Often an app wants to store data. However not all data that is stored belongs with the users files. Often you just want a very simple storage to have some temp files. In order to facilitate this there is the AppData folder that provides each app with a private simple filesystem.

Usage is almost trivial when your app is using the AppFramework.


namespace OCA\MyApp\Controller\MyController;

use OCP\AppFramework\Controller;
use OCP\Files\IAppData;
use OCP\IRequest;

class MyController extends Controller {
    /** @var IAppData */
    private $appData;

    public function __construct($appName,
                                IRequest $request,
                                IAppData $appData) {
        parent::__construct($appName, $request);
        $this->appData = $appData;

This gives your controller access to the IAppData simple filesystem of your app.

The simple filesystem

The IAppData uses the simple filesystem. This is a very simplified filesystem that will allow for easy mapping to for example memcaches. The filesystem has three elements: root, folder, file.

The root can only contain folders. And each folder can only contain files. This is limited to keep things simple and to allow easy mapping to other backends. For example a sysadmin might chose to map the avatars to fast storage since they are used often.