Module cache
Cache middleware. If enabled, each Django-powered page will be cached based on
URL. The canonical way to enable cache middleware is to set
``UpdateCacheMiddleware`` as your first piece of middleware, and
``FetchFromCacheMiddleware`` as the last::
MIDDLEWARE = [
'django.middleware.cache.UpdateCacheMiddleware',
...
'django.middleware.cache.FetchFromCacheMiddleware'
]
This is counter-intuitive, but correct: ``UpdateCacheMiddleware`` needs to run
last during the response phase, which processes middleware bottom-up;
``FetchFromCacheMiddleware`` needs to run last during the request phase, which
processes middleware top-down.
The single-class ``CacheMiddleware`` can be used for some simple sites.
However, if any other piece of middleware needs to affect the cache key, you'll
need to use the two-part ``UpdateCacheMiddleware`` and
``FetchFromCacheMiddleware``. This'll most often happen when you're using
Django's ``LocaleMiddleware``.
More details about how the caching works:
* Only GET or HEAD-requests with status code 200 are cached.
* The number of seconds each page is stored for is set by the "max-age" section
of the response's "Cache-Control" header, falling back to the
CACHE_MIDDLEWARE_SECONDS setting if the section was not found.
* This middleware expects that a HEAD request is answered with the same response
headers exactly like the corresponding GET request.
* When a hit occurs, a shallow copy of the original response object is returned
from process_request.
* Pages will be cached based on the contents of the request headers listed in
the response's "Vary" header.
* This middleware also sets ETag, Last-Modified, Expires and Cache-Control
headers on the response object.
source linkClasses
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Cache middleware that provides basic behavior for many simple sites.
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Request-phase cache middleware that fetches a page from the cache.
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Response-phase cache middleware that updates the cache if the response is cacheable.