This is Django app for "timeout-less" caching. It uses Django cache framework in the background, so cache backend configuration is absolutely the same, as it has been. You can use Django cache framework for additional caching as well.
This app consists of two main parts: ICache object and icache template tag.
This is used by icache template tag. Using this, you can provide some real-time data invalidation. Examples are in the bottom of the page.
Methods:
-
incr(key): Increment value, stored by key. If there is no such cache entry, stores 0 by givven key. -
incr_many(keys): Does the same as 'incr', but for the list of keys. -
get_sum(keys): Returns sum of values, stored by givven keys. If some value does'n exist, it is considered to be 0. -
set_versioned(key, value, version): Saves value and version by given key. -
get_versioned(key, version): Returns value, stored by set_versioned, if the stored version is equal to the given one; else returns None and deletes cache entry.
Template tag will cache the contents of a template fragment until the data, used in this fragment, is outdated.
Usage::
{% load icache %}
{% icache [token_1] [token_2] [token_3] ... [token_n] %}
.. some expensive processing ..
{% endicache %}
Each unique set of arguments will result in a unique cache entry.
"Version" of the template fragment - is the sum of values, stored in cache by keys, equal to arguments, passed to tag (is some cache entry doesn't exist, its value is considered to be 0). Rendered template fragment is stored with it's version.
Stored template fragment is considered to be outdated if its current "version" is not equal to the stred one.
In template:
{% load icache}
{% icache 'movies-personal-rating' 'movies' user.id %}
... list of ordered by personal rating movies ...
{% endicache %}
Here, for each user-unique request, a new cache entry with this template fragment is created.
In models.py:
from django_icache import icache
... some imports ...
class Movie(models.Model):
... some code ...
def movie_cache_post_save(sender, **kwargs):
icache.incr('movies') # increments value, stored by 'movies' key
post_save.connect(movie_cache_post_save, sender=Movie)
After saving some Movie object, all stored template fragments, containing
token 'movie', is considered to be outdated.