I had the following code:
from django.core.urlresolvers import reverse
class UserProfileView(FormView):
template_name = 'profile.html'
form_class = UserProfileForm
success_url = reverse('index')
When the code above runs, an error is thrown:
django.core.exceptions.ImproperlyConfigured: The included urlconf 'config.urls' does not appear to have any patterns in it. If you see valid patterns in the file then the issue is probably caused by a circular import.
There are two solutions to this problem, solution one:
from django.core.urlresolvers import reverse_lazy
class UserProfileView(FormView):
template_name = 'profile.html'
form_class = UserProfileForm
success_url = reverse_lazy('index') # use reverse_lazy instead of reverse
Solution 2:
from django.core.urlresolvers import reverse
class UserProfileView(FormView):
template_name = 'profile.html'
form_class = UserProfileForm
def get_success_url(self): # override this function if you want to use reverse
return reverse('index')
According to Django's document, reverse_lazy should be used instead of reverse when your project's URLConf is not loaded. The documentation specifically points out that reverse_lazy should be used in the following situation:
providing a reversed URL as the url attribute of a generic class-based view. (this is the situation I encountered)
providing a reversed URL to a decorator (such as the login_url argument for the django.contrib.auth.decorators.permission_required() decorator).
providing a reversed URL as a default value for a parameter in a function’s signature.
It is unclear when URLConf is loaded. At least I cannot find the documentation on this topic. So if the above error occurs again, try reverse_lazy
