Login

Template tag to clear cached template fragment

Author:
joao.coelho
Posted:
November 16, 2009
Language:
Python
Version:
1.1
Score:
0 (after 0 ratings)

This is a custom template tag that clears the cache that was created with the cache tag.

{% load clearcache %}
{% clearcache [fragment_name] [var1] [var2] .. %}

Create app/templatetags folder with init.py and copy code into clearcache.py file.

polls/
    templatetags/
        __init__.py
        clearcache.py

Based on django.templatetags.cache. See Django docs on custom template tags

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
from django import template
from django.template import resolve_variable
from django.core.cache import cache
from django.utils.http import urlquote
from django.utils.hashcompat import md5_constructor

register = template.Library()

class ClearCacheNode(template.Node):
    def __init__(self, fragment_name, vary_on):
        self.fragment_name = fragment_name
        self.vary_on = vary_on

    def render(self, context):
        # Build a unicode key for this fragment and all vary-on's.
        args = md5_constructor(u':'.join([urlquote(resolve_variable(var, context)) for var in self.vary_on]))
        cache_key = 'template.cache.%s.%s' % (self.fragment_name, args.hexdigest())
        cache.delete(cache_key)
        return ''

def clearcache(parser, token):
    """
    This will clear the cache for a template fragment

    Usage::

        {% load clearcache %}
        {% clearcache [fragment_name] %}

    This tag also supports varying by a list of arguments::

        {% load clearcache %}
        {% clearcache [fragment_name] [var1] [var2] .. %}

    The set of arguments must be the same as the original cache tag (except for expire_time).
    """
    try:
        tokens = token.split_contents()
    except ValueError:
        raise template.TemplateSyntaxError, "%r tag requires at least one argument" % token.contents.split()[0]
    return ClearCacheNode(tokens[1], tokens[2:])

register.tag('clearcache', clearcache)

More like this

  1. Template tag - list punctuation for a list of items by shapiromatron 2 months, 2 weeks ago
  2. JSONRequestMiddleware adds a .json() method to your HttpRequests by cdcarter 2 months, 3 weeks ago
  3. Serializer factory with Django Rest Framework by julio 9 months, 2 weeks ago
  4. Image compression before saving the new model / work with JPG, PNG by Schleidens 10 months, 1 week ago
  5. Help text hyperlinks by sa2812 11 months ago

Comments

Please login first before commenting.