function drupal_get_filename

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

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:

modules/foo/foo.module sites/all/modules/foo/foo.module sites/example.com/modules/foo/foo.module

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 (theme, theme_engine, module, profile).

$name: The name of the item for which the filename is requested.

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

bool $trigger_error: Whether to trigger an error when a file is missing or has unexpectedly moved. This defaults to TRUE, but can be set to FALSE by calling code that merely wants to check whether an item exists in the filesystem.

Return value

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

File

includes/bootstrap.inc, line 839
Functions that need to be loaded on every Drupal request.

Code

function drupal_get_filename($type, $name, $filename = NULL, $trigger_error = TRUE) {
  // The $files static variable will hold the locations of all requested files.
  // We can be sure that any file listed in this static variable actually
  // exists as all additions have gone through a file_exists() check.
  // The location of files will not change during the request, so do not use
  // drupal_static().
  static $files = array();

  // Profiles are a special case: they have a fixed location and naming.
  if ($type == 'profile') {
    $profile_filename = "profiles/$name/$name.profile";
    $files[$type][$name] = file_exists($profile_filename) ? $profile_filename : FALSE;
  }
  if (!isset($files[$type])) {
    $files[$type] = array();
  }

  if (!empty($filename) && file_exists($filename)) {
    // Prime the static cache with the provided filename.
    $files[$type][$name] = $filename;
  }
  elseif (isset($files[$type][$name])) {
    // This item had already been found earlier in the request, either through
    // priming of the static cache (for example, in system_list()), through a
    // lookup in the {system} table, or through a file scan (cached or not). Do
    // nothing.
  }
  else {
    // Look for the filename listed in the {system} table. Verify that we have
    // an active database connection before doing so, since this function is
    // called both before we have a database connection (i.e. during
    // installation) and when a database connection fails.
    $database_unavailable = TRUE;
    try {
      if (function_exists('db_query')) {
        $file = db_query("SELECT filename FROM {system} WHERE name = :name AND type = :type", array(':name' => $name, ':type' => $type))->fetchField();
        if ($file !== FALSE && file_exists(DRUPAL_ROOT . '/' . $file)) {
          $files[$type][$name] = $file;
        }
        $database_unavailable = FALSE;
      }
    }
    catch (Exception $e) {
      // The database table may not exist because Drupal is not yet installed,
      // the database might be down, or we may have done a non-database cache
      // flush while $conf['page_cache_without_database'] = TRUE and
      // $conf['page_cache_invoke_hooks'] = TRUE. We have a fallback for these
      // cases so we hide the error completely.
    }
    // Fall back to searching the filesystem if the database could not find the
    // file or the file does not exist at the path returned by the database.
    if (!isset($files[$type][$name])) {
      $files[$type][$name] = _drupal_get_filename_fallback($type, $name, $trigger_error, $database_unavailable);
    }
  }

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

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Licensed under the GNU General Public License, version 2 and later.
Drupal is a registered trademark of Dries Buytaert.
https://api.drupal.org/api/drupal/includes!bootstrap.inc/function/drupal_get_filename/7.x