Fixed #30765 -- Made cache_page decorator take precedence over max-age Cache-Control directive.

2 files changed, 15 insertions, 10 deletions

diff --git a/django/middleware/cache.py b/django/middleware/cache.py
index 6b320f1db5..9705270b59 100644
--- a/django/middleware/cache.py
+++ b/django/middleware/cache.py
@@ -63,6 +63,7 @@ class UpdateCacheMiddleware(MiddlewareMixin):
     """
     def __init__(self, get_response=None):
         self.cache_timeout = settings.CACHE_MIDDLEWARE_SECONDS
+        self.page_timeout = None
         self.key_prefix = settings.CACHE_MIDDLEWARE_KEY_PREFIX
         self.cache_alias = settings.CACHE_MIDDLEWARE_ALIAS
         self.cache = caches[self.cache_alias]
@@ -89,15 +90,18 @@ class UpdateCacheMiddleware(MiddlewareMixin):
         if 'private' in response.get('Cache-Control', ()):
             return response
 
-        # Try to get the timeout from the "max-age" section of the "Cache-
-        # Control" header before reverting to using the default cache_timeout
-        # length.
-        timeout = get_max_age(response)
+        # Page timeout takes precedence over the "max-age" and the default
+        # cache timeout.
+        timeout = self.page_timeout
         if timeout is None:
-            timeout = self.cache_timeout
-        elif timeout == 0:
-            # max-age was set to 0, don't bother caching.
-            return response
+            # The timeout from the "max-age" section of the "Cache-Control"
+            # header takes precedence over the default cache timeout.
+            timeout = get_max_age(response)
+            if timeout is None:
+                timeout = self.cache_timeout
+            elif timeout == 0:
+                # max-age was set to 0, don't cache.
+                return response
         patch_response_headers(response, timeout)
         if timeout and response.status_code == 200:
             cache_key = learn_cache_key(request, response, timeout, self.key_prefix, cache=self.cache)
@@ -160,7 +164,7 @@ class CacheMiddleware(UpdateCacheMiddleware, FetchFromCacheMiddleware):
     Also used as the hook point for the cache decorator, which is generated
     using the decorator-from-middleware utility.
     """
-    def __init__(self, get_response=None, cache_timeout=None, **kwargs):
+    def __init__(self, get_response=None, cache_timeout=None, page_timeout=None, **kwargs):
         self.get_response = get_response
         # We need to differentiate between "provided, but using default value",
         # and "not provided". If the value is provided using a default, then
@@ -186,4 +190,5 @@ class CacheMiddleware(UpdateCacheMiddleware, FetchFromCacheMiddleware):
         if cache_timeout is None:
             cache_timeout = settings.CACHE_MIDDLEWARE_SECONDS
         self.cache_timeout = cache_timeout
+        self.page_timeout = page_timeout
         self.cache = caches[self.cache_alias]
diff --git a/django/views/decorators/cache.py b/django/views/decorators/cache.py
index 9658bd6ba2..773cf0c2c6 100644
--- a/django/views/decorators/cache.py
+++ b/django/views/decorators/cache.py
@@ -20,7 +20,7 @@ def cache_page(timeout, *, cache=None, key_prefix=None):
     into account on caching -- just like the middleware does.
     """
     return decorator_from_middleware_with_args(CacheMiddleware)(
-        cache_timeout=timeout, cache_alias=cache, key_prefix=key_prefix
+        page_timeout=timeout, cache_alias=cache, key_prefix=key_prefix,
     )