Opened 10 years ago
Last modified 10 years ago
#24035 closed Bug
Poor/incorrect documentation for CACHE_MIDDLEWARE_KEY_PREFIX in relation to CACHES[alias]['KEY_PREFIX'] — at Initial Version
| Reported by: | Frankie Robertson | Owned by: | Frankie Robertson |
|---|---|---|---|
| Component: | Documentation | Version: | dev |
| Severity: | Normal | Keywords: | |
| Cc: | Triage Stage: | Accepted | |
| Has patch: | no | Needs documentation: | no |
| Needs tests: | no | Patch needs improvement: | no |
| Easy pickings: | no | UI/UX: | no |
Description
The interaction between CACHES[alias]KEY_PREFIX, CACHE_MIDDLEWARE_KEY_PREFIX and @cache_page(... key_prefix) is poorly documented. It should be made explicit that KEY_PREFIX is always used and combined with CACHE_MIDDLEWARE_KEY_PREFIX or @cache_page(... key_prefix)
Changes should be made to both ref/settings and topics/cache.
The paragraph at the bottom of https://docs.djangoproject.com/en/dev/topics/cache/#the-per-view-cache is particularly troublesome:
"The two settings can also be combined. If you specify a cache and a key_prefix, you will get all the settings of the requested cache alias, but with the key_prefix overridden.
Having looked through the source it appears as though the setting CACHE_MIDDLEWARE_KEY_PREFIX OR the argument to @cache_page is combined with the rest of the cache key using django.utils.cache.get_cache_key which is then combined with the CACHES[alias]KEY_PREFIX using key_func.