--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/app/django/contrib/sessions/backends/base.py	Fri Jul 18 18:22:23 2008 +0000
@@ -0,0 +1,155 @@
+import base64
+import md5
+import os
+import random
+import sys
+import time
+from django.conf import settings
+from django.core.exceptions import SuspiciousOperation
+
+try:
+    import cPickle as pickle
+except ImportError:
+    import pickle
+
+class SessionBase(object):
+    """
+    Base class for all Session classes.
+    """
+    TEST_COOKIE_NAME = 'testcookie'
+    TEST_COOKIE_VALUE = 'worked'
+
+    def __init__(self, session_key=None):
+        self._session_key = session_key
+        self.accessed = False
+        self.modified = False
+
+    def __contains__(self, key):
+        return key in self._session
+
+    def __getitem__(self, key):
+        return self._session[key]
+
+    def __setitem__(self, key, value):
+        self._session[key] = value
+        self.modified = True
+
+    def __delitem__(self, key):
+        del self._session[key]
+        self.modified = True
+
+    def keys(self):
+        return self._session.keys()
+
+    def items(self):
+        return self._session.items()
+
+    def get(self, key, default=None):
+        return self._session.get(key, default)
+
+    def pop(self, key, *args):
+        self.modified = self.modified or key in self._session
+        return self._session.pop(key, *args)
+
+    def setdefault(self, key, value):
+        if key in self._session:
+            return self._session[key]
+        else:
+            self.modified = True
+            self._session[key] = value
+            return value
+
+    def set_test_cookie(self):
+        self[self.TEST_COOKIE_NAME] = self.TEST_COOKIE_VALUE
+
+    def test_cookie_worked(self):
+        return self.get(self.TEST_COOKIE_NAME) == self.TEST_COOKIE_VALUE
+
+    def delete_test_cookie(self):
+        del self[self.TEST_COOKIE_NAME]
+
+    def encode(self, session_dict):
+        "Returns the given session dictionary pickled and encoded as a string."
+        pickled = pickle.dumps(session_dict, pickle.HIGHEST_PROTOCOL)
+        pickled_md5 = md5.new(pickled + settings.SECRET_KEY).hexdigest()
+        return base64.encodestring(pickled + pickled_md5)
+
+    def decode(self, session_data):
+        encoded_data = base64.decodestring(session_data)
+        pickled, tamper_check = encoded_data[:-32], encoded_data[-32:]
+        if md5.new(pickled + settings.SECRET_KEY).hexdigest() != tamper_check:
+            raise SuspiciousOperation("User tampered with session cookie.")
+        try:
+            return pickle.loads(pickled)
+        # Unpickling can cause a variety of exceptions. If something happens,
+        # just return an empty dictionary (an empty session).
+        except:
+            return {}
+
+    def _get_new_session_key(self):
+        "Returns session key that isn't being used."
+        # The random module is seeded when this Apache child is created.
+        # Use settings.SECRET_KEY as added salt.
+        try:
+            pid = os.getpid()
+        except AttributeError:
+            # No getpid() in Jython, for example
+            pid = 1
+        while 1:
+            session_key = md5.new("%s%s%s%s" % (random.randint(0, sys.maxint - 1),
+                                  pid, time.time(), settings.SECRET_KEY)).hexdigest()
+            if not self.exists(session_key):
+                break
+        return session_key
+
+    def _get_session_key(self):
+        if self._session_key:
+            return self._session_key
+        else:
+            self._session_key = self._get_new_session_key()
+            return self._session_key
+
+    def _set_session_key(self, session_key):
+        self._session_key = session_key
+
+    session_key = property(_get_session_key, _set_session_key)
+
+    def _get_session(self):
+        # Lazily loads session from storage.
+        self.accessed = True
+        try:
+            return self._session_cache
+        except AttributeError:
+            if self._session_key is None:
+                self._session_cache = {}
+            else:
+                self._session_cache = self.load()
+        return self._session_cache
+
+    _session = property(_get_session)
+
+    # Methods that child classes must implement.
+
+    def exists(self, session_key):
+        """
+        Returns True if the given session_key already exists.
+        """
+        raise NotImplementedError
+
+    def save(self):
+        """
+        Saves the session data.
+        """
+        raise NotImplementedError
+
+    def delete(self, session_key):
+        """
+        Clears out the session data under this key.
+        """
+        raise NotImplementedError
+
+    def load(self):
+        """
+        Loads the session data and returns a dictionary.
+        """
+        raise NotImplementedError