Use MPRIS instead of proprietary spotify hooks

[draxaris1010]

When looking at pull request from librespot, I've seen someone is working on MPRIS support.
See pull request 1341 on librespot
MPRIS is a standard way on linux of letting other applications know and control (play/pause, skip/previous song) what music is playing.
This is done by sending the song title, artist and even location to thumbnail via D-Bus.
The specification of MPRIS can be found here: https://specifications.freedesktop.org/mpris-spec/latest/

[draxaris1010]

Also there is a library in go that implements MPRIS
https://pkg.go.dev/github.com/rmrobinson/go-mpris

[Topvennie]

Unfortunately I don’t see how implementing MPRIS would help us avoid using Spotify.

Currently, the librespot library uses a hook to send a POST request to SCC whenever a new song starts, including its Spotify ID. SCC then fetches additional information from Spotify, which currently includes:

• Track name
• Artists

In the rewrite branch, this expands to include:

• Track length
• Lyrics (coming soon)
• Genre (coming soon)

MPRIS doesn't provide all the data that SCC requires. As a result, a Spotify API request would still be necessary.

While alternative music sources could be used, it's worth mentioning that librespot is fundamentally a Spotify client library (and only for premium users). Therefore I think some additional requests won't hurt ;)