CSRF Protection Issue with Django OAuth Toolkit

Based on the information provided, you're encountering a CSRF error with the /o/token endpoint despite the csrf_exempt decorator being applied to the TokenView in django-oauth-toolkit.

Possible Causes

There are several reasons why you might still be getting CSRF errors despite the view being marked as exempt:

1. Middleware Order: The CSRF middleware might be processing the request before the csrf_exempt decorator has a chance to take effect. In Django, middleware order matters.

2. URL Configuration: The URL pattern might be incorrectly configured, causing the request to be routed to a different view that doesn't have the csrf_exempt decorator.

3. Decorator Application: The csrf_exempt decorator might not be properly applied to the class-based view.

Solutions to Try

1. Check Your Middleware Configuration

Ensure that the CSRF middleware is correctly configured in your settings:

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MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',  # This is the CSRF middleware
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
    # ... other middleware
]

2. Verify URL Configuration

Check that your URLs are correctly configured to use the TokenView from django-oauth-toolkit:

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# In your urls.py
from oauth2_provider import views as oauth2_views

urlpatterns = [
    # ...
    path('o/', include('oauth2_provider.urls', namespace='oauth2_provider')),
    # ...
]

3. Apply CSRF Exempt Manually

If the issue persists, you can try to manually exempt the view in your URL configuration:

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from django.views.decorators.csrf import csrf_exempt
from oauth2_provider import views as oauth2_views

urlpatterns = [
    # ...
    path('o/token/', csrf_exempt(oauth2_views.TokenView.as_view()), name='token'),
    # ...
]

4. Use Edge Case Solutions

As mentioned in the Django documentation, there are edge cases where you might need to use a combination of decorators:

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from django.views.decorators.csrf import csrf_exempt, requires_csrf_token

# Apply both decorators if needed
@csrf_exempt
@requires_csrf_token
def your_view(request):
    # Your view logic
    pass

Additional Debugging Steps

1. Check if there are any custom middleware in your project that might be interfering with the CSRF exemption.

2. Verify that the request is actually reaching the TokenView by adding logging or debugging statements.

3. Check if there are any proxy servers or load balancers that might be stripping headers or cookies.

If you continue to face issues, you might need to examine how django-oauth-toolkit is integrated with your specific Django setup, as there could be project-specific configurations affecting the CSRF behavior.