Template tag `get_franchise_gallery_items()` to get recent GalleryItems associated to a specific Category.

turn_tags.py

from django.core.cache import cache
from ella_galleries.models import GalleryItem

@register.assignment_tag
def get_franchise_gallery_items(category_tree_path, results=5):
    """
    Takes a `category_tree_path`, an optional arg `results` and
    returns a list of most recent GalleryItems in the Category.

    Since this is an expensive query, we'll cache the results for
    each category for 10 minutes.

    Usage:
    {% get_franchise_gallery_items 'this-i-know' as recent_gallery_items %}
    {% for item in recent_gallery_items %}
        {{ item }}
    {% endfor %}
    """
    # Check for the results in cache
    key = 'get_franchise_gallery_items:%s' % category_tree_path
    results = cache.get(key)
    if results is not None:
        return results

    # Found nothing in cache, fetch the GalleryItems
    results = GalleryItem.objects.filter(
        gallery__listing__category__tree_path=category_tree_path
    ).order_by('-id')[0:results]

    # Cache and return the results
    cache.set(key, results, 60*10)
    return results