Add refresh-interval to exported calendars

Signed-off-by: Georg Ehrke <developer@georgehrke.com>

1 files changed, 97 insertions, 0 deletions

diff --git a/apps/dav/lib/CalDAV/ICSExportPlugin/ICSExportPlugin.php b/apps/dav/lib/CalDAV/ICSExportPlugin/ICSExportPlugin.php
new file mode 100644
index 00000000000..3fe8477a0aa
--- /dev/null
+++ b/apps/dav/lib/CalDAV/ICSExportPlugin/ICSExportPlugin.php
@@ -0,0 +1,97 @@
+<?php
+/**
+ * @copyright 2019, Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @author Georg Ehrke <oc.list@georgehrke.com>
+ *
+ * @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\DAV\CalDAV\ICSExportPlugin;
+
+use OCP\IConfig;
+use OCP\ILogger;
+use Sabre\HTTP\ResponseInterface;
+use Sabre\VObject\DateTimeParser;
+use Sabre\VObject\InvalidDataException;
+use Sabre\VObject\Property\ICalendar\Duration;
+
+/**
+ * Class ICSExportPlugin
+ *
+ * @package OCA\DAV\CalDAV\ICSExportPlugin
+ */
+class ICSExportPlugin extends \Sabre\CalDAV\ICSExportPlugin {
+
+	/** @var IConfig */
+	private $config;
+
+	/** @var ILogger */
+	private $logger;
+
+	/** @var string */
+	private const DEFAULT_REFRESH_INTERVAL = 'PT4H';
+
+	/**
+	 * ICSExportPlugin constructor.
+	 *
+	 * @param IConfig $config
+	 */
+	public function __construct(IConfig $config, ILogger $logger) {
+		$this->config = $config;
+		$this->logger = $logger;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	protected function generateResponse($path, $start, $end, $expand, $componentType, $format, $properties, ResponseInterface $response) {
+		if (!isset($properties['{http://nextcloud.com/ns}refresh-interval'])) {
+			$value = $this->config->getAppValue('dav', 'defaultRefreshIntervalExportedCalendars', self::DEFAULT_REFRESH_INTERVAL);
+			$properties['{http://nextcloud.com/ns}refresh-interval'] = $value;
+		}
+
+		return parent::generateResponse($path, $start, $end, $expand, $componentType, $format, $properties, $response);
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function mergeObjects(array $properties, array $inputObjects) {
+		$vcalendar = parent::mergeObjects($properties, $inputObjects);
+
+		if (isset($properties['{http://nextcloud.com/ns}refresh-interval'])) {
+			$refreshIntervalValue = $properties['{http://nextcloud.com/ns}refresh-interval'];
+			try {
+				DateTimeParser::parseDuration($refreshIntervalValue);
+			} catch (InvalidDataException $ex) {
+				$this->logger->debug('Invalid refresh interval for exported calendar, falling back to default value ...');
+				$refreshIntervalValue = self::DEFAULT_REFRESH_INTERVAL;
+			}
+
+			// https://tools.ietf.org/html/rfc7986#section-5.7
+			$refreshInterval = new Duration($vcalendar, 'REFRESH-INTERVAL', $refreshIntervalValue);
+			$refreshInterval->add('VALUE', 'DURATION');
+			$vcalendar->add($refreshInterval);
+
+			// Legacy property for compatibility
+			$vcalendar->{'X-PUBLISHED-TTL'} = $refreshIntervalValue;
+		}
+
+		return $vcalendar;
+	}
+
+}