FastAPI route discovery broken: fastapi.routing.request_response not patched

[bora-humace]

Description

Aikido Zen v1.2.32 patches starlette.routing.request_response for route discovery (post_response hook), but FastAPI defines its own request_response in fastapi/routing.py (line 97). APIRoute.__init__ uses the FastAPI copy, not Starlette's.

This means pre_response and post_response hooks never fire for FastAPI API endpoints — route discovery, API spec generation, and per-route IP blocking are silently skipped.

Evidence

import aikido_zen
aikido_zen.protect()

import starlette.routing
import fastapi.routing

print(hasattr(starlette.routing.request_response, '__wrapped__'))  # True ✅
print(hasattr(fastapi.routing.request_response, '__wrapped__'))    # False ❌

Only docs endpoints (/openapi.json, /docs, /redoc) that use starlette.routing.Route directly get the wrapper applied. All @app.get/@app.post endpoints using APIRoute are unpatched.

SYNC_DATA consistently shows current_routes: {} even with active API traffic.

Root Cause

FastAPI's fastapi/routing.py defines its own request_response function (copy of Starlette's with AsyncExitStack additions), rather than importing from starlette.routing. Aikido's @on_import("starlette.routing") hook only patches the Starlette module.

The Fix I Applied (Works in Production)

After protect(), patch FastAPI's copy with the same wrapper:

import fastapi.routing
from aikido_zen.sources.starlette.starlette_routing import _request_response
from aikido_zen.sinks import patch_function

patch_function(fastapi.routing, "request_response", _request_response)

After deploying this to production, all FastAPI endpoints are discovered correctly with auto-generated API specs, query parameter detection, and auth scheme detection. Route discovery, user tracking, and middleware integration all work as expected.

The same approach should be added natively via a @on_import("fastapi.routing", "fastapi") hook.

Environment

• aikido-zen: 1.2.32
• fastapi: 0.135.2
• starlette: 1.0.0
• Python: 3.13