Django template tag for reversing date-based URLs.

date_url.py

from django import template
from django.template import defaulttags, Parser, FilterExpression
from django.template.defaulttags import URLNode

register = template.Library()


class DateURLNode(URLNode):
    def __init__(self, *args, **kwargs):
        super(DateURLNode, self).__init__(*args, **kwargs)
        self.date = self.args[0]
        self.args = self.args[1:]

    def render(self, context):
        # Transform the date into kwargs as if the date parts were passed as
        # string literals in the template.
        date = self.date.resolve(context)
        dummy_parser = Parser('')
        self.kwargs['year'] = FilterExpression('"%s"' % date.strftime('%Y'),
            dummy_parser)
        self.kwargs['month'] = FilterExpression('"%s"' % date.strftime('%m'),
            dummy_parser)
        self.kwargs['day'] = FilterExpression('"%s"' % date.strftime('%d'),
            dummy_parser)
        return super(DateURLNode, self).render(context)


@register.tag
def date_url(parser, token):
    '''A derivative of {% url %} that handles date based URLs.

    The passed date will be passed as `year`, `month`, and `day` kwargs
    to the {% url %} code.'''
    url_node = defaulttags.url(parser, token)
    return DateURLNode(url_node.view_name, url_node.args, url_node.kwargs,
        url_node.asvar)