fix(caldav): event search with limit and timerange

nextcloud · May 7, 2024 · d335b1b · d335b1b
1 parent 6fc2c47
commit d335b1b
Showing 1 changed file with 105 additions and 47 deletions.
diff --git a/apps/dav/lib/CalDAV/CalDavBackend.php b/apps/dav/lib/CalDAV/CalDavBackend.php
@@ -1914,14 +1914,34 @@ public function search(
 					$this->db->escapeLikeParameter($pattern) . '%')));
 		}
 
+		$start = null;
+		$end = null;
+
+		$hasLimit = is_int($limit);
+		$hasTimeRange = false;
+
 		if (isset($options['timerange'])) {
 			if (isset($options['timerange']['start']) && $options['timerange']['start'] instanceof DateTimeInterface) {
-				$outerQuery->andWhere($outerQuery->expr()->gt('lastoccurence',
-					$outerQuery->createNamedParameter($options['timerange']['start']->getTimeStamp())));
+				/** @var DateTimeInterface $start */
+				$start = $options['timerange']['start'];
+				$outerQuery->andWhere(
+					$outerQuery->expr()->gt(
+						'lastoccurence',
+						$outerQuery->createNamedParameter($start->getTimestamp())
+					)
+				);
+				$hasTimeRange = true;
 			}
 			if (isset($options['timerange']['end']) && $options['timerange']['end'] instanceof DateTimeInterface) {
-				$outerQuery->andWhere($outerQuery->expr()->lt('firstoccurence',
-					$outerQuery->createNamedParameter($options['timerange']['end']->getTimeStamp())));
+				/** @var DateTimeInterface $end */
+				$end = $options['timerange']['end'];
+				$outerQuery->andWhere(
+					$outerQuery->expr()->lt(
+						'firstoccurence',
+						$outerQuery->createNamedParameter($end->getTimestamp())
+					)
+				);
+				$hasTimeRange = true;
 			}
 		}
 
@@ -1940,52 +1960,43 @@ public function search(
 
 		$outerQuery->andWhere($outerQuery->expr()->in('c.id', $outerQuery->createFunction($innerQuery->getSQL())));
 
-		if ($offset) {
-			$outerQuery->setFirstResult($offset);
-		}
-		if ($limit) {
-			$outerQuery->setMaxResults($limit);
+		if ($offset === null) {
+			$offset = 0;
+		}
+
+		if ($hasLimit && $hasTimeRange) {
+			/**
+			 * Event recurrences are evaluated at runtime because the database only knows the first and last occurrence.
+			 *
+			 * Given, a user created 8 events with a yearly reoccurrence and two for events tomorrow.
+			 * The upcoming event widget asks the CalDAV backend for 7 events within the next 14 days.
+			 *
+			 * If limit 7 is applied to the SQL query, we find the 7 events with a yearly reoccurrence
+			 * and discard the events after evaluating the reoccurrence rules because they are not due within
+			 * the next 14 days and end up with an empty result even if there are two events to show.
+			 *
+			 * The workaround for search requests with limit and time range is ask for more row than requested
+			 * and retry if we have not reached the limit.
+			 *
+			 * 25 rows and 3 retries is entirely arbitrary.
+			 * Send us a patch if you have something different in mind.
+			 */
+			$maxResults = max($limit, 25);
+			$attempts = 3;
+		} else {
+			$maxResults = $limit;
+			$attempts = 1;
 		}
 
-		$result = $outerQuery->executeQuery();
-		$calendarObjects = [];
-		while (($row = $result->fetch()) !== false) {
-			$start = $options['timerange']['start'] ?? null;
-			$end = $options['timerange']['end'] ?? null;
-
-			if ($start === null || !($start instanceof DateTimeInterface) || $end === null || !($end instanceof DateTimeInterface)) {
-				// No filter required
-				$calendarObjects[] = $row;
-				continue;
-			}
+		$outerQuery->setFirstResult($offset);
+		$outerQuery->setMaxResults($maxResults);
 
-			$isValid = $this->validateFilterForObject($row, [
-				'name' => 'VCALENDAR',
-				'comp-filters' => [
-					[
-						'name' => 'VEVENT',
-						'comp-filters' => [],
-						'prop-filters' => [],
-						'is-not-defined' => false,
-						'time-range' => [
-							'start' => $start,
-							'end' => $end,
-						],
-					],
-				],
-				'prop-filters' => [],
-				'is-not-defined' => false,
-				'time-range' => null,
-			]);
-			if (is_resource($row['calendardata'])) {
-				// Put the stream back to the beginning so it can be read another time
-				rewind($row['calendardata']);
-			}
-			if ($isValid) {
-				$calendarObjects[] = $row;
-			}
-		}
-		$result->closeCursor();
+		$calendarObjects = [];
+		do {
+			$objectsCount = array_push($calendarObjects, ...$this->searchCalendarObjectsByQuery($outerQuery, $start, $end));
+			$outerQuery->setFirstResult($offset += $maxResults);
+			--$attempts;
+		} while ($attempts > 0 && $objectsCount < $limit);
 
 		return array_map(function ($o) use ($options) {
 			$calendarData = Reader::read($o['calendardata']);
@@ -2025,6 +2036,53 @@ public function search(
 		}, $calendarObjects);
 	}
 
+	private function searchCalendarObjectsByQuery(IQueryBuilder $query, DateTimeInterface|null $start, DateTimeInterface|null $end): array {
+		$calendarObjects = [];
+		$filterByTimeRange = ($start instanceof DateTimeInterface) || ($end instanceof DateTimeInterface);
+
+		$result = $query->executeQuery();
+
+		while (($row = $result->fetch()) !== false) {
+			if ($filterByTimeRange === false) {
+				// No filter required
+				$calendarObjects[] = $row;
+				continue;
+			}
+
+			$isValid = $this->validateFilterForObject($row, [
+				'name' => 'VCALENDAR',
+				'comp-filters' => [
+					[
+						'name' => 'VEVENT',
+						'comp-filters' => [],
+						'prop-filters' => [],
+						'is-not-defined' => false,
+						'time-range' => [
+							'start' => $start,
+							'end' => $end,
+						],
+					],
+				],
+				'prop-filters' => [],
+				'is-not-defined' => false,
+				'time-range' => null,
+			]);
+
+			if (is_resource($row['calendardata'])) {
+				// Put the stream back to the beginning so it can be read another time
+				rewind($row['calendardata']);
+			}
+
+			if ($isValid) {
+				$calendarObjects[] = $row;
+			}
+		}
+
+		$result->closeCursor();
+
+		return $calendarObjects;
+	}
+
 	/**
 	 * @param Component $comp
 	 * @return array