Subsonic: Fix unhandled exception on deleteBookmark

There was an unhandled exception when the Subsonic action
`deleteBookmark` was called for a non-existent bookmark, and this got
logged as an error. This happened because, by convention, the business
layer modules should throw BusinessLayerException in case the requested
item doesn't exist. The SubsonicMiddleware catches such exceptions and
emits the proper Subsonic error response. But BookmarkBusinessLayer was
throwing wrong kind of exception here and it leaked through.

refs #1071

CHANGELOG.md

@@ -1,3 +1,13 @@
+## [Unreleased]
+
+### Added
+
+### Changed
+
+### Fixed
+- Subsonic: Unhandled exception when attempting to delete a non-existent bookmark
+  [#1071](https://github.com/owncloud/music/issues/1071)
+
 ## 1.8.4 - 2023-06-06
 ### Added
 - Support for Nextcloud 27 (tested on RC3)

lib/BusinessLayer/BookmarkBusinessLayer.php

@@ -9,12 +9,13 @@
  * @author Gavin E <no.emai@address.for.me>
  * @author Pauli Järvinen <pauli.jarvinen@gmail.com>
  * @copyright Gavin E 2020
- * @copyright Pauli Järvinen 2020, 2021
+ * @copyright Pauli Järvinen 2020 - 2023
  */
 
 namespace OCA\Music\BusinessLayer;
 
 use OCA\Music\AppFramework\BusinessLayer\BusinessLayer;
+use OCA\Music\AppFramework\BusinessLayer\BusinessLayerException;
 use OCA\Music\AppFramework\Core\Logger;
 
 use OCA\Music\Db\BookmarkMapper;
@@ -57,9 +58,13 @@ public function addOrUpdate(string $userId, int $type, int $entryId, int $positi
 
 	/**
 	 * @param int $type One of [Bookmark::TYPE_TRACK, Bookmark::TYPE_PODCAST_EPISODE]
-	 * @throws DoesNotExistException if such bookmark does not exist
+	 * @throws BusinessLayerException if such bookmark does not exist
 	 */
 	public function findByEntry(int $type, int $entryId, string $userId) : Bookmark {
-		return $this->mapper->findByEntry($type, $entryId, $userId);
+		try {
+			return $this->mapper->findByEntry($type, $entryId, $userId);
+		} catch (DoesNotExistException $ex) {
+			throw new BusinessLayerException($ex->getMessage());
+		}
 	}
 }