alert_banner.module

<?php

/**
 * @file
 * Alert module.
 */

use Drupal\Core\Entity\EntityTypeInterface;
use Drupal\Core\Routing\RouteMatchInterface;

/**
 * Implements hook_help().
 */
function alert_banner_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the alert_banner module.
    case 'help.page.alert_banner':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Provides ability to display site-wide alert messages and announcements at the top of all pages.') . '</p>';
      return $output;
  }
}

/**
 * Implements hook_entity_bundle_field_info_alter().
 */
function alert_banner_entity_bundle_field_info_alter(&$fields, EntityTypeInterface $entity_type, $bundle) {
  if ($entity_type->id() == 'node' && $bundle == 'alert_banner') {
    if (isset($fields['field_alert_message'])) {
      $fields['field_alert_message']->addConstraint('HtmlNotEmpty', []);
    }
  }
}

/**
 * Implements hook_page_top().
 */
function alert_banner_page_top(array &$page_top) {
  $settings = \Drupal::config('alert_banner.settings');
  if (!$settings->get('enable')) {
    return;
  }

  // Do not show alerts on admin pages.
  if (\Drupal::service('router.admin_context')->isAdminRoute() &&
    !$settings->get('show_on_admin')) {
    return;
  }

  $entity_type_manager = \Drupal::entityTypeManager();

  // Retrieve the endpoint of Alert banners Rest.
  $endpoint = '/alert-banners?_format=json';
  try {
    /** @var \Drupal\views\Entity\View $alert_view */
    $alert_view = $entity_type_manager->getStorage('view')
      ->load('alert_banners');
    if ($alert_view) {
      $display = $alert_view->getDisplay('rest_export_alerts');
      if (!empty($display['display_options']['path'])) {
        $endpoint = '/' . $display['display_options']['path'] . '?_format=json';
      }
    }
  }
  catch (Exception $exception) {
    watchdog_exception('alert_banner', $exception);
  }

  $library = ['alert_banner/alert_banner'];
  $css_classes = 'alert-banners';

  if ($settings->get('au_dta_design_system')) {
    $css_classes .= ' au-grid au-body';
    $library[] = 'alert_banner/alert_banner_au_dta';
  }

  $page_top['alert_banners'] = [
    '#markup' => '<div class="' . $css_classes . '" data-alert-endpoint="' . $endpoint . '"></div>',
    '#attached' => [
      'library' => $library,
    ],
    '#cache' => [
      'tags' => ['config:views.view.alert_banners'],
    ],
  ];
}