request = $event->getRequest();
    // Render a nice error message in case we have a file upload which exceeds
    // the configured upload limit.
    if ($exception instanceof BrokenPostRequestException && $request->query
        ->has(FormBuilderInterface::AJAX_FORM_REQUEST)) {
        $this->messenger
            ->addError($this->t('An unrecoverable error occurred. The uploaded file likely exceeded the maximum file size (@size) that this server supports.', [
            '@size' => $this->formatSize($exception->getSize()),
        ]));
        $response = new AjaxResponse(NULL, 200);
        $status_messages = [
            '#type' => 'status_messages',
        ];
        $response->addCommand(new PrependCommand(NULL, $status_messages));
        $event->allowCustomResponseCode();
        $event->setResponse($response);
        return;
    }
    // Extract the form AJAX exception (it may have been passed to another
    // exception before reaching here).
    if ($exception = $this->getFormAjaxException($exception)) {
        $request = $event->getRequest();
        $form = $exception->getForm();
        $form_state = $exception->getFormState();
        // Set the build ID from the request as the old build ID on the form.
        $form['#build_id_old'] = $request->request
            ->get('form_build_id');
        try {
            $response = $this->formAjaxResponseBuilder
                ->buildResponse($request, $form, $form_state, []);
            // Since this response is being set in place of an exception, explicitly
            // mark this as a 200 status.
            $response->setStatusCode(200);
            $event->allowCustomResponseCode();
            $event->setResponse($response);
        } catch (\Exception $e) {
            // Otherwise, replace the existing exception with the new one.
            $event->setThrowable($e);
        }
    }
}