Stop propogation of request to next middleware if response returned from first middleware in FastApi - fastapi

Question

I am working on a problem where in I am creating a middleware that responds to one api and if that api is different then we go to next middleware else we exit out from the first middleware.
Maybe I have not understood how middleware works in FastApi but my code is not working so any assistance will be welcomed.
My code is as below
#app.middleware("http")
async def verify_user_agent(request: Request, call_next):
if request.url.path == "/something" and request.method == "GET":
return JSONResponse(content={"Something": True}, status_code=200)
else:
await call_next(request)
return JSONResponse(content={
"message": "redirecting to api middleware"
}, status_code=307)
# This middleware should be hit only if route is not /something
#app.middleware("http")
async def api_route(request: Request, call_back):
if request.url.path == "/api":
return JSONResponse(content={"api": True}, status_code=200)
return JSONResponse(content={"api": False})
Here even if the first route called is /something still the second middleware is called even though the response is already sent by the first middleware
If you need any more information then please do lemme know

Answer 1

So I think you have understood middleware just fine, however there is just one thing you are missing and that is in relation to the precedence of your middleware. Precedence can be determined by the order of your middleware and FastApi will register your middleware in the reverse order that they are defined in. This means in your example the first middleware in line is the one that checks for the /api route, which means it never gets to the /something check. all you need to do is swap them around.
# This middleware will be called second
#app.middleware("http")
async def api_route(request: Request, call_back):
if request.url.path == "/api":
return JSONResponse(content={"api": True}, status_code=200)
return JSONResponse(content={"api": False})
# this middleware will be called first
#app.middleware("http")
async def verify_user_agent(request: Request, call_next):
if request.url.path == "/something" and request.method == "GET":
return JSONResponse(content={"Something": True}, status_code=200)
else:
await call_next(request)
return JSONResponse(content={
"message": "redirecting to api middleware"
}, status_code=307)