CachedCounter is used to cache counters such as photo number in an album.

It uses django.core.cache as backend. CachedCounter acts as a model field and supports atomic increments.

You can use signals to update counter after adding or deleting instances.

Usage

models.py

from django.db import models
from cached_counter.counters import Counter

class Album(models.Model):
    photo_count = Counter("get_photo_count")

    def get_photo_count(self):
        return self.photo_set.count()

getting and updating the counter

# get counter value
print long(album.photo_count)

# atomic increment
album.photo_count += 1

# set the value
album.photo_count = 10

# using counter in django templates
{{ album.photo_count }}

ModelForm helper, that works on virtual fields, useful on perdurable cache backeds, such as django-redis.

from cached_counter.counters import virtual_factory

AlbumForm = virtual_factory(Album)