Listing Handlers

By default Ella can list Publishable in categories using the Listing model. If additional methods of listing, sorting and pagination is required, a plugin can define a ListingHandler. For example if makes sense for a comments plugin to define a ListingHandler that will allow you to list Publishables sorted by number of comments.

Project can define multiple ListingHandler classes and use GET parameters and optional arguments to the {% listing %} template tag to determine which to use on per-request basis.

On top of the default ListingHandler ('ella.core.managers.ModelListingHandler') Ella also provides an optimized RedisListingHandler ('ella.core.cache.redis.RedisListingHandler') to be used on high traffic sites.

Usage

ListingHandler classes a projects is using are defined in settings, a configuration entry for 'default' must always be present:

LISTING_HANDLERS = {
    'default': 'ella.core.managers.ModelListingHandler',
    'comments': 'ella_comments.CommentCountListingHandler',
}

Interface

ListingHandler is justa class that defines two methods - count and get_listings:

from ella.core.managers import ListingHandler

class CommentsListingHandler(ListingHandler):
    def count(self):
        ...

    def get_listings(self, offset=0, count=10):
        ...

The __init__ method of the class accepts folowing aguments: category, children=None, content_types=[], date_range=(), exclude=None

ListingHandler.__init__ arguments

Key	Default	Value
category		Category object
children	NONE	One of NONE, IMMEDIATE and ALL indicating whether to include all Publishables listed in category’s children/descendants.
content_types	[]	ContentType instances to filter on.
date_range	()	Optional date range to list.
exclude	None	A Publishable instance to omit from the result.