Added support for time zones. Thanks Luke Plant for the review. Fixed #2626.

For more information on this project, see this thread:
http://groups.google.com/group/django-developers/browse_thread/thread/cf0423bbb85b1bbf



git-svn-id: http://code.djangoproject.com/svn/django/trunk@17106 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/utils/cache.py

@@ -25,6 +25,7 @@ from django.conf import settings
 from django.core.cache import get_cache
 from django.utils.encoding import smart_str, iri_to_uri
 from django.utils.http import http_date
+from django.utils.timezone import get_current_timezone_name
 from django.utils.translation import get_language
 
 cc_delim_re = re.compile(r'\s*,\s*')
@@ -157,12 +158,14 @@ def has_vary_header(response, header_query):
     return header_query.lower() in existing_headers
 
 def _i18n_cache_key_suffix(request, cache_key):
-    """If enabled, returns the cache key ending with a locale."""
+    """If necessary, adds the current locale or time zone to the cache key."""
     if settings.USE_I18N or settings.USE_L10N:
         # first check if LocaleMiddleware or another middleware added
         # LANGUAGE_CODE to request, then fall back to the active language
         # which in turn can also fall back to settings.LANGUAGE_CODE
         cache_key += '.%s' % getattr(request, 'LANGUAGE_CODE', get_language())
+    if settings.USE_TZ:
+        cache_key += '.%s' % get_current_timezone_name()
     return cache_key
 
 def _generate_cache_key(request, method, headerlist, key_prefix):