Page callback: Handles private file transfers.
Call modules that implement hook_file_download() to find out if a file is accessible and what headers it should be transferred with. If one or more modules returned headers the download will start with the returned headers. If a module returns -1 an AccessDeniedHttpException will be thrown. If the file exists but no modules responded an AccessDeniedHttpException will be thrown.If the file does not exist a NotFoundHttpException will be thrown.
function file_download() {
// Merge remaining path arguments into relative file path.
$args = func_get_args();
$scheme = array_shift($args);
$target = implode('/', $args);
$uri = $scheme . '://' . $target;
if (file_stream_wrapper_valid_scheme($scheme) && file_exists($uri)) {
// Let other modules provide headers and controls access to the file.
$headers = module_invoke_all('file_download', $uri);
foreach ($headers as $result) {
if ($result == -1) {
throw new AccessDeniedHttpException();
}
}
if (count($headers)) {
return new BinaryFileResponse($uri, 200, $headers);
}
throw new AccessDeniedHttpException();
}
throw new NotFoundHttpException();
}