sites.py 文件源码

def check_dependencies(self):
        """
        Check that all things needed to run the admin have been correctly installed.

        The default implementation checks that admin and contenttypes apps are
        installed, as well as the auth context processor.
        """
        if not apps.is_installed('django.contrib.admin'):
            raise ImproperlyConfigured(
                "Put 'django.contrib.admin' in your INSTALLED_APPS "
                "setting in order to use the admin application.")
        if not apps.is_installed('django.contrib.contenttypes'):
            raise ImproperlyConfigured(
                "Put 'django.contrib.contenttypes' in your INSTALLED_APPS "
                "setting in order to use the admin application.")
        try:
            default_template_engine = Engine.get_default()
        except Exception:
            # Skip this non-critical check:
            # 1. if the user has a non-trivial TEMPLATES setting and Django
            #    can't find a default template engine
            # 2. if anything goes wrong while loading template engines, in
            #    order to avoid raising an exception from a confusing location
            # Catching ImproperlyConfigured suffices for 1. but 2. requires
            # catching all exceptions.
            pass
        else:
            if ('django.contrib.auth.context_processors.auth'
                    not in default_template_engine.context_processors):
                raise ImproperlyConfigured(
                    "Enable 'django.contrib.auth.context_processors.auth' "
                    "in your TEMPLATES setting in order to use the admin "
                    "application.")