views.defaults.page_not_found()

defaults.page_not_found(request, exception, template_name='404.html')

When you raise Http404 from within a view, Django loads a special view devoted to handling 404 errors. By default, it’s the view django.views.defaults.page_not_found(), which either produces a very simple “Not Found” message or loads and renders the template 404.html if you created it in your root template directory.

The default 404 view will pass two variables to the template: request_path, which is the URL that resulted in the error, and exception, which is a useful representation of the exception that triggered the view (e.g. containing any message passed to a specific Http404 instance).

Three things to note about 404 views:

• The 404 view is also called if Django doesn’t find a match after checking every regular expression in the URLconf.
• The 404 view is passed a RequestContext and will have access to variables supplied by your template context processors (e.g. MEDIA_URL).
• If DEBUG is set to True (in your settings module), then your 404 view will never be used, and your URLconf will be displayed instead, with some debug information.