Fixed django#2541 -- Added helpful error message for CacheMiddleware in the case of CACHE_ANONYMOUS_ONLY=True and uninstalled/unordered AuthenticationMiddleware. Thanks, dummy@habmalnefrage.de

git-svn-id: http://code.djangoproject.com/svn/django/trunk@3603 bcc190cf-cafb-0310-a4f2-bffc1f526a37

Author: adrianholovaty

django/middleware/cache.py

@@ -41,6 +41,9 @@ def __init__(self, cache_timeout=None, key_prefix=None, cache_anonymous_only=Non
 
     def process_request(self, request):
         "Checks whether the page is already cached and returns the cached version if available."
+        if self.cache_anonymous_only:
+            assert hasattr(request, 'user'), "The Django cache middleware with CACHE_MIDDLEWARE_ANONYMOUS_ONLY=True requires authentication middleware to be installed. Edit your MIDDLEWARE_CLASSES setting to insert 'django.contrib.auth.middleware.AuthenticationMiddleware' before the CacheMiddleware."
+
         if not request.method in ('GET', 'HEAD') or request.GET:
             request._cache_update_cache = False
             return None # Don't bother checking the cache.