AppData
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.
<?php
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.
Root
The root element can only contain folders. There are 3 things you can do on a root element:
getFolder: get the folder you request
newFolder: creates a new folder
getDirectoryListing: lists all the folders in this root
Folder
A folder has a bit more options.
getDirectoryListing: lists all the files in the folder
fileExists: check if a file exists
getFile: get a file
newFile: create a new file
delete: delete a folder and its content
getName: get the name of the folder
File
getName: get the name of the file
getSize: get the size of the file
getETag: get the ETag of the file
getMTime: get the modification time of the file
getContent: get the content of the file
putContent: write content to the file
delete: delete the file
getMimeType: get the mimetype of the file
read: get a resource for reading the file
write: get a resource for writing to the file