Anonymous committed 0de1aba

[1.3.X] Fixed #15499 -- Ensure that cache control headers don't try to set public and private as a result of multiple calls to patch_cache_control with different arguments. Thanks to AndiDog for the report and patch.

Backport of r16657 from trunk.

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Files changed (3)


     if 'max-age' in cc and 'max_age' in kwargs:
         kwargs['max_age'] = min(cc['max-age'], kwargs['max_age'])
+    # Allow overriding private caching and vice versa
+    if 'private' in cc and 'public' in kwargs:
+        del cc['private']
+    elif 'public' in cc and 'private' in kwargs:
+        del cc['public']
     for (k, v) in kwargs.items():
         cc[k.replace('_', '-')] = v
     cc = ', '.join([dictvalue(el) for el in cc.items()])


 This decorator takes care of sending out the appropriate HTTP header behind the
+Note that the cache control settings "private" and "public" are mutually
+exclusive. The decorator ensures that the "public" directive is removed if
+"private" should be set (and vice versa). An example use of the two directives
+would be a blog site that offers both private and public entries. Public
+entries may be cached on any shared cache. The following code uses
+``patch_cache_control``, the manual way to modify the cache control header
+(it is internally called by the ``cache_control`` decorator)::
+    from django.views.decorators.cache import patch_cache_control
+    from django.views.decorators.vary import vary_on_cookie
+    @vary_on_cookie
+    def list_blog_entries_view(request):
+        if request.user.is_anonymous():
+            response = render_only_public_entries()
+            patch_cache_control(response, public=True)
+        else:
+            response = render_private_and_public_entries(request.user)
+            patch_cache_control(response, private=True)
+        return response
 There are a few other ways to control cache parameters. For example, HTTP
 allows applications to do the following:


 # Uses whatever cache backend is set in the test settings file.
 import os
+import re
 import tempfile
 import time
 import warnings
 from django.test.utils import get_warnings_state, restore_warnings_state
 from django.utils import translation
 from django.utils import unittest
-from django.utils.cache import patch_vary_headers, get_cache_key, learn_cache_key
+from django.utils.cache import patch_vary_headers, get_cache_key, learn_cache_key, patch_cache_control
 from django.utils.hashcompat import md5_constructor
 from django.views.decorators.cache import cache_page
         learn_cache_key(request, response)
         self.assertEqual(get_cache_key(request), 'views.decorators.cache.cache_page.settingsprefix.HEAD.a8c87a3d8c44853d7f79474f7ffe4ad5.d41d8cd98f00b204e9800998ecf8427e')
+    def test_patch_cache_control(self):
+        tests = (
+            # Initial Cache-Control, kwargs to patch_cache_control, expected Cache-Control parts
+            (None, {'private' : True}, set(['private'])),
+            # Test whether private/public attributes are mutually exclusive
+            ('private', {'private' : True}, set(['private'])),
+            ('private', {'public' : True}, set(['public'])),
+            ('public', {'public' : True}, set(['public'])),
+            ('public', {'private' : True}, set(['private'])),
+            ('must-revalidate,max-age=60,private', {'public' : True}, set(['must-revalidate', 'max-age=60', 'public'])),
+            ('must-revalidate,max-age=60,public', {'private' : True}, set(['must-revalidate', 'max-age=60', 'private'])),
+            ('must-revalidate,max-age=60', {'public' : True}, set(['must-revalidate', 'max-age=60', 'public'])),
+        )
+        cc_delim_re = re.compile(r'\s*,\s*')
+        for initial_cc, newheaders, expected_cc in tests:
+            response = HttpResponse()
+            if initial_cc is not None:
+                response['Cache-Control'] = initial_cc
+            patch_cache_control(response, **newheaders)
+            parts = set(cc_delim_re.split(response['Cache-Control']))
+            self.assertEqual(parts, expected_cc)
 class PrefixedCacheUtils(CacheUtils):
     def setUp(self):
         super(PrefixedCacheUtils, self).setUp()