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Asked: 2026-05-11T05:07:25+00:00

I need to perform case-insensitive queries on username by default when using the Django

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I need to perform case-insensitive queries on username by default when using the Django Auth framework.

I tried fixing the issue by writing a custom subclass of Queryset and overriding the _filter_or_exclude method and then using that subclass in a custom manager for the User model-

from django.db.models import Manager from django.db.models.query import QuerySet from django.contrib.auth.models import UserManager  class MyQuerySet(QuerySet):     def _filter_or_exclude(self, negate, *args, **kwargs):         if 'username' in kwargs:             kwargs['username__iexact'] = kwargs['username']             del kwargs['username']         return super(MyQuerySet, self)._filter_or_exclude(negate, *args, **kwargs)  class MyUserManager(UserManager):     def get_query_set(self):         return MyQuerySet(self.model)  User.objects = MyUserManager()

But this approach didn’t work and I am getting an weird error when I try doing User.objects.get(username='Foo').

Any help would be appreciated.

Update: I am including the exact error that I am getting.

/usr/lib/python2.5/site-packages/django/db/models/query.py in get(self, *args, **kwargs)     295         keyword arguments.     296         ''' --> 297         clone = self.filter(*args, **kwargs)     298         num = len(clone)     299         if num == 1:  /usr/lib/python2.5/site-packages/django/db/models/query.py in filter(self, *args, **kwargs)     481         set.     482         ''' --> 483         return self._filter_or_exclude(False, *args, **kwargs)     484      485     def exclude(self, *args, **kwargs):  /home/ghoseb/src/git/ocricket.git/ocricket/user/models.py in _filter_or_exclude(self, negate, *args, **kwargs)      38             kwargs['username__iexact'] = kwargs['username']      39             del kwargs['username'] ---> 40         return super(MyQuerySet, self)._filter_or_exclude(negate, *args, **kwargs)      41       42 class MyUserManager(UserManager):  /usr/lib/python2.5/site-packages/django/db/models/query.py in _filter_or_exclude(self, negate, *args, **kwargs)     499             clone.query.add_q(~Q(*args, **kwargs))     500         else: --> 501             clone.query.add_q(Q(*args, **kwargs))     502         return clone     503   /usr/lib/python2.5/django/db/models/sql/query.py in add_q(self, q_object, used_aliases)  /usr/lib/python2.5/django/db/models/sql/query.py in add_filter(self, filter_expr, connector, negate, trim, can_reuse, process_extras)  /usr/lib/python2.5/django/db/models/sql/query.py in get_meta(self)  <type 'exceptions.AttributeError'>: 'NoneType' object has no attribute '_meta'

Update: By the way, I just wanted to mention that when I copy the logic inside my _filter_or_exclude method into the actual QuerySet class, it works flawlessly.

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1 Answer

  1. Managers can’t be added to classes with simple attribute assignment (User.objects = MyManager()). Look at the ModelBase metaclass (db/models/base.py) to see what all is done for you behind the scenes when you subclass Model.

    You should be able to make it work with User.add_to_class('objects', MyManager()). Alternatively, you could make a proxy subclass of User and add the manager there.

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