Add change database helper

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

lib/Db/ChangeHelper.php

@@ -0,0 +1,91 @@
+<?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\Db;
+
+use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\ICache;
+use OCP\ICacheFactory;
+use OCP\IDBConnection;
+use OCP\IRequest;
+use OCP\IUserManager;
+use OCP\IGroupManager;
+
+class ChangeHelper {
+
+	const TYPE_BOARD = 'boardChanged';
+	const TYPE_CARD = 'cardChanged';
+
+	private $db;
+
+	public function __construct(
+		IDBConnection $db,
+		ICacheFactory $cacheFactory,
+		IRequest $request
+	) {
+		$this->db = $db;
+		$this->cache = $cacheFactory->createDistributed('deck_changes');
+		$this->request = $request;
+	}
+
+	public function boardChanged($boardId) {
+		$time = time();
+		$etag = md5($time . microtime());
+		$this->cache->set(self::TYPE_BOARD . '-' . $boardId, $etag);
+		$sql  = 'UPDATE `*PREFIX*deck_boards` SET `last_modified` = ? WHERE `id` = ?';
+		$this->db->executeUpdate($sql, [$time, $boardId]);
+	}
+
+	public function cardChanged($cardId, $updateCard = true) {
+		$time = time();
+		$etag = md5($time . microtime());
+		$this->cache->set(self::TYPE_CARD . '-' .$cardId, $etag);
+		if ($updateCard) {
+			$sql = 'UPDATE `*PREFIX*deck_cards` SET `last_modified` = ? WHERE `id` = ?';
+			$this->db->executeUpdate($sql, [time(), $cardId]);
+		}
+
+		$sql = 'SELECT s.board_id as id FROM oc_deck_stacks as s inner join oc_deck_cards as c ON c.stack_id = s.id WHERE c.id = ?';
+		$result = $this->db->executeQuery($sql, [$cardId]);
+		if ($row = $result->fetch()) {
+			$this->boardChanged($row['id']);
+		}
+	}
+
+	public function checkEtag($type, $id) {
+		$etag = $this->getEtag($type, $id);
+		if ($this->request->getHeader('If-None-Match') === $etag) {
+			return true;
+		}
+		return false;
+	}
+
+	public function getEtag($type, $id) {
+		$entry = $this->cache->get($type . '-' .$id);
+		if ($entry === 'null') {
+			return '';
+		}
+		return $entry;
+	}
+
+}

lib/Db/Stack.php

@@ -28,9 +28,9 @@ class Stack extends RelationalEntity {
 	protected $title;
 	protected $boardId;
 	protected $deletedAt = 0;
+	protected $lastModified = 0;
 	protected $cards = array();
 	protected $order;
-	protected $lastModified = 0;
 
 	public function __construct() {
 		$this->addType('id', 'integer');