Get path template URL in middleware

[dan-cbm]

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Example Code

class HTTPMiddleware(BaseHTTPMiddleware):
    def __init__(self, app):
        super().__init__(app)

    async def dispatch(self, request: Request, call_next):
        response = await call_next(request)
        # print path like  /api/example/1234/cheese/567/info
        logger.info(f"Received {request.method} on {request.url.path}")

        # TODO: print path as well like  /api/example/{company_id}/cheese/{site_id}/info 
        return response

Description

I'm working on some FastAPI middlewear which we use for logging all of our API requests. At present I'm logging the request path, but I'd like to also log the template URL for the endpoint e.g. the literal string /api/example/{company_id}/cheese/{site_id}/info so that we can later filter our logs and see all request to a given endpoint, regardless of the particular IDs in the url.

Is this possible with FastAPI? Somehow Sentry is able to tag errors with the endpoint URL in the "template form" we want, but I can't figure out how to access that information myself.

Operating System

Linux

Operating System Details

No response

FastAPI Version

0.104.1

Pydantic Version

2.6.1

Python Version

3.11.10

Additional Context

No response

[luzzodev]

The routing phase will inject route info in request, so you can can access to those information after you received your response.

In your case:

class HTTPMiddleware(BaseHTTPMiddleware):
    def __init__(self, app):
        super().__init__(app)

    async def dispatch(self, request: Request, call_next):
        response = await call_next(request)
        # print path like  /api/example/1234/cheese/567/info
        print(f"Received {request.method} on {request.url.path}")

        # TODO: print path as well like  /api/example/{company_id}/cheese/{site_id}/info
        print(request.scope["route"].path)
        return response

Just be careful that if a response fails, exceptions are not handled, or the routing phase is never reached due to an error, then the routing information will not be injected. Always check if the route key exists.