maintenance mode middleware

middleware.py

from django import http
from mainsite import settings

class MaintenanceMiddleware(object):
    """Serve a temporary redirect to a maintenance url in maintenance mode"""
    def process_request(self, request):
        if getattr(settings, 'MAINTENANCE_MODE', False) == True and hasattr(settings, 'MAINTENANCE_URL'):
            return http.HttpResponseRedirect(settings.MAINTENANCE_URL)
        return None