feat(preview): Expire previews

Signed-off-by: provokateurin <kate@provokateurin.de>

Author: provokateurin

config/config.sample.php

@@ -2917,4 +2917,12 @@
 		'fe80::/10',
 		'10.0.0.1',
 	],
+
+	/**
+	 * Delete previews older than a certain number of days to reduce storage usage.
+	 * Less than one day is not allowed, so set it to 0 to disable the deletion.
+	 *
+	 * Defaults to ``0``.
+	 */
+	'preview_expiration_days' => 0,
 ];

core/BackgroundJobs/ExpirePreviewsJob.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+namespace OC\Core\BackgroundJobs;
+
+use OC\Preview\PreviewService;
+use OCP\AppFramework\Utility\ITimeFactory;
+use OCP\BackgroundJob\IJob;
+use OCP\BackgroundJob\TimedJob;
+use OCP\IConfig;
+
+class ExpirePreviewsJob extends TimedJob {
+	public function __construct(
+		ITimeFactory $time,
+		private readonly IConfig $config,
+		private readonly PreviewService $service,
+	) {
+		parent::__construct($time);
+
+		$this->setTimeSensitivity(IJob::TIME_INSENSITIVE);
+		$this->setInterval(60 * 60 * 24);
+	}
+
+	protected function run($argument): void {
+		$days = $this->config->getSystemValueInt('preview_expiration_days');
+		if ($days <= 0) {
+			return;
+		}
+
+		$this->service->deleteExpiredPreviews($days);
+	}
+}

lib/composer/composer/autoload_classmap.php

@@ -1305,6 +1305,7 @@
     'OC\\Core\\BackgroundJobs\\BackgroundCleanupUpdaterBackupsJob' => $baseDir . '/core/BackgroundJobs/BackgroundCleanupUpdaterBackupsJob.php',
     'OC\\Core\\BackgroundJobs\\CheckForUserCertificates' => $baseDir . '/core/BackgroundJobs/CheckForUserCertificates.php',
     'OC\\Core\\BackgroundJobs\\CleanupLoginFlowV2' => $baseDir . '/core/BackgroundJobs/CleanupLoginFlowV2.php',
+    'OC\\Core\\BackgroundJobs\\ExpirePreviewsJob' => $baseDir . '/core/BackgroundJobs/ExpirePreviewsJob.php',
     'OC\\Core\\BackgroundJobs\\GenerateMetadataJob' => $baseDir . '/core/BackgroundJobs/GenerateMetadataJob.php',
     'OC\\Core\\BackgroundJobs\\LookupServerSendCheckBackgroundJob' => $baseDir . '/core/BackgroundJobs/LookupServerSendCheckBackgroundJob.php',
     'OC\\Core\\BackgroundJobs\\PreviewMigrationJob' => $baseDir . '/core/BackgroundJobs/PreviewMigrationJob.php',

lib/composer/composer/autoload_static.php

@@ -1346,6 +1346,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OC\\Core\\BackgroundJobs\\BackgroundCleanupUpdaterBackupsJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/BackgroundCleanupUpdaterBackupsJob.php',
         'OC\\Core\\BackgroundJobs\\CheckForUserCertificates' => __DIR__ . '/../../..' . '/core/BackgroundJobs/CheckForUserCertificates.php',
         'OC\\Core\\BackgroundJobs\\CleanupLoginFlowV2' => __DIR__ . '/../../..' . '/core/BackgroundJobs/CleanupLoginFlowV2.php',
+        'OC\\Core\\BackgroundJobs\\ExpirePreviewsJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/ExpirePreviewsJob.php',
         'OC\\Core\\BackgroundJobs\\GenerateMetadataJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/GenerateMetadataJob.php',
         'OC\\Core\\BackgroundJobs\\LookupServerSendCheckBackgroundJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/LookupServerSendCheckBackgroundJob.php',
         'OC\\Core\\BackgroundJobs\\PreviewMigrationJob' => __DIR__ . '/../../..' . '/core/BackgroundJobs/PreviewMigrationJob.php',

lib/private/Preview/Db/PreviewMapper.php

@@ -9,6 +9,8 @@
 
 namespace OC\Preview\Db;
 
+use DateInterval;
+use DateTimeImmutable;
 use OCP\AppFramework\Db\Entity;
 use OCP\AppFramework\Db\QBMapper;
 use OCP\DB\Exception;
@@ -26,6 +28,7 @@ class PreviewMapper extends QBMapper {
 	private const TABLE_NAME = 'previews';
 	private const LOCATION_TABLE_NAME = 'preview_locations';
 	private const VERSION_TABLE_NAME = 'preview_versions';
+	public const MAX_CHUNK_SIZE = 1000;
 
 	public function __construct(
 		IDBConnection $db,
@@ -199,11 +202,16 @@ public function getLocationId(string $bucket, string $objectStore): string {
 	/**
 	 * @return \Generator<Preview>
 	 */
-	public function getPreviews(int $lastId, int $limit = 1000): \Generator {
+	public function getPreviews(int $lastId, int $limit = self::MAX_CHUNK_SIZE, ?int $maxAgeDays = null): \Generator {
 		$qb = $this->db->getQueryBuilder();
 		$this->joinLocation($qb)
 			->where($qb->expr()->gt('p.id', $qb->createNamedParameter($lastId, IQueryBuilder::PARAM_INT)))
 			->setMaxResults($limit);
+
+		if ($maxAgeDays !== null) {
+			$qb->andWhere($qb->expr()->lt('mtime', $qb->createNamedParameter((new DateTimeImmutable())->sub(new DateInterval('P' . $maxAgeDays . 'D'))->getTimestamp(), IQueryBuilder::PARAM_INT)));
+		}
+
 		return $this->yieldEntities($qb);
 
 	}

lib/private/Preview/PreviewService.php

@@ -112,7 +112,7 @@ public function getPreviewsForMimeTypes(array $mimeTypes): \Generator {
 	public function deleteAll(): void {
 		$lastId = 0;
 		while (true) {
-			$previews = $this->previewMapper->getPreviews($lastId, 1000);
+			$previews = $this->previewMapper->getPreviews($lastId, PreviewMapper::MAX_CHUNK_SIZE);
 			$i = 0;
 
 			// FIXME: Should we use transaction here? Du to the I/O created when
@@ -124,7 +124,7 @@ public function deleteAll(): void {
 				$lastId = $preview->getId();
 			}
 
-			if ($i !== 1000) {
+			if ($i !== PreviewMapper::MAX_CHUNK_SIZE) {
 				break;
 			}
 		}
@@ -137,4 +137,33 @@ public function deleteAll(): void {
 	public function getAvailablePreviews(array $fileIds): array {
 		return $this->previewMapper->getAvailablePreviews($fileIds);
 	}
+
+	public function deleteExpiredPreviews(int $maxAgeDays): void {
+		try {
+			$this->connection->beginTransaction();
+
+			$lastId = 0;
+			$startTime = time();
+			while (true) {
+				$previews = $this->previewMapper->getPreviews($lastId, PreviewMapper::MAX_CHUNK_SIZE, $maxAgeDays);
+				$i = 0;
+				foreach ($previews as $preview) {
+					$this->deletePreview($preview);
+					$i++;
+					$lastId = $preview->getId();
+				}
+
+				if ($i !== PreviewMapper::MAX_CHUNK_SIZE) {
+					break;
+				}
+
+				// Stop if execution time is more than one hour.
+				if (time() - $startTime > 3600) {
+					return;
+				}
+			}
+		} finally {
+			$this->connection->commit();
+		}
+	}
 }

lib/private/Setup.php

@@ -14,6 +14,7 @@
 use InvalidArgumentException;
 use OC\Authentication\Token\PublicKeyTokenProvider;
 use OC\Authentication\Token\TokenCleanupJob;
+use OC\Core\BackgroundJobs\ExpirePreviewsJob;
 use OC\Core\BackgroundJobs\GenerateMetadataJob;
 use OC\Core\BackgroundJobs\PreviewMigrationJob;
 use OC\Log\Rotate;
@@ -518,6 +519,7 @@ public static function installBackgroundJobs(): void {
 		$jobList->add(CleanupDeletedUsers::class);
 		$jobList->add(GenerateMetadataJob::class);
 		$jobList->add(PreviewMigrationJob::class);
+		$jobList->add(ExpirePreviewsJob::class);
 	}
 
 	/**