function file_stream_wrapper_valid_scheme

Checks that the scheme of a stream URI is valid.

Confirms that there is a registered stream handler for the provided scheme and that it is callable. This is useful if you want to confirm a valid scheme without creating a new instance of the registered handler.


$scheme: A URI scheme, a stream is referenced as "scheme://target".

Return value

Returns TRUE if the string is the name of a validated stream, or FALSE if the scheme does not have a registered handler.

Related topics

13 calls to file_stream_wrapper_valid_scheme()
drupal_dirname in drupal/includes/
Gets the name of the directory from a given path.
drupal_rmdir in drupal/includes/
Removes a directory.
drupal_tempnam in drupal/includes/
Creates a file with a unique filename in the specified directory.
drupal_unlink in drupal/includes/
Deletes a file.
file_download in drupal/includes/
Menu handler for private file transfers.

... See full list


drupal/includes/, line 218
API for handling file uploads and server file management.


function file_stream_wrapper_valid_scheme($scheme) {

  // Does the scheme have a registered handler that is callable?
  $class = file_stream_wrapper_get_class($scheme);
  if (class_exists($class)) {
    return TRUE;
  else {
    return FALSE;