Fixed #27225 -- Added "Age" header when fetching cached responses.

Co-Authored-By: Author: Alexander Lazarević <laza@e11bits.com>
This commit is contained in:
Rinat Khabibiev 2016-09-15 08:41:07 +03:00 committed by Mariusz Felisiak
parent 4b1cd8edc1
commit 3580b47ed3
2 changed files with 43 additions and 0 deletions

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@ -43,6 +43,8 @@ More details about how the caching works:
""" """
import time
from django.conf import settings from django.conf import settings
from django.core.cache import DEFAULT_CACHE_ALIAS, caches from django.core.cache import DEFAULT_CACHE_ALIAS, caches
from django.utils.cache import ( from django.utils.cache import (
@ -53,6 +55,7 @@ from django.utils.cache import (
patch_response_headers, patch_response_headers,
) )
from django.utils.deprecation import MiddlewareMixin from django.utils.deprecation import MiddlewareMixin
from django.utils.http import parse_http_date_safe
class UpdateCacheMiddleware(MiddlewareMixin): class UpdateCacheMiddleware(MiddlewareMixin):
@ -171,6 +174,15 @@ class FetchFromCacheMiddleware(MiddlewareMixin):
request._cache_update_cache = True request._cache_update_cache = True
return None # No cache information available, need to rebuild. 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 # hit, return cached response
request._cache_update_cache = False request._cache_update_cache = False
return response return response

31
tests/cache/tests.py vendored
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@ -2752,6 +2752,37 @@ class CacheMiddlewareTest(SimpleTestCase):
self.assertIsNot(thread_caches[0], thread_caches[1]) 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( @override_settings(
CACHE_MIDDLEWARE_KEY_PREFIX="settingsprefix", CACHE_MIDDLEWARE_KEY_PREFIX="settingsprefix",