Flask Session Management
Revision as of 19:47, 8 July 2014 by PeterHarding (talk | contribs)
Also see - Flask Stuff
- https://stormpath.com/blog/part-two-solving-flask-authentication-problem/
- http://flask.pocoo.org/docs/appcontext/
Server Side Session with Redis
import pickle from datetime import timedelta from uuid import uuid4 from redis import Redis from werkzeug.datastructures import CallbackDict from flask.sessions import SessionInterface, SessionMixin class RedisSession(CallbackDict, SessionMixin): def __init__(self, initial=None, sid=None, new=False): def on_update(self): self.modified = True CallbackDict.__init__(self, initial, on_update) self.sid = sid self.new = new self.modified = False class RedisSessionInterface(SessionInterface): serializer = pickle session_class = RedisSession def __init__(self, redis=None, prefix='session:'): if redis is None: redis = Redis() self.redis = redis self.prefix = prefix def generate_sid(self): return str(uuid4()) def get_redis_expiration_time(self, app, session): if session.permanent: return app.permanent_session_lifetime return timedelta(days=1) def open_session(self, app, request): sid = request.cookies.get(app.session_cookie_name) if not sid: sid = self.generate_sid() return self.session_class(sid=sid, new=True) val = self.redis.get(self.prefix + sid) if val is not None: data = self.serializer.loads(val) return self.session_class(data, sid=sid) return self.session_class(sid=sid, new=True) def save_session(self, app, session, response): domain = self.get_cookie_domain(app) if not session: self.redis.delete(self.prefix + session.sid) if session.modified: response.delete_cookie(app.session_cookie_name, domain=domain) return redis_exp = self.get_redis_expiration_time(app, session) cookie_exp = self.get_expiration_time(app, session) val = self.serializer.dumps(dict(session)) self.redis.setex(self.prefix + session.sid, val, int(redis_exp.total_seconds())) response.set_cookie(app.session_cookie_name, session.sid, expires=cookie_exp, httponly=True, domain=domain)
Here is how to enable it:
app = Flask(__name__) app.session_interface = RedisSessionInterface()
If you get an attribute error that total_seconds is missing it means you're using a version of Python older than 2.7. In this case you can use this function as a replacement for the total_seconds method:
def total_seconds(td): return td.days * 60 * 60 * 24 + td.seconds