gistfile1.py

import base64
try:
    import json
except ImportError:
    import simplejson as json

from django.contrib.sessions.backends.db import SessionStore as DBSessionStore


class SessionStore(DBSessionStore):
    def __init__(self, *args, **kwargs):
        super(SessionStore, self).__init__(*args, **kwargs)

    def encode(self, session_dict):
        "Returns the given session dictionary as json and encoded as a string."
        data = json.dumps(session_dict)
        hash = self._hash(data)
        return base64.encodestring(hash + "$" + data)

    def decode(self, session_data):
        encoded_data = base64.decodestring(session_data)
        try:
            # could produce ValueError if there is no ':'
            hash, data = encoded_data.split('$', 1)
            print(hash, data)
            expected_hash = self._hash(data)
            if not constant_time_compare(hash, expected_hash):
                raise SuspiciousOperation("Session data corrupted")
            else:
                return json.loads(data)
        except Exception:
            # ValueError, SuspiciousOperation, unpickling exceptions. If any of
            # these happen, just return an empty dictionary (an empty session).
            return {}