matrix-macOS-Message-bridge

A Matrix macOS Messages puppeting bridge.

Prior Art

Bridges

• mautrix-imessage - Multi-purpose bridge for:
  • macOS
  • macOS without SIP (deprecated due to Barcelona deprecation)
  • iOS (deprecated)
  • Android (deprecated in favor of mautrix-gmessages)
• beeper-imessage - Deprecated/Archived

NSAttributedString

Kinda crazy we're still stuck with stuff from NextStep

Primary implementation of decoding NSAttributedString/typedstream/streamtyped from ReagentX/immessage-exporter and further documented in an extensive write-up here

Other implementations:

• python-typedstream (partial implementation, but probably workable)
• BlueBubbles/node-typedstream (probably entirely workable since they're doing what we're doing)
• meowUnsafeDecodeAttributedString from mautrix-imessage (calls out to ObjectiveC and throws away a lot of data in the macOS code path)
• yakuter/nsattrparser (surface level string grab)

Architectural Decisions

The three main reasons for this bridge were:

1. All but one existing bridge is deprecated
2. The single operable bridge (mautrix-imessage in macOS mode) has some sharp edges
3. mautrix-imessage could be upgraded to the shiny "new" bridgev2

With that in mind, the intention is to create a bare-minimum replacement for mautrix-imessage's macOS bridge using bridgev2 and attempt to remove these sharp edges:

1. Easier installation as either a LaunchAgent or LaunchDaemon (Daemon may be impossible due to permissions issues)
2. Improve bridge startup robustness by addressing or surfacing issues:
   1. Detect if Messages needs to be launched or restarted
   2. Attempt to ensure TCC (Transparency, Consent and Control) dialogs pops up if required by making the bridge a full-blown macOS application if needed
   3. Check all external dependencies work before starting
3. Replace brittle Contacts support if possible
4. Attempt to remove requirement for Full Disk Access

Documentation

TODO: Document building and running the bridge as a process and as a LaunchAgent.