Django 1.9: 'AnonymousUser' object is not iterable - django

Question

I was working on a Django 1.9 project, and suddenly this error popped up when I attempted to view my site's home page as a logged-out user.
Environment:
Request Method: GET
Request URL: http://127.0.0.1:8000/
Django Version: 1.9.7
Python Version: 2.7.10
Installed Applications:
['django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.sites',
'django.contrib.staticfiles',
'captcha',
'debug_toolbar',
'django_extensions',
'djstripe',
'crm',
'launch',
'rentals',
'widget_tweaks']
Installed Middleware:
[u'debug_toolbar.middleware.DebugToolbarMiddleware',
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'django.contrib.auth.middleware.AuthenticationMiddleware',
'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
'django.contrib.messages.middleware.MessageMiddleware',
'django.middleware.clickjacking.XFrameOptionsMiddleware']
Traceback:
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
174. response = self.process_exception_by_middleware(e, request)
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/core/handlers/base.py" in get_response
172. response = response.render()
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/template/response.py" in render
160. self.content = self.rendered_content
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/template/response.py" in rendered_content
137. content = template.render(context, self._request)
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/template/backends/django.py" in render
95. return self.template.render(context)
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/template/base.py" in render
204. with context.bind_template(self):
File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/contextlib.py" in __enter__
17. return self.gen.next()
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/debug_toolbar/panels/templates/panel.py" in _request_context_bind_template
79. context = processor(self.request)
File "/Users/me/projects/rentalguru/src/rentals/processors.py" in allCategories
4. expense_categories = ExpenseCategory.objects.filter(user=request.user)
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/db/models/manager.py" in manager_method
122. return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/db/models/query.py" in filter
790. return self._filter_or_exclude(False, *args, **kwargs)
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/db/models/query.py" in _filter_or_exclude
808. clone.query.add_q(Q(*args, **kwargs))
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/db/models/sql/query.py" in add_q
1243. clause, _ = self._add_q(q_object, self.used_aliases)
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/db/models/sql/query.py" in _add_q
1269. allow_joins=allow_joins, split_subq=split_subq,
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/db/models/sql/query.py" in build_filter
1174. self.check_related_objects(field, value, opts)
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/db/models/sql/query.py" in check_related_objects
1073. for v in value:
File "/Users/me/projects/rentalguru/lib/python2.7/site-packages/django/utils/functional.py" in inner
205. return func(self._wrapped, *args)
Exception Type: TypeError at /
Exception Value: 'AnonymousUser' object is not iterable
I'm not sure what would be causing this, and there's only one Google search result (for this site) for this error. I searched the code for the is_authenticated() method and didn't find anything, so I'm unsure where to turn. Working through the stack trace didn't show any useful (for me) information.
Here is my view:
class HomePageView(TemplateView):
template_name = 'home.html'
No login decorators or wrapped functions that I can tell.
Let me know if I need to post anything else.
EDIT: Asked for the model, here is the offending context processor instead:
def allCategories(request):
expense_categories = ExpenseCategory.objects.filter(user=request.user)
tags = {'categories': expense_categories}
return tags

Answer 1

I just stumbled myself upon this error. Thankfully the answer was provided in the comments:
As you said you tried to view home page with logged out user and this ExpenseCategory.objects.filter(user=request.user) filtering of Anonymous user (because you are logged out now) seems to be the culprit. Either you should allow only a authenticated user to this view or handle the case where your user is Anonymous
As for myself, I had a view, where I was filtering on a model based on the current user, which apparantly fails, when the user is the AnonymousUser.
I fixed this by adding a check:
if request.user.is_active:
expense_categories = ExpenseCategory.objects.filter(user=request.user)
Note that some people seem to prefer to check request.user.is_authenticated instead.
If you are dealing with a view that shall be accessed by logged in users only, you can also use the #login_required decorator.
For reference:
https://docs.djangoproject.com/en/1.11/ref/contrib/auth/#django.contrib.auth.models.User.is_active
https://docs.djangoproject.com/en/1.11/ref/contrib/auth/#django.contrib.auth.models.User.is_authenticated
https://docs.djangoproject.com/en/1.11/topics/auth/default/#django.contrib.auth.decorators.login_required