python - How is django's default cache invalidated by an app -

i've had disable django's cache middleware;

middleware_classes = (     #'django.middleware.cache.updatecachemiddleware',     ...     #'django.middleware.cache.fetchfromcachemiddleware', ) 

this because caching views default, causing incorrect information rendered because our methods don't invalidate cache.

i'm familiar writing custom cache methods models , necessary signals delete cache keys, if django creating cache keys itself, how delete correct keys when change object example?