function drupal_get_filename

drupal_get_filename($type, $name, $filename = NULL)

Returns and optionally sets the filename for a system resource.

The filename, whether provided, cached, or retrieved from the database, is only returned if the file exists.

This function plays a key role in allowing Drupal's resources (modules and themes) to be located in different places depending on a site's configuration. For example, a module 'foo' may legally be located in any of these three places:

core/modules/foo/foo.info.yml modules/foo/foo.info.yml sites/example.com/modules/foo/foo.info.yml

Calling drupal_get_filename('module', 'foo') will give you one of the above, depending on where the module is located.

Parameters

$type: The type of the item; one of 'core', 'profile', 'module', 'theme', or 'theme_engine'.

$name: The name of the item for which the filename is requested. Ignored for $type 'core'.

$filename: The filename of the item if it is to be set explicitly rather than by consulting the database.

Return value

The filename of the requested item or NULL if the item is not found.

File

core/includes/bootstrap.inc, line 191

Functions that need to be loaded on every Drupal request.

Code

function drupal_get_filename($type, $name, $filename = NULL) {
  // The location of files will not change during the request, so do not use
  // drupal_static().
  static $files = array();

  // Type 'core' only exists to simplify application-level logic; it always maps
  // to the /core directory, whereas $name is ignored. It is only requested via
  // drupal_get_path(). /core/core.info.yml does not exist, but is required
  // since drupal_get_path() returns the dirname() of the returned pathname.
  if ($type === 'core') {
    return 'core/core.info.yml';
  }

  // Profiles are converted into modules in system_rebuild_module_data().
  // @todo Remove false-exposure of profiles as modules.
  if ($type == 'profile') {
    $type = 'module';
  }
  if (!isset($files[$type])) {
    $files[$type] = array();
  }

  if (isset($filename)) {
    $files[$type][$name] = $filename;
  }
  elseif (!isset($files[$type][$name])) {
    // If the pathname of the requested extension is not known, try to retrieve
    // the list of extension pathnames from various providers, checking faster
    // providers first.
    // Retrieve the current module list (derived from the service container).
    if ($type == 'module' && \Drupal::hasService('module_handler')) {
      foreach (\Drupal::moduleHandler()->getModuleList() as $module_name => $module) {
        $files[$type][$module_name] = $module->getPathname();
      }
    }
    // If still unknown, retrieve the file list prepared in state by
    // system_rebuild_module_data() and
    // \Drupal\Core\Extension\ThemeHandlerInterface::rebuildThemeData().
    if (!isset($files[$type][$name]) && \Drupal::hasService('state')) {
      $files[$type] += \Drupal::state()->get('system.' . $type . '.files', array());
    }
    // If still unknown, create a user-level error message.
    if (!isset($files[$type][$name])) {
      trigger_error(SafeMarkup::format('The following @type is missing from the file system: @name', array('@type' => $type, '@name' => $name)), E_USER_WARNING);
    }
  }

  if (isset($files[$type][$name])) {
    return $files[$type][$name];
  }
}