Flask redirecting multiple routes

debugging routes:

Update: to address the primary question "what's wrong with my routes", the simplest way to debug that is to use app.url_map; e.g:

>>> app.url_mapMap([<Rule '/user/<id>/<username>/' (HEAD, OPTIONS, GET) -> profile>, <Rule '/static/<filename>' (HEAD, OPTIONS, GET) -> static>, <Rule '/user/<id>/' (HEAD, OPTIONS, GET) -> profile>])

In this case, this confirms that the endpoint is correctly set.Here is an example showcasing both plain flask and flask-classy:

from app import app, modelsfrom flask import g, redirect, url_for, render_template, requestfrom flask.ext.classy import FlaskView, route@app.route('/user/<int:id>', strict_slashes=False)@app.route('/user/<int:id>/<username>', strict_slashes=False)def profile(id, username=None):    user = models.User.query.get_or_404(id)    if user.clean_username != username:        return redirect(url_for('profile', id=id, username=user.clean_username))    return render_template('profile.html', user=user)class ClassyUsersView(FlaskView):    @route('/<int:id>', strict_slashes=False)    @route('/<int:id>/<username>', strict_slashes=False, endpoint='classy_profile')    def profile(self, id, username=None):        user = models.User.query.get_or_404(id)        if user.clean_username != username:            return redirect(url_for('classy_profile', id=id, username=user.clean_username))        return render_template('profile.html', user=user)ClassyUsersView.register(app)

They have different endpoints, which you need to take into account for url_for:

>>> app.url_mapMap([<Rule '/classyusers/<id>/<username>' (HEAD, OPTIONS, GET) -> classy_profile>, <Rule '/user/<id>/<username>' (HEAD, OPTIONS, GET) -> profile>, <Rule '/classyusers/<id>' (HEAD, OPTIONS, GET) -> ClassyUsersView:profile_1>, <Rule '/static/<filename>' (HEAD, OPTIONS, GET) -> static>, <Rule '/user/<id>' (HEAD, OPTIONS, GET) -> profile>])

Without flask-classy the name of the endpoint is the function name, but as you've found out, this is different for when using classy, and you can either look at the endpoint name with url_map() or assign it in your route with @route(..., endpoint='name').

less redirects:

To respond to the urls you posted while minimizing the amount of redirects, you need to use strict_slashes=False, this will make sure to handle requests that are not terminated with a / instead of redirecting them with a 301 redirect to their /-terminated counterpart:

@app.route('/user/<int:id>', strict_slashes=False)@app.route('/user/<int:id>/<username>', strict_slashes=False)def profile(id, username=None):    user = models.User.query.get_or_404(id)    if user.clean_username != username:        return redirect(url_for('profile', id=id, username=user.clean_username))    return render_template('profile.html', user=user)

here is the result:

>>> client = app.test_client()>>> def check(url):...     r = client.get(url)...     return r.status, r.headers.get('location')... >>> check('/user/123')('302 FOUND', 'http://localhost/user/123/johndoe')>>> check('/user/123/')('302 FOUND', 'http://localhost/user/123/johndoe')>>> check('/user/123/foo')('302 FOUND', 'http://localhost/user/123/johndoe')>>> check('/user/123/johndoe')('200 OK', None)>>> check('/user/123/johndoe/')('200 OK', None)>>> check('/user/125698')('404 NOT FOUND', None)

Behavior of strict_slashes:

with strict_slashes=FalseURL                         Redirects/points to              # of redirects===========================================================================/user/123                   302 /user/123/clean_username          1/user/123/                  302 /user/123/clean_username          1/user/123/foo               302 /user/123/clean_username          1/user/123/foo/              302 /user/123/clean_username          1/user/123/clean_username    302 /user/123/clean_username          1/user/123/clean_username/   200 /user/123/clean_username/         0/user/125698                404with strict_slashes=True (the default)any non '/'-terminated urls redirect to their '/'-terminated counterpartURL                         Redirects/points to              # of redirects===========================================================================/user/123                   301 /user/123/                        2/user/123/foo               301 /user/123/foo/                    2/user/123/clean_username    301 /user/123/clean_username/         1/user/123/                  302 /user/123/clean_username/         1/user/123/foo/              302 /user/123/clean_username/         1/user/123/clean_username/   200 /user/123/clean_username/         0/user/125698                404example:"/user/123/foo" not terminated with '/' -> redirects to "/user/123/foo/""/user/123/foo/" -> redirects to "/user/123/clean_username/"

I believe it does exactly what your test matrix is about :)

You've almost got it. defaults is what you want. Here is how it works:

@route('/<int:id>/<username>/')@route('/<int:id>/', defaults={'username': None})def profile(id, username):    user = User.query.get_or_404(id)    if username is None or user.clean_username != username:        return redirect(url_for('profile', id=id, username=user.clean_username))    return render_template('user/profile.html', user=user)

defaults is a dict with default values for all route parameters that are not in the rule. Here, in the second route decorator there is no username parameter in the rule, so you have to set it in defaults.

Well, it looks like my original code actually worked. Flask-Classy was the issue here (and since this question has a bounty, I can't delete it).

I forgot that Flask-Classy renames routes, so instead of url_for('ClassName:profile'), I'd have to select the outermost decorator's route:

url_for('ClassName:profile_1')

An alternative would be to explicitly specify an endpoint to the route:

@route('/<int:id>/<username>/', endpoint='ClassName:profile')