Discord Music Presence

A few years ago, I switched off of Spotify because I was less than impressed with their endorsement of Joe Rogan. I went with TIDAL for their lack of being Spotify, and I’ve been happy with their service (and lack of Joe Rogan) ever since. However, I’ve been missing one thing from my Spotify days: Discord presence.

Discord’s Spotify integration is super custom and impossible to replicate without partnering directly with TIDAL. However, we can get fairly close with Discord’s RPC server. RPC is a bit of a well-known secret in the community; although it’s marked as “private beta” in the documentation, the documentation actually only covers the WebSocket transport (which is indeed in private beta and inaccessible to most apps). However, there’s a secret third second option that uses IPC as the transport layer, and this transport layer is totally open for any app to use but remains (as-yet) undocumented. There are some subtle differences in functionality, but it’s perfectly adequate for the simple task of setting presence activity.

Connecting to Discord

Many years ago, devsnek wrote the discord-rpc client library which served as a reasonable reference implementation for my purposes. The protocol is super simple: the first 4 bytes represent the op code, the next 4 bytes represent the length of the payload, and the remaining bytes are the payload in JSON format (my implementation). This protocol applies bidirectionally.

Negotating with the client is also not super complicated, and the official RPC docs are actually super useful for this because it works the same way. After requesting to authorize, the user is redirected to their Discord app where they can choose to allow the app to access their account. The app then goes through the regular OAuth2 flow to exchange the code with a regular access token. At this point, we’re fully connected to the Discord app and can perform most RPC operations. Specifically, we’re concerned about the SET_ACTIVITY command, which will let our application set the user’s activity.

Connecting to Music

Although my primary goal was getting playback information out of TIDAL, they do not expose any API which allows this. Ironically, they provide an SDK dedicated to making an entire custom TIDAL player but they have no way of interacting with their own player. I was uninterested in re-implementing TIDAL, so I began digging for alternatives.

musicpresence.app is the leading solution which does this today. I nearly ended my search here, since it does exactly what I want out of the box. However, it’s closed source and I was still interested in trying to solve this problem anyway.

Although I didn’t use it directly, Music Presence did give me a line on pulling playback information directly from the operating system (something I’d completely forgotten about). Since my personal machine is Windows, I got cracking and had a working solution up very quickly. Although the Windows API is relatively confusing and not without its quirks, the Windows Rust SDK is very good and it’s trivial to access this information with just a few syscalls.

MacOS

However, my work machine is a Mac and macOS is notorious for locking things down. Music playback information is no exception and, at the time I was writing the initial version of this app, it was only available via the reverse engineered MediaRemote framework. It took me a bit longer to get something working on macOS since directly calling Objective C functions is a bit more complex than using the pre-built Windows crate, but I did eventually get the app linked to the MediaRemote framework and pulling data from it.

I figured I was done; I had a simple app that worked on both Windows and macOS. However, my success was short-lived: with the release of macOS 15.4, Apple did what Apple does best and ruined the fun by making the MediaRemote framework fully private¹, only accessible by internal approved applications.

I gave up, figuring that the effort of getting this working on macOS would be too great. While having something on Windows would be useful, I actually spend most of my listening time on macOS and it wouldn’t be super helpful.

Perl to the Rescue

Months passed and my curiosity got the better of me. Chatting about the issues I’d been having, I was pointed towards ungive/mediaremote-adapter (authored by the same person building Music Presence) and noticed that they’d solved the macOS issue.

This works by using a system binary – /usr/bin/perl in this case – which is entitled to use the MediaRemote framework and by dynamically loading a custom helper framework that prints real-time updates to stdout.

It’s fairly cursed, but it’s a fully functional solution for getting media playback information from macOS.

Reinspired, I picked up the project again and finally finished a robust solution for both macOS and Windows. My solution is open sourced on GitHub, although it certainly wouldn’t be possible without the legends that came before: shoutout to ungive for such a creative solution to pulling playback information from macOS.