cancel_button.module in Entity Form Cancel Button 8

Contains implementations of hooks.

File

cancel_button.module

<?php

/**
 * @file
 * Contains implementations of hooks.
 */
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Url;
use Drupal\Component\Utility\UrlHelper;
use Drupal\Core\Entity\EntityFormInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\field_ui\FieldUI;
use Drupal\core\Entity\EntityInterface;

/**
 * Implements hook_form_alter().
 *
 * Add a 'Cancel' button to all entity forms.
 */
function cancel_button_form_alter(&$form, FormStateInterface $form_state) {
  if ($form_state
    ->getFormObject() instanceof EntityFormInterface) {

    // If this is an entity form, get the current request and the current route.
    // The current request exposes the 'destination' parameter and the HTTP
    // Referer, and current route match exposes the route for this form
    // (to differentiate if this is a entity add or entity edit form.
    $current_request = \Drupal::requestStack()
      ->getCurrentRequest();
    $current_route_match = \Drupal::service('current_route_match');
    $route_provider = \Drupal::service('router.route_provider');
    $destination = NULL;

    // Get the entity type corresponding to the entity form.
    $entity_type_id = $form_state
      ->getFormObject()
      ->getEntity()
      ->getEntityTypeId();
    $cancel_button_settings = \Drupal::config('cancel_button.settings')
      ->get('entity_type_cancel_destination');
    $entity_type = \Drupal::entityTypeManager()
      ->getDefinition($entity_type_id);

    // Cancel button is enabled/disabled at the entity type level, determine
    // if the button has to be enabled.
    if (array_key_exists($entity_type_id, $cancel_button_settings)) {
      $cancel_button_setting_enabled = $cancel_button_settings[$entity_type_id]['enabled'];
    }
    else {
      $cancel_button_setting_enabled = $cancel_button_settings['default']['enabled'];
    }
    if ($cancel_button_setting_enabled) {

      // If the 'cancel' button is enabled for this entity type,
      // get the default redirect for the current entity type as a
      // final fallback. If this is a bundle, then the redirect path is
      // stored at the bundle level.
      if ($entity_type
        ->hasKey('bundle')) {
        $entity = $form_state
          ->getFormObject()
          ->getEntity();
        $bundle_entity_id = $entity
          ->bundle();
        $config_key = $entity_type_id . '_' . $bundle_entity_id;
      }
      else {
        $config_key = $entity_type_id;
      }
      if (array_key_exists($config_key, $cancel_button_settings)) {
        $cancel_button_path = $cancel_button_settings[$config_key]['path'];
      }
      else {
        $cancel_button_path = $cancel_button_settings['default']['path'];
      }

      // If there is a form redirect set, use that for the cancel button.
      if ($redirect = $form_state
        ->getRedirect()) {

        // Set the destination from the form state redirect.
        $destination = Url::fromRoute($redirect
          ->getRouteName());
      }
      elseif ($destination_param = $current_request->query
        ->get('destination')) {

        // The contextual links menu does not correctly prefix the destination
        // parameter with a leading slash, so we need to add it if it's missing.
        if (strpos($destination_param, '/') !== 0) {
          $destination_param = '/' . $destination_param;
        }
        $destination = Url::fromUserInput($destination_param);
      }
      elseif (preg_match('/entity\\..+\\.*edit_form/', $current_route_match
        ->getRouteName())) {

        // If this is the entity edit form (as opposed to the entity add form),
        // set the destination as the canonical route if available and the
        // collection route otherwise.
        // For field configs, the fields list for the bundle should be
        // displayed.
        $parameter_bag = $current_route_match
          ->getParameters();
        if ($parameter_bag) {
          $parameters = $parameter_bag
            ->all();
          if ($parameters && array_key_exists($entity_type_id, $parameters)) {
            if ($parameters[$entity_type_id] instanceof EntityInterface) {
              $id = $parameters[$entity_type_id]
                ->id();
              $entity = \Drupal::entityTypeManager()
                ->getStorage($entity_type_id)
                ->load($id);
              if ($entity
                ->hasLinkTemplate('canonical')) {
                $canonical_destination = $entity
                  ->toUrl('canonical');
                $canonical_route_name = $canonical_destination
                  ->getRouteName();
                if (!empty($route_provider
                  ->getRoutesByNames([
                  $canonical_route_name,
                ]))) {
                  $destination = $canonical_destination;
                }
              }

              // Redirect to the collection otherwise.
              if (empty($destination) && $entity
                ->hasLinkTemplate('collection')) {
                $collection_destination = $entity
                  ->toUrl('collection');
                $collection_route_name = $collection_destination
                  ->getRouteName();
                if (!empty($route_provider
                  ->getRoutesByNames([
                  $collection_route_name,
                ]))) {
                  $destination = $collection_destination;
                }
              }

              // For field configs, redirect to the overview form.
              if ($entity_type_id == 'field_config') {
                $destination = FieldUI::getOverviewRouteInfo($entity
                  ->getTargetEntityTypeId(), $entity
                  ->getTargetBundle());
              }
            }
          }
        }
      }
      else {
        $http_referer = $current_request->headers
          ->get('referer');
        if (!empty($http_referer) && $http_referer !== $current_request
          ->getUri()) {

          // If the HTTP Referer is NOT the current page (e.g., not from a page
          // reload), set the destination from the referer.
          $redirect = UrlHelper::stripDangerousProtocols($http_referer);
          $destination = Url::fromUri($redirect);
        }
      }
      if (empty($destination)) {
        $destination = Url::fromUserInput($cancel_button_path);
      }

      // Allow other modules to alter the destination.
      $alter_context = [
        'settings' => $cancel_button_settings,
        'request' => $current_request,
        'route_match' => $current_route_match,
        'entity_type' => $entity_type,
        'form_state' => $form_state,
      ];
      \Drupal::moduleHandler()
        ->alter('cancel_button_destination', $destination, $alter_context);
      if (!is_null($destination) && !isset($form['actions']['cancel'])) {
        $form['actions']['cancel'] = [
          '#type' => 'link',
          '#title' => t('Cancel'),
          '#url' => $destination,
          '#attributes' => [
            'class' => [
              'button',
            ],
          ],
          '#weight' => 30,
        ];
      }
    }
  }
}

/**
 * {@inheritdoc}
 */
function cancel_button_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'cancel_button.admin_settings':
      return t('<p>Enter the default paths to use for the <strong>Cancel</strong> button on entity forms when there is no form state redirect, destination query parameter, or HTTP Referer.</p>');
  }
}

Functions

Name	Description
cancel_button_form_alter	Implements hook_form_alter().
cancel_button_help