registering ModelAdmins with custom_admin_site does not show anything when split into multiple files

Question

I overwrote the admin site to customize a little bit on the main page of the admin and now get_urls is never called. Note, that I defined the

custom_admin.py:

class TestAdminSite(admin.AdminSite):
    index_template = "Test/admin_index.html"

    def index(self, request, extra_context=None):
        extra_context = extra_context or {}
        print("test")  # <-- this gets printed!
        return super().index(request, extra_context)

    def get_urls(self):
        urls = super().get_urls()
        print("test 2") # <-- not printed
        return urls

custom_admin_site = TestAdminSite(name="custom_admin")

admin.py:

from .custom_admin import custom_admin_site

in the projects urls.py I did:

from testapp.admin import custom_admin_site

urlpatterns = [..., path("admin/", custom_admin_site.urls), ... ]

but as commented above, get_urls is never called. why?

Answer 1

This is probably because the URL resolver loads lazily. Indeed, as long as you don't make a request, or you don't have an app that for example loads the URL resolver, it will not inspect the paths, and thus not call .get_urls() since the root urls.py is not read, and thus all consequent paths.

If you thus want to urls to be loaded, you need to somehow force the resolver to get loaded. The easiest way is probably to make a HTTP request. If you want to run this in a test, that is of course not always an option. You can force loading the resolver with:

from django.urls import get_resolver

get_resolver()