net-mpris

Control a remote D-Bus session as if it was running on the default D-Bus session bus on your machine. D-Bus only works on *nix systems, so this isn't going to work on Windows.

What it does?

Once you have everything correctly setup, you'll be able to control remote MPRIS supported media players (like mps-youtube, Spotify, etc.) as if that remote media player was running on your machine. The media player will show up and be controllable from your desktop environment's sound applet. Such as here we have an instance of mps-youtube playing some music on my Raspberry Pi and me able to control it via my main machine from my Cinnamon's default sound applet:

mps-youtube interfaces with MPRIS specification and allows for controls such as Play/Pause, Stop, Previous/Next track and Seeking. I can do all of these from my Cinnamon's sound applet.

One can also use multimedia keys on their keyboard (or set custom hotkeys) to control playback on the remote media player instance.

However, the Cinnamon sound applet and multimedia keys affects the volume levels at a system level and not via the MPRIS specification. So, changing the volume through this way will only change your local machine's volume levels and WILL NOT AFFECT the volume levels on the remote media player's instance!

Setting up D-Bus and net-mpris

You'll need to go through a series of steps before you can use net-mpris to do something like above.

Setting up the environment isn't so trivial. You'll need to make these arrangements before a machine can mimic a remote D-Bus session.

Server

On the main machine which will actually be running the media player (such as the Raspberry Pi in the example in above section), you'll need to install D-Bus:

$ sudo apt install dbus

Once installed, you'll need to modify your D-Bus session configuration file in /usr/share/dbus-1/session.conf so that D-Bus can bind to a TCP socket. This answer on stackoverflow tells you how to do that.

Next you'll need to set your DBUS_SESSION_BUS_ADDRESS environment variable telling media players to bind to this specific session bus. You can do this for the current terminal with:

$ eval $(dbus-launch --auto-syntax)

If you get this error when running the above command, where 55556 is the port number you set in your session.conf above:

dbus-daemon[2964]: Failed to start message bus: Failed to bind socket "*:55556": Address already in use

You'll need to kill the previous D-Bus session with:

$ fuser -k 55556/tcp

and then run the above command again and it shouldn't error this time.

You can now run any MPRIS supported media player from the same terminal such as:

$ spotify

or

$ mpsyt

and they are ready to be controlled from another machine via the TCP port you assigned in your D-Bus's session.conf!

Client

On the client machine (the one which will gain controls to the media player running on the server), you'll need to install playerctl (64-bit releases and Raspberry Pi releases) and dbus-python from PyPI:

$ pip3 install dbus-python

If dbus-python complains about installing a development version, download the tarball and run:

$ pip3 install -e .

in the extracted directory and it should now be installed ok.

Now, let's make sure everything is setup correctly so far.

Point the D-Bus session bus on your client machine to the one running on the server:

$ export DBUS_SESSION_BUS_ADDRESS='tcp:host=192.168.1.5,port=55556,family=ipv4

(Replace the IP address and port where D-Bus is listening on the host machine)

Now run:

$ playerctl -l

If this shows the name of the media player you ran on the host machine, like it does for me:

mps-youtube.instance15990

then everything is good to go!

$ git clone https://github.com/ritiek/net-mpris
$ cd net-mpris
$ python3 netmpris.py 192.168.1.5 -p 55556

and you should have the media player in your sound applet and should also be controllable from multimedia keys on your keyboard!

---

This initial setup may be cucumbersome but it isn't so bad the next time you wish to remote control MPRIS supported players. On the host machine, you would just need to prefix your MPRIS compatible media player command with dbus-launch:

$ dbus-launch <some-media-player-launch-command>

For example:

$ dbus-launch spotify

On the client machine, you could then run net-mpris with:

$ python3 netmpris.py <host-address> -p <dbus-port>

and everything should work correctly.

Alternate ways?

To be honest, I feel like I'm missing something out and that something like this should already be possible with some hacking on D-Bus itself. We probably don't need this code to act a middle man between the local and remotely running MPRIS controller. Anyway, I've yet to discover if something like that is possible. I'm up for all thoughts!

License

Since most of the code here is taken from mps-youtube which is GPLv3 licensed, it makes some sense to also keep this GPLv3 to avoid any potential conflicts.