Use ISO8601 timestamps for the CalDAV trashbin

Signed-off-by: Christoph Wurst <[email protected]>

apps/dav/lib/CalDAV/Calendar.php

@@ -28,6 +28,9 @@
  */
 namespace OCA\DAV\CalDAV;
 
+use DateTimeImmutable;
+use DateTimeInterface;
+use OCA\DAV\CalDAV\Trashbin\Plugin as TrashbinPlugin;
 use OCA\DAV\DAV\Sharing\IShareable;
 use OCA\DAV\Exception\UnsupportedLimitOnInitialSyncException;
 use OCP\IConfig;
@@ -63,6 +66,13 @@ class Calendar extends \Sabre\CalDAV\Calendar implements IRestorable, IShareable
 	 * @param IConfig $config
 	 */
 	public function __construct(BackendInterface $caldavBackend, $calendarInfo, IL10N $l10n, IConfig $config) {
+		// Convert deletion date to ISO8601 string
+		if (isset($calendarInfo[TrashbinPlugin::PROPERTY_DELETED_AT])) {
+			$calendarInfo[TrashbinPlugin::PROPERTY_DELETED_AT] = (new DateTimeImmutable())
+				->setTimestamp($calendarInfo[TrashbinPlugin::PROPERTY_DELETED_AT])
+				->format(DateTimeInterface::ATOM);
+		}
+
 		parent::__construct($caldavBackend, $calendarInfo);
 
 		if ($this->getName() === BirthdayService::BIRTHDAY_CALENDAR_URI) {

apps/dav/lib/CalDAV/Trashbin/Plugin.php

@@ -26,6 +26,8 @@
 namespace OCA\DAV\CalDAV\Trashbin;
 
 use Closure;
+use DateTimeImmutable;
+use DateTimeInterface;
 use OCA\DAV\CalDAV\Calendar;
 use OCA\DAV\CalDAV\RetentionService;
 use OCP\IRequest;
@@ -101,7 +103,14 @@ private function propFind(
 		INode $node): void {
 		if ($node instanceof DeletedCalendarObject) {
 			$propFind->handle(self::PROPERTY_DELETED_AT, function () use ($node) {
-				return $node->getDeletedAt();
+				$ts = $node->getDeletedAt();
+				if ($ts === null) {
+					return null;
+				}
+
+				return (new DateTimeImmutable())
+					->setTimestamp($ts)
+					->format(DateTimeInterface::ATOM);
 			});
 			$propFind->handle(self::PROPERTY_CALENDAR_URI, function () use ($node) {
 				return $node->getCalendarUri();