Django user timezones

middleware.py

from django.conf import settings
from django.utils import timezone
import pygeoip
import pytz

db_loaded = False
db = None


def load_db():
    global db, db_loaded
    db = pygeoip.GeoIP(settings.GEOIP_DATABASE, pygeoip.MEMORY_CACHE)
    db_loaded = True


def get_client_ip(request):
    return request.META.get('REMOTE_ADDR')


class TimezoneMiddleware(object):
    def process_request(self, request):
        if request.user and request.user.is_authenticated() and \
                request.user.timezone in pytz.all_timezones:
            tzname = request.user.timezone
        else:
            if not db_loaded:
                load_db()

            tzname = db.time_zone_by_addr(get_client_ip(request))

        if not tzname in pytz.all_timezones:
            tzname = timezone.get_default_timezone()

        timezone.activate(tzname)
        request.timezone = tzname

    def process_response(self, request, response):
        timezone.deactivate()
        return response