# -*- coding: utf-8 -*- """ webapp2_extras.appengine.sessions_ndb ===================================== Extended sessions stored in datastore using the ndb library. :copyright: 2011 by tipfy.org. :license: Apache Sotware License, see LICENSE for details. """ from __future__ import absolute_import import pickle from google.appengine.api import datastore_errors from google.appengine.api import memcache from ndb import model from webapp2_extras import sessions class PickledProperty(model.BlobProperty): _type = None _indexed = False def __init__(self, _type, *args, **kwargs): super(PickledProperty, self).__init__(*args, **kwargs) self._type = _type def _validate_type(self, value): if not isinstance(value, self._type): raise datastore_errors.BadValueError( 'Expected %r, got %r' % (self._type, value)) return value def _validate(self, value): return self._validate_type(value) def _db_set_value(self, v, p, value): value = self._validate_type(value) super(PickledProperty, self)._db_set_value(v, p, pickle.dumps(value)) def _db_get_value(self, v, p): if not v.has_stringvalue(): return None return pickle.loads(v.stringvalue()) class Session(model.Model): """A model to store session data.""" #: Save time. updated = model.DateTimeProperty(auto_now=True) #: Session data, pickled. data = PickledProperty(dict) @classmethod def get_by_sid(cls, sid): """Returns a ``Session`` instance by session id. :param sid: A session id. :returns: An existing ``Session`` entity. """ data = memcache.get(sid) if not data: session = model.Key(cls, sid).get() if session: data = session.data memcache.set(sid, data) return data def _put(self): """Saves the session and updates the memcache entry.""" memcache.set(self._key.id(), self.data) super(Session, self).put() class DatastoreSessionFactory(sessions.CustomBackendSessionFactory): """A session factory that stores data serialized in datastore. To use datastore sessions, pass this class as the `factory` keyword to :meth:`webapp2_extras.sessions.SessionStore.get_session`:: from webapp2_extras import sessions_ndb # [...] session = self.session_store.get_session( name='db_session', factory=sessions_ndb.DatastoreSessionFactory) See in :meth:`webapp2_extras.sessions.SessionStore` an example of how to make sessions available in a :class:`webapp2.RequestHandler`. """ #: The session model class. session_model = Session def _get_by_sid(self, sid): """Returns a session given a session id.""" if self._is_valid_sid(sid): data = self.session_model.get_by_sid(sid) if data is not None: self.sid = sid return sessions.SessionDict(self, data=data) self.sid = self._get_new_sid() return sessions.SessionDict(self, new=True) def save_session(self, response): if self.session is None or not self.session.modified: return self.session_model(id=self.sid, data=dict(self.session))._put() self.session_store.save_secure_cookie( response, self.name, {'_sid': self.sid}, **self.session_args)