Is there a generic way to create an URL template in Django?

Question

I'm looking for an easy way to compose URLs in the frontend with JavaScript. Let's take the URL patterns from the Django tutorial as an example:

urlpatterns = [
    # ex: /polls/
    url(r'^$', views.index, name='index'),
    # ex: /polls/5/
    url(r'^(?P<question_id>[0-9]+)/$', views.detail, name='detail'),
    # ex: /polls/5/results/
    url(r'^(?P<question_id>[0-9]+)/results/$', views.results, name='results'),
    # ex: /polls/5/vote/
    url(r'^(?P<question_id>[0-9]+)/vote/$', views.vote, name='vote'),
]

I'd like to create a template from an URL name reference (I'm using MustacheJS in the example, but I'm not fixed on any particular syntax):

assert get_url_template('detail') == "/polls/{{ question_id }}/"
assert get_url_template('results') == "/polls/{{ question_id }}/results/"

In the frontend, I would simple supply question_id and get a complete URL. Of course, this has to work for most if not all URL patterns.

Is there any easy way to do this or do I have to hack something together based on Django's urlresolver?

Answer 1

I've managed to hack something simple which does what I wanted, maybe it'll be useful for someone. It's a template tag which replaces named groups with {{ name }} sequences and takes the URL name as a single parameter.

import re

from django import template
from django.core.urlresolvers import get_resolver, get_urlconf   

register = template.Library()

@register.simple_tag
def data_url(urlname):

    urlconf = get_urlconf()
    resolver = get_resolver(urlconf)

    if urlname not in resolver.reverse_dict:
        return ""

    url = resolver.reverse_dict[urlname][0][-1][0]
    url = re.sub(r'%\((.*?)\)s', '{{ \g<1> }}', url)

    return "/%s" % url

Answer 2

There are a bunch of JS libraries which will do this. A quick google showed up django-js-reverse which looks quite nice, but has some open issues which are worth a look. You could always fork and fix, or at the least see how they do it.

[EDIT] Alternatively, if you want to avoid the ajax route, you could write a Django inclusion tag which (somehow - TBC) imports the urlconf and renders a template which lays out the url syntax for each in a JS data structure, wrapped in a block, so that they're all loaded into the template and available. It's not a particularly pretty solution, though...