cdn.module in CDN 8.3

Provides integration with CDNs for files.

File

cdn.module

<?php

/**
 * @file
 * Provides integration with CDNs for files.
 */
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\editor\Entity\Editor;

/**
 * Implements hook_help().
 */
function cdn_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.cdn':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('The CDN module can serve files (CSS, JavaScript, images, fonts, videos …) from a <abbr title="Content Delivery Network">CDN</abbr> instead of your web server(s). For more information, see the <a href=":online">online documentation for the CDN module</a>.', [
        ':online' => 'https://www.drupal.org/docs/8/managing-site-performance-and-scalability/content-delivery-network-cdn',
      ]) . '</p>';
      $output .= '<h3>' . t('Uses') . '</h3>';
      $output .= '<dl>';
      $output .= '<dt>' . t('General') . '</dt>';
      $output .= '<dd>' . t('A content delivery network is a collection of web servers distributed across multiple locations around the world to deliver content more efficiently to users. The server selected for delivering content to a specific user is typically based on a measure of network proximity. For more information, see <a href="http://wimleers.com/article/key-properties-of-a-cdn"><q>Key Properties of a CDN</q>.</a>') . '</dd>';
      $output .= '<dt>' . t('Improving performance') . '</dt>';
      $output .= '<dd>' . t('Because a CDN automatically serves files from the location that is closest to the end user, files can be downloaded by end users faster. It can be faster in two ways: downloads start faster (lower latency) and downloads complete faster (higher bandwidth).') . '</dd>';
      $output .= '<dt>' . t('Reducing server load & costs') . '</dt>';
      $output .= '<dd>' . t('By letting a CDN serve files instead of your webserver(s), it is possible to significantly reduce the load on your server and its costs. Note that it may just as well end up costing more — it depends on pricing of the CDN and your server(s).') . '</dd>';
      $output .= '</dl>';
      return $output;
  }
}

/**
 * Implements hook_file_url_alter().
 */
function cdn_file_url_alter(&$uri) {

  // Gracefully handle invalid invocations of file_create_url().
  // @todo Remove when requiring Drupal 9.3.
  // @see https://www.drupal.org/project/drupal/issues/2669074
  if (empty($uri) || !is_string($uri)) {
    \Drupal::logger('php')
      ->warning('A caller of file_create_url() did not pass a file URI.');
    return;
  }

  // Don't alter file URLs when running update.php.
  // @todo Remove the second condition after the CDN module requires the Drupal core minor that ships with https://www.drupal.org/project/drupal/issues/2969056
  if (defined('MAINTENANCE_MODE') || stripos($_SERVER['PHP_SELF'], 'update.php') !== FALSE) {
    return;
  }

  // Don't alter CSS file URLs while settings.php is disabling CSS aggregation.
  if (substr($uri, -4) === '.css' && isset($GLOBALS['config']['system.performance']['css']['preprocess']) && $GLOBALS['config']['system.performance']['css']['preprocess'] === FALSE) {
    return;
  }

  // Don't serve CKEditor from a CDN when far future future is enabled (CKEditor
  // insists on computing other assets to load based on this URL).
  if ($uri === 'core/assets/vendor/ckeditor/ckeditor.js' && \Drupal::service('cdn.settings')
    ->farfutureIsEnabled()) {
    return;
  }

  // Don't alter file URLs while processing a CSS file.
  // @see \Drupal\cdn\Asset\CssOptimizer
  global $_cdn_in_css_file;
  if ($_cdn_in_css_file) {
    return;
  }
  $result = \Drupal::service('cdn.file_url_generator')
    ->generate($uri);
  if ($result) {
    $uri = $result;
  }
}

/**
 * Implements hook_editor_js_settings_alter().
 */
function cdn_editor_js_settings_alter(array &$settings) {
  if (!\Drupal::moduleHandler()
    ->moduleExists('ckeditor')) {
    return;
  }

  // Don't serve CKEditor plugins from a CDN when far future future is enabled
  // (CKEditor insists on computing other assets to load based on these URLs).
  if (!\Drupal::service('cdn.settings')
    ->farfutureIsEnabled()) {
    return;
  }
  global $_cdn_in_css_file;
  $_cdn_in_css_file = TRUE;
  $ckeditor_plugin_manager = \Drupal::service('plugin.manager.ckeditor.plugin');
  $root_relative_file_url = function ($uri) {
    return file_url_transform_relative(file_create_url($uri));
  };
  foreach ($settings['editor']['formats'] as $format => &$format_settings) {
    if ($format_settings['editor'] === 'ckeditor') {
      $editor = Editor::load($format);

      // @see \Drupal\ckeditor\Plugin\Editor\CKEditor::getJSSettings()
      $external_plugin_files = $ckeditor_plugin_manager
        ->getEnabledPluginFiles($editor);
      $format_settings['editorSettings']['drupalExternalPlugins'] = array_map($root_relative_file_url, $external_plugin_files);
    }
  }
  $_cdn_in_css_file = FALSE;
}

Functions

Name	Description
cdn_editor_js_settings_alter	Implements hook_editor_js_settings_alter().
cdn_file_url_alter	Implements hook_file_url_alter().
cdn_help	Implements hook_help().