Rethink `tracker3 tags`
Tagging in Tracker 2:
tracker tagcommand to apply, delete and show tags
- Stored as
<file://home/sam/Photos/MyPhoto.jpg> nao:hasTag <urn:tag:Holiday>using nao:hasTag attribute
- Stored with all other cached and app-specific data in ~/.cache/tracker`, accessible by any app
- Tags extracted from EXIM metadata in photos and PDF metadata in documents stored in the same way
- No GNOME app actually displayed tag data as of last Tracker 2.x release (~2020)
- In 2017 Nautilus explicitly decided against custom tags in favour of separate 'starred files' feature
Tagging in Tracker 3, as of July 2021:
- Data sandboxing and multiple databases is now a thing.
- Tags extracted from photos & documuments stored in tracker-miner-fs-3 database, as before
tracker3 tagsreads and writes nao:hasTag in tracker-miner-fs-3 database
- unless run inside a sandbox, in which case it can only read
- this is a violation of the principal that user-created and cached data is kept separate. How do you back up your tags?
If shared user-generated tags is a goal, we should provide a separate
tracker-tags-3 database where apps can store a shared set of user-created tags. It's not clear if there's any demand for this among app developers or users, though.