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         with self.lock:
 114             if self.cthread is None:
 115                 self.cthread = threading.Thread(target = self.cleanloop)
 116                 self.cthread.setDaemon(True)
 117                 self.cthread.start()
 118             try:
 119                 if sessid is None:
 120                     raise KeyError()
 121                 elif sessid in self.live:
 122                     sess = self.live[sessid]
 123                 else:
 124                     sess = self.thaw(sessid)
 125                     self.live[sessid] = sess
 126                 if sess.atime + sess.expire < now:
 127                     raise KeyError()
 128                 sess.atime = now
 129             except KeyError:
 130                 sess = session()
 131                 self.live[sess.id] = sess
 132                 sess.new = True
 133         req.oncommit(self.ckfreeze)
 134         return sess
 135
 136     def ckfreeze(self, req):
 137         sess = req.item(self.fetch)
 138         if sess.dirty():
 139             try:
 140                 if getattr(sess, "new", False):
 141                     cookie.add(req, self.cookiename, sess.id, self.path)
 142                     del sess.new
 143                 self.freeze(sess)
 144             except:
 145                 pass
 146
 147     def thaw(self, sessid):
 148         raise KeyError()
 149
 150     def freeze(self, sess):
 151         raise TypeError()
 152
 153 class backeddb(db):
 154     def __init__(self, backdb, *args, **kw):
 155         super(backeddb, self).__init__(*args, **kw)
 156         self.backdb = backdb
 157
 158     def thaw(self, sessid):
 159         data = self.backdb[sessid]
 160         try:
 161             return pickle.loads(data)
 162         except Exception, e:
 163             raise KeyError()
 164
 165     def freeze(self, sess):
 166         self.backdb[sess.id] = pickle.dumps(sess)
 167         sess.frozen()
 168
 169 class dirback(object):
 170     def __init__(self, path):
 171         self.path = path
 172
 173     def __getitem__(self, key):
 174         try:
 175             with open(os.path.join(self.path, key)) as inf:
 176                 return inf.read()
 177         except IOError:
 178             raise KeyError(key)
 179
 180     def __setitem__(self, key, value):
 181         if not os.path.exists(self.path):
 182             os.makedirs(self.path)
 183         with open(os.path.join(self.path, key), "w") as out:
 184             out.write(value)
 185
 186 default = backeddb(dirback(os.path.join("/tmp", "wrwsess-" + str(os.getuid()))))
 187
 188 def get(req):
 189     return req.item(default.fetch)