wrw/session.py

   1 import threading, time, pickle, random, os
   2 import cookie
   3
   4 __all__ = ["db", "get"]
   5
   6 def hexencode(str):
   7     ret = ""
   8     for byte in str:
   9         ret += "%02X" % (ord(byte),)
  10     return ret
  11
  12 def gennonce(length):
  13     nonce = ""
  14     for i in xrange(length):
  15         nonce += chr(random.randint(0, 255))
  16     return nonce
  17
  18 class session(object):
  19     def __init__(self, expire = 86400 * 7):
  20         self.id = hexencode(gennonce(16))
  21         self.dict = {}
  22         self.lock = threading.Lock()
  23         self.ctime = self.atime = self.mtime = int(time.time())
  24         self.expire = expire
  25         self.dctl = set()
  26         self.dirtyp = False
  27
  28     def dirty(self):
  29         for d in self.dctl:
  30             if d.sessdirty():
  31                 return True
  32         return self.dirtyp
  33
  34     def frozen(self):
  35         for d in self.dctl:
  36             d.sessfrozen()
  37         self.dirtyp = False
  38
  39     def __getitem__(self, key):
  40         return self.dict[key]
  41
  42     def get(self, key, default = None):
  43         return self.dict.get(key, default)
  44
  45     def __setitem__(self, key, value):
  46         self.dict[key] = value
  47         if hasattr(value, "sessdirty"):
  48             self.dctl.add(value)
  49         else:
  50             self.dirtyp = True
  51
  52     def __delitem__(self, key):
  53         old = self.dict.pop(key)
  54         if old in self.dctl:
  55             self.dctl.remove(old)
  56         self.dirtyp = True
  57
  58     def __contains__(self, key):
  59         return key in self.dict
  60
  61     def __getstate__(self):
  62         ret = []
  63         for k, v in self.__dict__.items():
  64             if k == "lock": continue
  65             ret.append((k, v))
  66         return ret
  67
  68     def __setstate__(self, st):
  69         for k, v in st:
  70             self.__dict__[k] = v
  71         self.lock = threading.Lock()
  72
  73 class db(object):
  74     def __init__(self, cookiename = "wrwsess", path = "/"):
  75         self.live = {}
  76         self.cookiename = cookiename
  77         self.path = path
  78         self.lock = threading.Lock()
  79         self.cthread = None
  80         self.freezetime = 3600
  81
  82     def clean(self):
  83         now = int(time.time())
  84         with self.lock:
  85             dlist = []
  86             for sess in self.live.itervalues():
  87                 if sess.atime + self.freezetime < now:
  88                     try:
  89                         if sess.dirty():
  90                             self.freeze(sess)
  91                     except:
  92                         if sess.atime + sess.expire < now:
  93                             dlist.append(sess)
  94                     else:
  95                         dlist.append(sess)
  96             for sess in dlist:
  97                 del self.live[sess.id]
  98
  99     def cleanloop(self):
 100         try:
 101             while True:
 102                 time.sleep(300)
 103                 self.clean()
 104                 if len(self.live) == 0:
 105                     break
 106         finally:
 107             with self.lock:
 108                 self.cthread = None
 109
 110     def fetch(self, req):
 111         now = int(time.time())
 112         sessid = cookie.get(req, self.cookiename)
 113         new = False
 114         with self.lock:
 115             if self.cthread is None:
 116                 self.cthread = threading.Thread(target = self.cleanloop)
 117                 self.cthread.setDaemon(True)
 118                 self.cthread.start()
 119             try:
 120                 if sessid is None:
 121                     raise KeyError()
 122                 elif sessid in self.live:
 123                     sess = self.live[sessid]
 124                 else:
 125                     sess = self.thaw(sessid)
 126                     self.live[sessid] = sess
 127                 if sess.atime + sess.expire < now:
 128                     raise KeyError()
 129                 sess.atime = now
 130             except KeyError:
 131                 sess = session()
 132                 new = True
 133
 134         def ckfreeze(req):
 135             if sess.dirty():
 136                 if new:
 137                     cookie.add(req, self.cookiename, sess.id, self.path)
 138                     with self.lock:
 139                         self.live[sess.id] = sess
 140                 try:
 141                     self.freeze(sess)
 142                 except:
 143                     pass
 144         req.oncommit(ckfreeze)
 145         return sess
 146
 147     def thaw(self, sessid):
 148         raise KeyError()
 149
 150     def freeze(self, sess):
 151         raise TypeError()
 152
 153     def get(self, req):
 154         return req.item(self.fetch)
 155
 156 class backeddb(db):
 157     def __init__(self, backdb, *args, **kw):
 158         super(backeddb, self).__init__(*args, **kw)
 159         self.backdb = backdb
 160
 161     def thaw(self, sessid):
 162         data = self.backdb[sessid]
 163         try:
 164             return pickle.loads(data)
 165         except Exception, e:
 166             raise KeyError()
 167
 168     def freeze(self, sess):
 169         self.backdb[sess.id] = pickle.dumps(sess)
 170         sess.frozen()
 171
 172 class dirback(object):
 173     def __init__(self, path):
 174         self.path = path
 175
 176     def __getitem__(self, key):
 177         try:
 178             with open(os.path.join(self.path, key)) as inf:
 179                 return inf.read()
 180         except IOError:
 181             raise KeyError(key)
 182
 183     def __setitem__(self, key, value):
 184         if not os.path.exists(self.path):
 185             os.makedirs(self.path)
 186         with open(os.path.join(self.path, key), "w") as out:
 187             out.write(value)
 188
 189 default = backeddb(dirback(os.path.join("/tmp", "wrwsess-" + str(os.getuid()))))
 190
 191 def get(req):
 192     return default.get(req)