From 3580b47ed31ec85ae89b13618f36bb463e97acc8 Mon Sep 17 00:00:00 2001 From: Rinat Khabibiev Date: Thu, 15 Sep 2016 08:41:07 +0300 Subject: [PATCH] Fixed #27225 -- Added "Age" header when fetching cached responses. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Co-Authored-By: Author: Alexander Lazarević --- django/middleware/cache.py | 12 ++++++++++++ tests/cache/tests.py | 31 +++++++++++++++++++++++++++++++ 2 files changed, 43 insertions(+) diff --git a/django/middleware/cache.py b/django/middleware/cache.py index 0fdffe1bbee..196b1995ffb 100644 --- a/django/middleware/cache.py +++ b/django/middleware/cache.py @@ -43,6 +43,8 @@ More details about how the caching works: """ +import time + from django.conf import settings from django.core.cache import DEFAULT_CACHE_ALIAS, caches from django.utils.cache import ( @@ -53,6 +55,7 @@ from django.utils.cache import ( patch_response_headers, ) from django.utils.deprecation import MiddlewareMixin +from django.utils.http import parse_http_date_safe class UpdateCacheMiddleware(MiddlewareMixin): @@ -171,6 +174,15 @@ class FetchFromCacheMiddleware(MiddlewareMixin): request._cache_update_cache = True return None # No cache information available, need to rebuild. + # Derive the age estimation of the cached response. + if (max_age_seconds := get_max_age(response)) is not None and ( + expires_timestamp := parse_http_date_safe(response["Expires"]) + ) is not None: + now_timestamp = int(time.time()) + remaining_seconds = expires_timestamp - now_timestamp + # Use Age: 0 if local clock got turned back. + response["Age"] = max(0, max_age_seconds - remaining_seconds) + # hit, return cached response request._cache_update_cache = False return response diff --git a/tests/cache/tests.py b/tests/cache/tests.py index e6ebb718f1a..978efdd9d38 100644 --- a/tests/cache/tests.py +++ b/tests/cache/tests.py @@ -2752,6 +2752,37 @@ class CacheMiddlewareTest(SimpleTestCase): self.assertIsNot(thread_caches[0], thread_caches[1]) + def test_cache_control_max_age(self): + view = cache_page(2)(hello_world_view) + request = self.factory.get("/view/") + + # First request. Freshly created response gets returned with no Age + # header. + with mock.patch.object( + time, "time", return_value=1468749600 + ): # Sun, 17 Jul 2016 10:00:00 GMT + response = view(request, 1) + response.close() + self.assertIn("Expires", response) + self.assertEqual(response["Expires"], "Sun, 17 Jul 2016 10:00:02 GMT") + self.assertIn("Cache-Control", response) + self.assertEqual(response["Cache-Control"], "max-age=2") + self.assertNotIn("Age", response) + + # Second request one second later. Response from the cache gets + # returned with an Age header set to 1 (second). + with mock.patch.object( + time, "time", return_value=1468749601 + ): # Sun, 17 Jul 2016 10:00:01 GMT + response = view(request, 1) + response.close() + self.assertIn("Expires", response) + self.assertEqual(response["Expires"], "Sun, 17 Jul 2016 10:00:02 GMT") + self.assertIn("Cache-Control", response) + self.assertEqual(response["Cache-Control"], "max-age=2") + self.assertIn("Age", response) + self.assertEqual(response["Age"], "1") + @override_settings( CACHE_MIDDLEWARE_KEY_PREFIX="settingsprefix",