modify flask url before routing
I'd normalise the path before it gets to Flask, either by having the HTTP server that hosts the WSGI container or a proxy server that sits before your stack do this, or by using WSGI middleware.
The latter is easily written:
import refrom functools import partialclass PathNormaliser(object): _collapse_slashes = partial(re.compile(r'/+').sub, r'/') def __init__(self, application): self.application = application def __call__(self, env, start_response): env['PATH_INFO'] = self._collapse_slashes(env['PATH_INFO']) return self.application(env, start_response)You may want to log that you are applying this transformation, together with diagnostic information like the REMOTE_HOST and HTTP_USER_AGENT entries. Personally, I'd force that specific application to generate non-broken URLs as soon as possible.
Look at your WSGI server documentation to see how to add in extra WSGI middleware components.