bettercache template tags¶

Currently, the only tag provided is a replacement for Django’s builtin {% cache %} tag, which makes it easier to work with nested blocks.

cache¶

Better Cache provides a replacement for the default cache template tag library from Django. It is a better version of {% cache %}.

What is better about Better Cache’s version of the cache tag?

Nested cache fragments inherit the variables their parent fragments key on

Parent cache fragments can be given additional keys by their child cache fragments

An example:

{% cache 500 "outer" x %}
    y = {{ y }}<br />
    {% cache 500 "inner" y %}
        x = {{ x }}<br />
    {% endcache %}
{% endcache %}

In the default {% cache %} tag from Django, the inner fragment will not be rerendered when x changes, because only the outer fragment uses that as a key variable. The outer fragment will not update with y changes, because only the inner fragment uses that.

With Better Cache, x and y affect both, so fragments will be re-rendered when any important variable changes.

Default Keys¶

Better Cache also allows a syntax of giving defaults to key variables:

{% cache 500 "test" x=10 %}
    ...
{% endcache %}

This allows the block to be rendered as if x had the value 10, caching the result and reusing if later if x really does exist and have that value later.

Controlling inheritence¶

You don’t always want the outer cache fragments to invalidate when variables only important to the inner fragment changes. In some cases, the inner fragment is allowed to get stale if it stays cached longer as part of the parent, so we want a way to disable the inheritence of the variables.

You can do this with the local modifier. All modifiers after the local will affect only this cache fragment, not its parent.

{% cache 500 "outer" x %}
    y = {{ y }}<br />
    {% cache 500 "inner" local y %}
        x = {{ x }}<br />
    {% endcache %}
{% endcache %}