[v1.2] Support pluggable webhook server backend (aiohttp / Flask / FastAPI / Express)

[MaxMansfield]

Context

The SDK currently bundles its own webhook HTTP server (http.server.BaseHTTPRequestHandler in Python; stock Node http module in Node.js). Apps that already use aiohttp / Flask / FastAPI / Express / Lambda have to choose:

• Run TWO HTTP servers in the same process (the SDK's + their own), or
• Abandon @rtms.on_webhook_event and reimplement webhook routing themselves

Neither is acceptable for production deployments at scale. SQS-replay failover (the canonical production pattern) specifically needs the webhook ingest layer to be Lambda or aiohttp, decoupled from the RTMS client lifecycle.

What to ship

Opt-in factory pattern. App provides its own HTTP router; the SDK exposes a callable that the app mounts at the webhook path:

# Python — FastAPI integration example
from fastapi import FastAPI, Request
app = FastAPI()

handler = rtms.webhook_handler(on_event=my_callback)

@app.post("/webhook")
async def webhook(request: Request):
    payload = await request.json()
    return await handler(payload, request.headers)

// Node.js — Express integration example
const handler = rtms.webhookHandler({ onEvent: myCallback });
app.post("/webhook", express.json(), (req, res) => handler(req.body, req.headers, res));

The existing @rtms.on_webhook_event + rtms.run() path stays for the simple/quickstart case. The factory is the production path.

Acceptance criteria

• Python: rtms.webhook_handler(...) returns an async callable
• Node.js: rtms.webhookHandler(...) returns a request handler compatible with Express middleware shape
• FastAPI, aiohttp, Flask integration samples in examples/python.md
• Express integration sample in examples/node.md
• Existing @rtms.on_webhook_event quickstart path continues to work unchanged

Cross-language parity

• Same constructor parameter names where idiomatic
• Same callback signature (payload, headers/request, response)
• Both ship in the same release
• PR description includes "Cross-language parity check" section

Source

Tracked in vault: Projects/RTMS SDK v1.2.md → DEVS-X6.

Tracker

Part of the v1.2 milestone. Project: https://github.com/orgs/zoom/projects/11.