ipsilon/util/sessions.py

   1 #!/usr/bin/python
   2 #
   3 # Copyright (C) 2014  Ipsilon project Contributors, for licensee see COPYING
   4
   5 import base64
   6 from cherrypy.lib.sessions import Session
   7 from ipsilon.util.data import SqlStore, SqlQuery
   8 import threading
   9 try:
  10     import cPickle as pickle
  11 except ImportError:
  12     import pickle
  13
  14
  15 SESSION_COLUMNS = ['id', 'data', 'expiration_time']
  16
  17
  18 class SqlSession(Session):
  19
  20     dburi = None
  21     _db = None
  22     _proto = 2
  23     locks = {}
  24
  25     @classmethod
  26     def setup(cls, **kwargs):
  27         """Initialization from cherrypy"""
  28
  29         for k, v in kwargs.items():
  30             if k == 'storage_dburi':
  31                 cls.dburi = v
  32
  33         cls._db = SqlStore(cls.dburi)
  34
  35     def _exists(self):
  36         q = SqlQuery(self._db, 'sessions', SESSION_COLUMNS)
  37         result = q.select({'id': self.id})
  38         return True if result.fetchone() else False
  39
  40     def _load(self):
  41         q = SqlQuery(self._db, 'sessions', SESSION_COLUMNS)
  42         result = q.select({'id': self.id})
  43         r = result.fetchone()
  44         if r:
  45             data = str(base64.b64decode(r[1]))
  46             return pickle.loads(data)
  47
  48     def _save(self, expiration_time):
  49         q = None
  50         try:
  51             q = SqlQuery(self._db, 'sessions', SESSION_COLUMNS, trans=True)
  52             q.delete({'id': self.id})
  53             data = pickle.dumps((self._data, expiration_time), self._proto)
  54             q.insert((self.id, base64.b64encode(data), expiration_time))
  55             q.commit()
  56         except Exception:  # pylint: disable=broad-except
  57             if q:
  58                 q.rollback()
  59             raise
  60
  61     def _delete(self):
  62         q = SqlQuery(self._db, 'sessions', SESSION_COLUMNS)
  63         q.delete({'id': self.id})
  64
  65     # copy what RamSession does for now
  66     def acquire_lock(self):
  67         """Acquire an exclusive lock on the currently-loaded session data."""
  68         self.locked = True
  69         self.locks.setdefault(self.id, threading.RLock()).acquire()
  70
  71     def release_lock(self):
  72         """Release the lock on the currently-loaded session data."""
  73         self.locks[self.id].release()
  74         self.locked = False