Errors logged when Subsonic getCoverArt called with invalid parameter

[paulijar]

Apparently, DSub calls the Subsonic API getCoverArt with an invalid argument id=null in some situation. When this happens, an error like the one shown below gets logged to nextcloud.log, at least on NC28. The Music app handles this otherwise gracefully by returning a specification-compliant error message to the client.

{“reqId”:“ZFg1CZwfjN3RaSBn45mF”,“level”:3,“time”:“2024-04-02T19:27:09+00:00”,“remoteAddr”:“172.xx.xxx.1”,“user”:“–”,“app”:“PHP”,“method”:“GET”,“url”:“/apps/music/subsonic/rest/getCoverArt.view?u=user&p=enc:XXXXXXXXXXXXXXX&v=1.2.0&c=DSub&id=null”,“message”:“Undefined array key "" at /var/www/nc/lib/private/AppFramework/Http.php#128”,“userAgent”:“DSub”,“version”:“28.0.4.1”,“data”:{“app”:“PHP”},“id”:“660e5c024275a”}

The invalid call could maybe be logged on the warning or info or debug level but not on the error level. And definitely, the log should then be something explaining the actual problem rather than about undefined array key somewhere within the NC framework.

It should be checked also if the same problem is present on the other cases where the Subsonic API returns some error response.

First reported here: https://help.nextcloud.com/t/get-a-lot-of-errors/27300/4

[paulijar]

Closing in favor of the more generic case #1142.