Any way to adjust volume/control playback programatically (ie, from command line)?

[YutongGu]

Is your feature request related to a problem? Please describe.
I'm running librespot on a raspberry pi and I'd like to be able to adjust the volume and control playback of my librespot instance using gpio button inputs and have the new volume or new track reflect in the app. I'm using a pipe backend so I can't use alsa to adjust the volume. This is a intentional design choice so I'd prefer not to have to switch to alsa.

Describe the solution you'd like
I'd like for there to be some kind of DBus interface or even a simple web socket that I can connect to in order to read and write volume and playback commands to librespot

Describe alternatives you've considered
I've considered alsa but as mentioned before, I would prefer to stick to the pipe backend. I also doubt using alsa will satisfy the requirement that the new volume reflect in the spotify app or solve for the ability to pause/play/skip.

Additional context
None

[photovoltex]

The only way to currently influence the volume, is via the startup parameter to adjust the starting volume.

I think #1341 is what you are looking for, but it seems quite stale currently.

[roderickvd]

You may find #1341 interesting.

[photovoltex]

If you want a solution right now, spotifyd might be worth a look :)

[YutongGu]

Ooh nice! I didn't know about spotifyd. What's main the difference between that and librespot?

[photovoltex]

It's pretty much just librespot but with more functionality built around the library. I also just know that it exists with more functionality under linux, but can't point to anything specific as I never deep dive into the project yet.