function FileDownloadHook::__invoke

Implements hook_file_download().

File

core/modules/file/src/Hook/FileDownloadHook.php, line 28

Class

FileDownloadHook

Implements hook_file_download().

Namespace

Code

public function __invoke($uri) : array|int|null {
    // Get the file record based on the URI. If not in the database just return.
    $file = $this->fileRepository
        ->loadByUri($uri);
    if (!$file) {
        return NULL;
    }
    // Find out if a temporary file is still used in the system.
    if ($file->isTemporary()) {
        $usage = $this->fileUsage
            ->listUsage($file);
        if (empty($usage) && $file->getOwnerId() != $this->currentUser
            ->id()) {
            // Deny access to temporary files without usage that are not owned by
            // the same user. This prevents the security issue that a private file
            // that was protected by field permissions becomes available after its
            // usage was removed and before it is actually deleted from the file
            // system. Modules that depend on this behavior should make the file
            // permanent instead.
            return -1;
        }
    }
    // Find out which (if any) fields of this type contain the file.
    $references = file_get_file_references($file, NULL, EntityStorageInterface::FIELD_LOAD_CURRENT, NULL);
    // Stop processing if there are no references in order to avoid returning
    // headers for files controlled by other modules. Make an exception for
    // temporary files where the host entity has not yet been saved (for
    // example, an image preview on a node/add form) in which case, allow
    // download by the file's owner.
    if (empty($references) && ($file->isPermanent() || $file->getOwnerId() != $this->currentUser
        ->id())) {
        return NULL;
    }
    if (!$file->access('download')) {
        return -1;
    }
    // Access is granted.
    return $file->getDownloadHeaders();
}