tornado session 和 flash 实现，参考了 https://gist.github.com/ayang/1735032

base.py

# -*-coding:utf-8-*-

import tornado.web
from frame.region import region
from frame.region import Session
from frame.region import Flash
import services.user


class BaseRequestHandler(tornado.web.RequestHandler):
    # 这个函数的返回值，会体现在模板的 current_user 中
    def get_current_user(self):
        uid = self.session['uid']
        return services.user.find_by_id(uid) if uid else None

    def logout(self):
        self.session.clear()

    def __init__(self, *argc, **argkw):
        super(BaseRequestHandler, self).__init__(*argc, **argkw)
        self.region = region
        self.request.flash = self.flash.get()

    @property
    def session(self):
        session_id = self.get_secure_cookie('sid')
        session = Session(session_id)
        if not session_id:
            self.set_secure_cookie('sid', session.session_id)
        return session

    @property
    def flash(self):
        return Flash(self.session)

region.py

# -*-coding:utf-8-*-

from uuid import uuid4
from dogpile.cache import make_region
import config


region = make_region(
    key_mangler=lambda key: 'ncms:tornado:' + key
).configure(
    'dogpile.cache.redis',
    arguments={
        'host': config.redis['host'],
        'port': config.redis['port'],
        'db': config.redis['db'],
        'distributed_lock': True
    }
)


class Session(object):
    # 缓存池，主要用于：
    # A 页面 redict 到 B 页面，B 的 __init__ 比 A 的 __del__ 先执行，造成 session 数据不同步
    pool = {}

    def __init__(self, session_id=None):
        self._session_id = session_id if session_id else uuid4().get_hex()

        # 先从 redis 中读取，再从类池中读取，最后再新建
        session_data = region.get(self._session_id)
        if not session_data and self._session_id in Session.pool:
            session_data = Session.pool[self._session_id]
        self._session_data = session_data if session_data else dict()
        Session.pool[self._session_id] = self._session_data
        self.dirty = False

    def clear(self):
        region.delete(self._session_id)

    @property
    def session_id(self):
        return self._session_id

    def clear(self, key=None):
        if key:
            if key in self._session_data:
                self.__delitem__(key)
            return

        region.delete(self._session_id)
        if self._session_id in Session.pool:
            del Session.pool[self._session_id]
        self._session_data = dict()
        Session.pool[self._session_id] = self._session_data

    def __getitem__(self, key):
        if key in self._session_data:
            return self._session_data[key]

    def __setitem__(self, key, value):
        self._session_data[key] = value
        self._dirty()

    def __delitem__(self, key):
        if key in self._session_data:
            del self._session_data[key]
        self._dirty()

    def __len__(self):
        return len(self._session_data)

    def __contains__(self, key):
        return key in self._session_data

    def __iter__(self):
        for key in self._session_data:
            yield key

    def __repr__(self):
        return self._session_data.__repr__()

    def __del__(self):
        if self.dirty:
            self._save()
        if self._session_id in Session.pool:
            del Session.pool[self._session_id]

    def _dirty(self):
        self.dirty = True

    def _save(self):
        region.set(self._session_id, self._session_data)
        self.dirty = False


class Flash:
    def __init__(self, session):
        self.session = session

    def set(self, key, value):
        data = self.session['ncms.flash.data']
        data = data if data else dict()
        data[key] = value
        self.session['ncms.flash.data'] = data

    def get(self):
        data = self.session['ncms.flash.data']
        self.session.clear('ncms.flash.data')
        return data if data else dict()