matrx-connect 0.1.4

FastAPI middleware, auth, streaming infrastructure, and context management for the Matrx ecosystem

matrx-connect

FastAPI connectivity layer for the Matrx ecosystem: auth middleware, streaming-response infrastructure, request-scoped AppContext, and the Emitter protocol. Despite the name, "connect" is about connecting a FastAPI app to the Matrx streaming + auth contract — not database connectivity.

Install

pip install matrx-connect

Python 3.12+ required. Depends only on matrx-utils from the Matrx family.

What's in the box

Module	What it does
matrx_connect.context.app_context	AppContext dataclass + ContextVar + get_app_context / set_app_context / try_get_app_context / clear_app_context
matrx_connect.context.emitter_protocol	Emitter protocol — every method any producer can call (send_chunk, send_reasoning, send_phase, send_data, send_info, send_warning, fatal_error, send_end, tool events, …)
matrx_connect.context.events	Pydantic event payload schemas shared with the frontend
matrx_connect.emitters.stream_emitter	StreamEmitter — the JSONL/NDJSON HTTP streaming implementation
matrx_connect.emitters.console_emitter	ConsoleEmitter — dev/test implementation that prints to stdout
matrx_connect.middleware.auth	AuthMiddleware — pluggable JWT + admin-token + fingerprint resolution, with a resolve_guest callback hook
matrx_connect.streaming.response	create_streaming_response(ctx, task, *args, ...) — the ONLY public entry point for streaming endpoints
matrx_connect.dependencies	context_dep — the FastAPI Depends() helper that pulls AppContext into a route handler

The streaming endpoint pattern

Every streaming route follows this exact shape. It's enforced across every repo that uses matrx-connect, so that the behavior of heartbeats, client disconnects, and error handling stays consistent:

from fastapi import APIRouter, Depends
from matrx_connect import AppContext, context_dep
from matrx_connect.streaming import create_streaming_response

router = APIRouter()

@router.post("/topics/{topic_id}/search")
async def trigger_search(topic_id: str, ctx: AppContext = Depends(context_dep)):
    return create_streaming_response(
        ctx, _run_search, topic_id,
        initial_message="Starting search…", debug_label="ResearchSearch",
    )

async def _run_search(emitter, topic_id: str):
    # AppContext is already set on the ContextVar.
    # Cancellation + exception handling are done for you.
    result = await do_work(topic_id)
    await emitter.send_data(SearchResult(...).model_dump())
    await emitter.send_end()

What create_streaming_response does for you:

• Creates the StreamEmitter, attaches it to AppContext, and pushes AppContext onto the ContextVar.
• Spawns the task as a background asyncio.Task.
• Catches CancelledError (client disconnect) and generic exceptions — the latter are surfaced via emitter.fatal_error(...).
• Emits heartbeat keepalives while the task is running.
• Clears the ContextVar on exit.

Your task function never touches set_app_context / clear_app_context / CancelledError. If you find yourself reaching for those symbols in application code, extend create_streaming_response instead.

Wiring the auth middleware

from fastapi import FastAPI
from matrx_connect.middleware.auth import AuthMiddleware

app = FastAPI()
app.add_middleware(
    AuthMiddleware,
    jwt_secret=settings.JWT_SECRET,
    admin_token=settings.ADMIN_TOKEN,
    admin_user_id=settings.ADMIN_USER_ID,
    resolve_guest=my_guest_resolver,   # optional callback for fingerprint-based guests
)

After this, every request has an AppContext on request.state.context and context_dep will hand it to any route handler that depends on it.

Standalone-friendliness

matrx-connect has a single sibling dependency (matrx-utils, for verbose-logging). It assumes no ORM, no database, no Supabase — wire those in from your app. The Emitter is a typing.Protocol, so you can hand create_streaming_response any object that satisfies the shape.

Contributing

See CLAUDE.md for package-specific import rules and conventions. This package lives in the aidream monorepo at github.com/AI-Matrix-Engine/aidream-current.

License

MIT.