Path matching with URLs ending in //

[h3kker]

I can't seem to get flask to match URLs ending in double slashes. I have a client app (that I don't control) that under some circumstances sends requests like this: /v1/collections//

Expected Behavior

Output "found double"

from flask import Flask
app = Flask(__name__)

@app.route('/test//')
def double(other):
    return 'found double'

Actual Behavior

curl localhost:5000/test//
# 404 not found

I have also tried with paths:

@app.route('/test/<path:other>')
def double(other):
    return 'found double'

but no luck either.

Environment

$ flask --version
Python 3.7.4
Flask 1.1.1
Werkzeug 0.16.0

[bolivierjr]

I can't seem to find a way, even with a catch-all, to hit a double slashed ended uri. Seems like you typically need a rewrite rule to get rid of the trailing slashes. One solution would be to put an nginx reverse proxy in front of the flask app with a rewrite in the config. e.g. rewrite ^/test/(.*)$ /$1 break; or ^test(/.*)$

[h3kker]

Wouldn't you consider this a bug? After all I want my route to match a certain pattern and something is preventing that. At the least I think it is unexpected behaviour.

Especially since internal double slashes work (@app.route('/test//hase'))

Rewriting in an upstream proxy is some pain. Then my development environment behaves differently and I cannot unit-test those particular routes.

If there's really no way to match that, can I somehow rewrite the URL in flask before the path matching happens?

Thanks,
Heinz

[qdzzyb2014]

try this

from flask import Flask
from werkzeug.routing import PathConverter

app = Flask(__name__)


class EverythingConverter(PathConverter):
    regex = '.*?'


app.url_map.converters['everything'] = EverythingConverter


@app.route('/test/<everything:other>')
def double(other):
    print(f'other: {other}')
    return 'found double'

https://stackoverflow.com/questions/24000729/flask-route-using-path-with-leading-slash

[davidism]

We just added a merge_slashes feature that merges consecutive slashes in URLs and redirects to the canonical location. I've extended that to include trailing slashes.

You still might have issues that Werkzeug can't address. Consecutive slashes in URLs aren't usually correct, and you should open a bug report against the client producing those URLs. Since merge_slashes issues a redirect rather than silently matching, the client will still need to be good enough to follow redirects when making requests. Many HTTP servers will merge slashes before they even get to the application, so you will probably not see this issue in production anyway.