Various programming stuff

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Show 404 page on django when DEBUG=True

The default 404 error page on django can be easily overriden by adding a template named 404.html to the top level directory of your templates. However, on your development environment you’ll never be able to see this template because when DEBUG=True django will render the debug not found page to help you debug your url configuration.

If you want to display that page in your development environment you can always change the DEBUG setting to False, however there’s a better way: Add a url pattern for django’s default 404 view - just add the following to your urls.py:

import django.views.defaults

urlpatterns = patterns('',
    # Other url patterns ...
    url(r'^404/$', django.views.defaults.page_not_found, ),

You’ll then be able to see your 404 page by visiting the defined URL!

Upgrade for newer Django versions

I’ve recently found out that for newer Django versions the page_not_found view needs a second parameter (beyond request) named exception (see here). Thus if you just add the view to your urls as I propose you’ll get an exception. To fix it, you can do something like:

import django

def custom_page_not_found(request):
    return django.views.defaults.page_not_found(request, None)

urlpatterns = [
    path("404/", custom_page_not_found),

This creates a simple view that calls the builtin page_not_found passing it None as the exception parameter.