cms.middleware.user.py

"""
This is a temporary fix for django-cms 3.0 failing to logout
a user correctly (I don't currently have the time to setup a
PR). The fix goes into cms.middleware.user 

The problem is manifest in unit tests where there are multiple
tests that repeatedly login/logout using Django's test Client()
and which use fixtures referencing auth_user.

The first test that runs will install the fixtures fine. Any
subsequent tests will fail creating new auth_user objects:

IntegrityError: (1452, 'Cannot add or update a child row: a 
foreign key constraint fails (`test_shrebo`.`cms_pageuser`, 
CONSTRAINT `created_by_id_refs_id_9da6953b` FOREIGN KEY 
(`created_by_id`) REFERENCES `auth_user` (`id`))')

The problem appears in cms.signals.permissions.post_save_user 
while processing post_save_user user, but the origin of the error
is due to CurrentUserMiddleware not resetting the user object
in thread local. This causes subsequent test runs to set a
created_by user object that no longer exists.   

Usage without updating Django CMS:
   add the below logout_user somewhere in your (at least test) code. 

TODO incorporate as a PR into 
"""
from django.dispatch import receiver
from django.contrib.auth.signals import user_logged_out

class CurrentUserMiddleware(object):
    def process_request(self, request):
        from cms.utils.permissions import set_current_user
        set_current_user(getattr(request, 'user', None))
        
@receiver(user_logged_out)
def logout_user(sender, **kwargs):
    from cms.utils.permissions import set_current_user
    set_current_user(None)