Routes with trailing slash do not work under default API Options

Hello,

It seems when using the current default for api.req_options.strip_url_path_trailing_slash which is False, adding a slash at the end of a route doesn’t work.

I think I found out what the problem is.

Here is the code I tried:

import falcon

class StaticResource(object):

    def on_get(self, _: falcon.Request, resp: falcon.Response) -> None:
        resp.status = falcon.HTTP_200
        resp.content_type = 'text/plain'
        resp.body = 'static'

def create_app() -> falcon.API:
    api = falcon.API()
    api.req_options.strip_url_path_trailing_slash = False
    api.add_route('/static_route/', StaticResource())
    api.add_route('/static_route2', StaticResource())
    print(api._router._finder_src)
    return api

The finder_src compiled function is :

def find(path, return_values, patterns, converters, params):
    path_len = len(path)
    if path_len > 0:
        if path[0] == 'static_route':
            if path_len == 1:
                return return_values[0]
            return None
        if path[0] == 'static_route2':
            if path_len == 1:
                return return_values[1]
            return None
        return None
    return None

We see that the code generated for both routes is the same. The path passed to this function when calling uri: “http://127.0.0.1:8000/static_route/” is : [‘static_route’, ‘’] which has a length of 2, leading the function to return None and therefore an HTTPError 404. When calling uri: “http://127.0.0.1:8000/static_route”, the function returns the correct route and leads to HTTP 200.

Therefore using the default option leads to an impossibility to have routes ending with a trailing slash and even worse, when using routes ending with a trailing slash, the route without it works…

[vishalrp]

Hello, we experienced this issue as well. We were on version 1.4.1 and one of the routes was defined with a / in the end. It used to work with and without the slash when queried. However, after upgrading, querying with a / returns a 404.

[nZac]

Hi @laurent-chriqui, thanks for submitting a bug report, we really appreciate when it includes code!

I am not sure I understand what you expect. Note that, req_options.strip_url_path_trailing_slash controls how the Request segments are determined, not how routing works, they are independent ideas.

Consider a route add_route('/home/', HomeResc()) and add_route('/home/{param}, Dashboard()).

How would you route a request to /home/data vs /home/ with strip_url_path_trailing_slash=False? Should /home/ go to HomeResc or should it go Dashboard? I think there is an argument it should go to Dashboard with param="" and that is what it does. Here is a quick example:

import falcon
import falcon.testing
import falcon.routing


class TestResource:
    def on_get(self, req, resp, **kwargs):
        resp.media = {'params': kwargs}


api = falcon.API()
api.add_route('/home/', TestResource())
api.add_route('/home/{id}', TestResource())

client = falcon.testing.TestClient(api)

api.req_options.strip_url_path_trailing_slash = False
assert client.simulate_get('/home').json['params'] == {}
assert client.simulate_get('/home/').json['params'] == {'id': ''}
assert client.simulate_get('/home/data').json['params'] == {'id': 'data'}

This changes slightly with strip_url_path_trailing_slash=True:

# ... same as above

api.req_options.strip_url_path_trailing_slash = True
assert client.simulate_get('/home').json['params'] == {}
assert client.simulate_get('/home/').json['params'] == {}.  # Note, we don't get `id`
assert client.simulate_get('/home/data').json['params'] == {'id': 'data'}

This might point to us needing to raise when there is a trailing slash passed to add_route since it is ultimately meaningless.

Morale of the story strip_url_path_trailing_slash is about the Request handling not about the routers behavior.

I am going to mark this as needing documentation here. If the other maintainers think there are code level changes for this… or if I am patently wrong (that happens far more often than I like!) please let me know!

Bonus… if you would like it to be different you can change it! 🎉

Bonus 2… If you are actually trying to serve statics, you might want to look at add_static_route. If it doesn’t meet your needs, let us know, we might be able to add features!

Bonus 3… Thanks again for submitting this!