Allow header returns the first route method it encounters

[ccrims0n]

Hi,

from starlette.routing import Route
from starlette.applications import Starlette
from starlette.responses import PlainTextResponse


def get_user(request):
    user_id = "John Doe"
    return PlainTextResponse('Hello, %s!' % user_id)

def edit_user(request):
    user_id = request.path_params['user_id']
    return PlainTextResponse('Edited user:, %s!' % user_id)

def delete_user(request):
    user_id = request.path_params['user_id']
    return PlainTextResponse('Deleted user:, %s!' % user_id)


routes = [
    Route('/user/{user_id}', get_user, methods=["GET"]),
    Route('/user/{user_id}', edit_user, methods=["PUT"]),
    Route('/user/{user_id}', delete_user, methods=["DELETE"])
]

app = Starlette(debug=True, routes=routes)

For the above application if I make a call to curl -X PATCH /user/123 -d "name=XYZ" it returns 405 status with Allow: GET header.
However, it should return 405 with Allow: GET, PUT, DELETE header.

Looks like the handle() is only returning the methods of the first route it encounters

if self.methods and scope["method"] not in self.methods:
    headers = {"Allow": ", ".join(self.methods)}
    if "app" in scope:
        raise HTTPException(status_code=405, headers=headers)
    else:
        response = PlainTextResponse("Method Not Allowed", status_code=405, headers=headers)
    await response(scope, receive, send)
else:
    await self.app(scope, receive, send)

It should search for all the matching routes and handle the Allow header accordingly.

[Kludex]

Seems valid.

[ccrims0n]

Route handler might not be the right place to handle this.
One way would be to handle it post route identification.
I will file a PR if you are okay with this.