[patch] allow middleware to override the URL configuration

[Fredrik Lundh <fredrik@…>]

Here's a simple patch that lets you use different URL configurations for each request. This allows you to use middleware components to switch between different configurations based on hostname:

​http://effbot.org/zone/django-multihost.htm

or otherwise provide different views of the site, based on some characteristic of the request.

[Fredrik Lundh <fredrik@…>]

(adding an urlconf class attribute to the Request base class would also be a good idea, of course)

[Jacob]

(In [4237]) Fixed #3187 -- Django will now look for the root URLconf as an attribute of the request object, if available. This lets middleware override the urlconf as needed. Thanks, Fredrik Lundh.