Session imitation tornado + mongo

gistfile1.py

#!/usr/bin/env python
# coding: utf-8

import mongoengine as me

from uuid import uuid4
from datetime import datetime

class Session(me.Document):
    meta = {'collection': 'sessions'}
    
    session_id = me.StringField(default = '%s' % uuid4())
    user = me.ReferenceField("User")
    cart = me.ReferenceField("Cart")

    def __repr__(self):
        return "<Session: [%s] [%s] [%s]>" % (self.session_id, self.user, self.cart)

    def __str__(self):
        return repr(self)

    @classmethod
    def get(cls, sid = None):
        if sid:
            session = cls.objects(session_id = sid)
            if not session:
                session = cls()
        else:
            session = cls()
        return session

from tornado.web import *
from tornado.ioloop import IOLoop

class BaseHandler(RequestHandler):
    SESSION_COOKIE = 'session_id'

    def update_cookie(self):
        sid = self.get_secure_cookie(self.SESSION_COOKIE)
        self.session = Session.get(sid)
        self.set_secure_cookie(self.SESSION_COOKIE, self.session.session_id)

    def get_current_user(self):
        self.update_cookie()
        return self.session.session_id


class Handle1(BaseHandler):
    @authenticated
    def get(self):
        self.write("Handle1")

class Handle2(BaseHandler):
    def get(self):
        self.write("Handle2")

class Handle3(BaseHandler):
    def get(self):
        self.update_cookie()
        self.write("Handle3")

if __name__ == '__main__':
    app = Application([
        (r'/1', Handle1),
        (r'/2', Handle2),
        (r'/3', Handle3),
        ], cookie_secret = '1234', login_url = '/2')
    app.listen(5000)

    IOLoop.instance().start()