Template tag for django-cms which renders hreflang alternate meta-tags for CMS pages as well as app detail pages.

hreflang_templatetag.py

@register.inclusion_tag('templatetags/hreflangs.html', takes_context=True)
def render_hreflangs(context):
    """
    This templatetag renders hreflang alternate tags for all available languages.

    It supports CMS pages and detail pages of app hooks
    The apps detail view needs to have `slug` as last part in the url, eg. /de/produkte-a-z/napura` (slug: napura`)
    :param context:
    :return:
    """
    APP_NAMESPACES_WITH_SLUG_DETAIL_PAGES = ['brand', 'collection', 'news', 'jobs']

    request = context.get('request')
    alternate_languages = [l[0] for l in settings.LANGUAGES if l[0] != request.LANGUAGE_CODE]
    context = {
        'alternatives': []
    }

    for language in alternate_languages:
        try:
            app_namespace = request.current_page.application_namespace  # eg. 'brand' or 'collection'

            # Get alternative url for normal CMS page
            if app_namespace is None:
                url = request.current_page.get_absolute_url(language=language)

            # Get alternative urls for apphook detail pages
            elif app_namespace in APP_NAMESPACES_WITH_SLUG_DETAIL_PAGES:
                view_name = resolve(request.path_info).url_name
                slug = request.path_info.rstrip('/').split('/')[-1]
                view_identifier = '{app}:{view}'.format(app=app_namespace, view=view_name)

                with translation.override(language):
                    url = reverse(view_identifier, kwargs={'slug': slug})

            # Page is a not-supported apphook
            else:
                continue

            context.get('alternatives').append({
                'language': language,
                'url': url
            })

        except Exception as e:
            logger.error('Error getting alternative languages of the page {}.\n{}'.format(
                request.path_info,
                traceback.format_stack(),
            ))

    return context