Deferred task using Flask's request context

deferred_flask.py

@login_manager.user_loader
def load_user(user_id):
    user = models.User.get_by_id(user_id)
    if user and not user.timezone:
        lat_long = request.headers.get('X-Appengine-Citylatlong', None)
        deferred.defer(set_user_timezone, user_id, lat_long)
    return user


def set_user_timezone(user_id, lat_long):
    with app.app_context():
        user = models.User.get_by_id(user_id)
        if user and not user.timezone:
            user.timezone = appengine_utils.user_timezone_from_latlong(lat_long).zone
            user.put()