file.api.php

<?php


/**
 * @file
 * Hooks related to the File management system.
 */

use Drupal\Core\StreamWrapper\StreamWrapperManager;

/**
 * @addtogroup hooks
 * @{
 */

/**
 * Control access to private file downloads and specify HTTP headers.
 *
 * This hook allows modules to enforce permissions on file downloads whenever
 * Drupal is handling file download, as opposed to the web server bypassing
 * Drupal and returning the file from a public directory. Modules can also
 * provide headers to specify information like the file's name or MIME type.
 *
 * @param string $uri
 *   The URI of the file.
 *
 * @return string[]|int|null
 *   If the user does not have permission to access the file, return -1. If the
 *   user has permission, return an array with the appropriate headers. If the
 *   file is not controlled by the current module, the return value should be
 *   NULL.
 *
 * @see \Drupal\system\FileDownloadController::download()
 */
function hook_file_download($uri) : array|int|null {
  // Check to see if this is a config download.
  $scheme = StreamWrapperManager::getScheme($uri);
  $target = StreamWrapperManager::getTarget($uri);
  if ($scheme == 'temporary' && $target == 'config.tar.gz') {
    return [
      'Content-disposition' => 'attachment; filename="config.tar.gz"',
    ];
  }
  return NULL;
}

/**
 * Alter the URL to a file.
 *
 * This hook is called from \Drupal\Core\File\FileUrlGenerator::generate(),
 * and is called fairly frequently (10+ times per page), depending on how many
 * files there are in a given page.
 * If CSS and JS aggregation are disabled, this can become very frequently
 * (50+ times per page) so performance is critical.
 *
 * This function should alter the URI, if it wants to rewrite the file URL.
 *
 * @param string $uri
 *   The URI to a file for which we need an external URL, or the path to a
 *   shipped file.
 */
function hook_file_url_alter(&$uri) {
  $user = \Drupal::currentUser();
  // User 1 will always see the local file in this example.
  if ($user->id() == 1) {
    return;
  }
  $cdn1 = 'http://cdn1.example.com';
  $cdn2 = 'http://cdn2.example.com';
  $cdn_extensions = [
    'css',
    'js',
    'gif',
    'jpg',
    'jpeg',
    'png',
  ];
  // Most CDNs don't support private file transfers without a lot of hassle,
  // so don't support this in the common case.
  $schemes = [
    'public',
  ];
  /** @var \Drupal\Core\StreamWrapper\StreamWrapperManagerInterface $stream_wrapper_manager */
  $stream_wrapper_manager = \Drupal::service('stream_wrapper_manager');
  $scheme = $stream_wrapper_manager::getScheme($uri);
  // Only serve shipped files and public created files from the CDN.
  if (!$scheme || in_array($scheme, $schemes)) {
    // Shipped files.
    if (!$scheme) {
      $path = $uri;
    }
    else {
      $wrapper = $stream_wrapper_manager->getViaScheme($scheme);
      $path = $wrapper->getDirectoryPath() . '/' . $stream_wrapper_manager::getTarget($uri);
    }
    // Clean up Windows paths.
    $path = str_replace('\\', '/', $path);
    // Serve files with one of the CDN extensions from CDN 1, all others from
    // CDN 2.
    $pathinfo = pathinfo($path);
    if (isset($pathinfo['extension']) && in_array($pathinfo['extension'], $cdn_extensions)) {
      $uri = $cdn1 . '/' . $path;
    }
    else {
      $uri = $cdn2 . '/' . $path;
    }
  }
}

/**
 * Alter MIME type mappings used to determine MIME type from a file extension.
 *
 * @param array $mapping
 *   An array of mimetypes correlated to the extensions that relate to them.
 *   The array has 'mimetypes' and 'extensions' elements, each of which is an
 *   array.
 *
 * @deprecated in drupal:11.2.0 and is removed from drupal:12.0.0. Create a
 *   \Drupal\Core\File\Event\MimeTypeMapLoadedEvent subscriber instead.
 *
 * It is used to allow modules to add to or modify the default mapping of
 * MIME type to file extensions.
 *
 * @see https://www.drupal.org/node/3494040
 * @see \Drupal\Core\File\EventSubscriber\LegacyMimeTypeMapLoadedSubscriber
 * @see \Drupal\Core\File\MimeType\ExtensionMimeTypeGuesser::guessMimeType()
 * @see \Drupal\Core\File\MimeType\ExtensionMimeTypeGuesser::$defaultMapping
 */
function hook_file_mimetype_mapping_alter(&$mapping) {
  // Add new MIME type 'drupal/info'.
  $mapping['mimetypes']['example_info'] = 'drupal/info';
  // Add new extension '.info.yml' and map it to the 'drupal/info' MIME type.
  $mapping['extensions']['info'] = 'example_info';
  // Override existing extension mapping for '.ogg' files.
  $mapping['extensions']['ogg'] = 189;
}

/**
 * @} End of "addtogroup hooks".
 */