Implement attachment backend with a first module for app data file upload

Signed-off-by: Julius Härtl <jus@bitgrid.net>

lib/Service/IAttachmentService.php

@@ -0,0 +1,84 @@
+<?php
+/**
+ * @copyright Copyright (c) 2018 Julius Härtl <jus@bitgrid.net>
+ *
+ * @author Julius Härtl <jus@bitgrid.net>
+ *
+ * @license GNU AGPL version 3 or any later version
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+namespace OCA\Deck\Service;
+
+
+use OCA\Deck\Db\Attachment;
+use OCP\AppFramework\Http\Response;
+
+/**
+ * Interface IAttachmentService
+ *
+ * Implement this interface to extend the default attachment behaviour
+ * This interface allows to extend/reduce the data stored with an attachment,
+ * as well as rendering a custom output per attachment type
+ *
+ */
+interface IAttachmentService {
+
+	/**
+	 * Add extended data to the returned data of an attachment
+	 *
+	 * @param Attachment $attachment
+	 * @return mixed
+	 */
+	public function extendData(Attachment $attachment);
+
+	/**
+	 * Display the attachment
+	 *
+	 * TODO: Move to IAttachmentDisplayService for better separation
+	 *
+	 * @param Attachment $attachment
+	 * @return Response
+	 */
+	public function display(Attachment $attachment);
+
+	/**
+	 * Create a new attachment
+	 *
+	 * This method will be called before inserting the attachment entry in the database
+	 *
+	 * @param Attachment $attachment
+	 */
+	public function create(Attachment $attachment);
+
+	/**
+	 * Update an attachment with custom data
+	 *
+	 * This method will be called before updating the attachment entry in the database
+	 *
+	 * @param Attachment $attachment
+	 */
+	public function update(Attachment $attachment);
+
+	/**
+	 * Delete an attachment
+	 *
+	 * This method will be called before removing the attachment entry from the database
+	 *
+	 * @param Attachment $attachment
+	 */
+	public function delete(Attachment $attachment);
+}