fix(server): Allow negative rating (for rejected images)

[chkuendig]

Resolves (partially) #14454. ( edit: also, see relevant discord discussion)

XMP/Exif Metadata allows for negative ratings, with -1 meaning "rejected". See e.g. https://exiftool.org/TagNames/XMP.html#xmp:

Tag Name	Writable	Values / Notes
Rating	real	(a value from 0 to 5, or -1 for "rejected")

[danieldietzler]

Will negative ratings already be extracted? Are they stored correctly? The frontend also needs to handle them

[chkuendig]

Will negative ratings already be extracted? Are they stored correctly?

I missed a few things. Pushed it now to include all parts for extraction and storing. I tested this locally and it worked for me. Sorry for pushing the barebone commit yesterday.

The frontend also needs to handle them

I would add this as a separate part if possible. I don't even think these should necessarily be reflected in the ratings/star UI. Since it doesn't make much sense to show a negative star rating - maybe they should be flagged as isHidden instead? For now it would just be good to have the metadata in the file be represented in the database so users (me) can build processes around that (in my case I'll mark -1 as hidden and 5 as a favorite via the REST API).

[danieldietzler]

@chkuendig As long as you have checked that a rating of -1 does not actually break something on the clients I'm happy with doing that in the future PR :)

[danieldietzler]

Looks good! Thanks for also writing tests!

[chkuendig]

@chkuendig As long as you have checked that a rating of -1 does not actually break something on the clients

I tested web and iOS which handled this just fine (showing as no rating). Don't have Android available to test unfortunately.