Question

I just set up the django environment and as the tutorial said. I typed python manager.py runserver and it told me to open 127.0.0.1:8000. When I open it, it worked with the correct welcome page.

But here is my question: who generates this default welcome page? Since there is no views.py and the urls.py page is empty.

Answer 1

Take a look at django/core/handlers/base.py and django/views/debug.py. In a nutshell, if django gets a 404, which it will if you don’t have any routes set up, then in base.py

if settings.DEBUG:
    from django.views import debug
    response = debug.technical_404_response(request, e)

And in debug.py look at technical_404_response and empty_urlconf