active_menu.py

from django import template

register = template.Library()


@register.simple_tag(takes_context=True)
def active_menu(context, viewnames, css_class="active", **kwargs):
    request = context.get("request")
    match = request.resolver_match
    views = viewnames.split("||")

    for view in views:
        namespace, view_name = view.split(":")
        if match.url_name == view_name and namespace in match.namespaces:
            return css_class

    return ""