Flask: Blueprints with url_prefix responding in HTTP 308

[khera-shanu]

Expected Behavior

2xx response for an existing working URL

Actual Behavior

blueprints with url_prefix started to respond with 308 in the latest flask (used pip)

Environment

• Python version: Python 3.6.7
• Flask version: 1.0.3
• Werkzeug version: 0.15.4

[ThiefMaster]

Please provide a minimal piece of example code demonstrating this issue.

[khera-shanu]

read the issue, code won't be required.
I am getting this after latest version flask install, the whole application works on previous versions

[ThiefMaster]

Yes, code is required, because you seem to be the only one with this issue. Also, you didn't mention from which version you updated...

[khera-shanu]

https://github.com/khera-shanu/large/blob/master/app/views/user.py

this is the code

[ThiefMaster]

Again, please provide a MINIMAL example demonstrating your issue. That means, a single file/snippet one can run with flask run.

[XDfield]

same here.
@khera-shanu
try setting strict_slashes to False

app.url_map.strict_slashes = False

[saltaverde]

@khera-shanu I ran into this problem when refactoring all of my app's routes into separate Blueprint objects. There seems to be a difference in the defaults of Flask.route and Blueprint.route. The former worked as (I) expected with respect to trailing slashes in the url.

For example

app = Flask(__name__)

@app.route('/user')
def user():
    . . .

would work the same whether the request was to /user or /user/.

However, in order to make a Blueprint behave this way, I had to add strict_slashes=False to each of the Blueprint.route calls.

For example

bp = Blueprint('user', __name__, url_prefix='/user')

@bp.route('/', strict_slashes=False)
def user():
    . . .

[qihboy]

same issue found, and app.url_map.strict_slashes = False not worked for us.

We found if blueprint.route registered route for sub modules, like /api/module1/ for app/module/entrance.py and defined route like route = ['/', ''] in entrance.py,
when request accepted, it will return a 308 response and then a 200 response, some clients like web browser will handle this, some others will not(such like another web service).

We fixed this by redefine route for this situation:route = '/callbak', and now it's working for good.

[hugadams]

For anyone coming from google, I got this error when one of my routes had a trailing slash eg.

@app.route("/foo/")

instead of

@app.route("/foo")

[petrem]

Again, for googlers:

This is because of the strict_slahes setting (default True, see https://werkzeug.palletsprojects.com/en/1.0.x/routing/#maps-rules-and-adapters) and this change in Werkzeug:

https://github.com/pallets/werkzeug/pull/1342