function file_download_headers

Retrieves headers for a private file download.

Calls all module implementations of hook_file_download() to retrieve headers for files by the module that originally provided the file. The presence of returned headers indicates the current user has access to the file.

Parameters

$uri: The URI for the file whose headers should be retrieved.

Return value

If access is allowed, headers for the file, suitable for passing to: file_transfer(). If access is not allowed, an empty array will be returned.

See also

file_transfer()

file_download_access()

hook_file_download()

Related topics

File

core/includes/file.inc, line 2273

API for handling file uploads and server file management.

Code

function file_download_headers($uri) {
  // Let other modules provide headers and control access to the file.
  // module_invoke_all() uses array_merge_recursive() which merges header
  // values into a new array. To avoid that and allow modules to override
  // headers instead, use array_merge() to merge the returned arrays.
  $headers = array();
  foreach (module_implements('file_download') as $module) {
    $function = $module . '_file_download';
    $result = $function($uri);
    if ($result == -1) {
      // Throw away the headers received so far.
      $headers = array();
      break;
    }
    if (isset($result) && is_array($result)) {
      $headers = array_merge($headers, $result);
    }
  }
  return $headers;
}