How to generate urls in django

Question

In the django template language, you can use {% url [viewname] [args] %} to generate a url to a specific view with parameters. How can you programatically do the same in python code?

What I need is to create a list of menu items, each item has name, url, and active (whether it's the current page or not). This because it will be a lot cleaner to do this in python than the template language.

Answer 1

If you need to use something similar to the {% url %} template tag in your code, Django provides the django.core.urlresolvers.reverse(). The reverse() function has the following signature:

reverse(viewname, urlconf=None, args=None, kwargs=None)

http://www.djangoproject.com/documentation/url_dispatch/#utility-methods

Answer 2

I'm using two different approaches in my models.py. The first is the permalink decorator:

from django.db.models import permalink

def get_absolute_url(self): 
    """Construct the absolute URL for this Item."""
    return ('project.app.views.view_name', [str(self.id)])
get_absolute_url = permalink(get_absolute_url)

You can also call reverse directly:

from django.core.urlresolvers import reverse

def get_absolute_url(self): 
    """Construct the absolute URL for this Item."""
    return reverse('project.app.views.view_name', None, [str(self.id)])

Answer 3

Be aware that using reverse() requires that your urlconf module is 100% error free and can be processed - iow no ViewDoesNotExist errors or so, or you get the dreaded NoReverseMatch exception (errors in templates usually fail silently resulting in None).