Skip sessions and user authentication middleware in Django (1.4).

middleware.py

from django.conf import settings
from django.core.handlers.base import BaseHandler
from django.core import urlresolvers


SILENT_EARLY_RETURN_FAIL = getattr(settings, 'SILENT_EARLY_RETURN_FAIL', True)

def return_early_decorator(view):
    """
    In a view, return early, like so:

        @return_early_decorator
        def view(request):
            # don't use request.user or request.session!
            return HttpResponse('A normal view!')

    """
    view.return_hella_early = True
    return view

class MaybeReturnEarlyView(object):
    def process_request(self, request):
        "Reuses code from BaseHandler's get_response."

        urlconf = settings.ROOT_URLCONF
        urlresolvers.set_urlconf(urlconf)
        resolver = urlresolvers.RegexURLResolver(r'^/', urlconf)

        if hasattr(request, 'urlconf'):
            # Reset url resolver with a custom urlconf.
            urlconf = request.urlconf
            urlresolvers.set_urlconf(urlconf)
            resolver = urlresolvers.RegexURLResolver(r'^/', urlconf)

        callback, callback_args, callback_kwargs = resolver.resolve(
                request.path_info)

        try:
            if getattr(callback, 'return_hella_early', False):
                handler = BaseHandler()
                handler._view_middleware = []
                handler._template_response_middleware = []
                handler._request_middleware = []
                handler._response_middleware = []
                handler._exception_middleware = []
                response = handler.get_response(request)
                response['X-Return-Early'] = 'true'
                return response
        except:
            if not SILENT_EARLY_RETURN_FAIL:
                raise
            pass # this lets the normal path go...

settings.py

MIDDLEWARE_CLASSES = (
    # etc...
    'django.middleware.common.CommonMiddleware',

    # place me *before* SessionMiddleware/AuthenticationMiddleware
    'path.to.middleware.MaybeReturnEarlyView',

    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    # etc...
)