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287 lines
9.0 KiB
287 lines
9.0 KiB
import base64 |
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import os |
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import random |
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import sys |
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import time |
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from datetime import datetime, timedelta |
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try: |
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import cPickle as pickle |
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except ImportError: |
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import pickle |
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from django.conf import settings |
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from django.core.exceptions import SuspiciousOperation |
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from django.utils.hashcompat import md5_constructor |
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|
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# Use the system (hardware-based) random number generator if it exists. |
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if hasattr(random, 'SystemRandom'): |
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randrange = random.SystemRandom().randrange |
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else: |
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randrange = random.randrange |
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MAX_SESSION_KEY = 18446744073709551616L # 2 << 63 |
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|
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class CreateError(Exception): |
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""" |
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Used internally as a consistent exception type to catch from save (see the |
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docstring for SessionBase.save() for details). |
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""" |
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pass |
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|
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class SessionBase(object): |
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""" |
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Base class for all Session classes. |
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""" |
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TEST_COOKIE_NAME = 'testcookie' |
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TEST_COOKIE_VALUE = 'worked' |
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def __init__(self, session_key=None): |
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self._session_key = session_key |
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self.accessed = False |
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self.modified = False |
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def __contains__(self, key): |
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return key in self._session |
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def __getitem__(self, key): |
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return self._session[key] |
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def __setitem__(self, key, value): |
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self._session[key] = value |
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self.modified = True |
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def __delitem__(self, key): |
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del self._session[key] |
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self.modified = True |
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def keys(self): |
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return self._session.keys() |
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def items(self): |
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return self._session.items() |
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def get(self, key, default=None): |
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return self._session.get(key, default) |
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def pop(self, key, *args): |
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self.modified = self.modified or key in self._session |
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return self._session.pop(key, *args) |
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def setdefault(self, key, value): |
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if key in self._session: |
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return self._session[key] |
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else: |
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self.modified = True |
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self._session[key] = value |
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return value |
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def set_test_cookie(self): |
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self[self.TEST_COOKIE_NAME] = self.TEST_COOKIE_VALUE |
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def test_cookie_worked(self): |
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return self.get(self.TEST_COOKIE_NAME) == self.TEST_COOKIE_VALUE |
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def delete_test_cookie(self): |
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del self[self.TEST_COOKIE_NAME] |
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def encode(self, session_dict): |
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"Returns the given session dictionary pickled and encoded as a string." |
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pickled = pickle.dumps(session_dict, pickle.HIGHEST_PROTOCOL) |
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pickled_md5 = md5_constructor(pickled + settings.SECRET_KEY).hexdigest() |
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return base64.encodestring(pickled + pickled_md5) |
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def decode(self, session_data): |
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encoded_data = base64.decodestring(session_data) |
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pickled, tamper_check = encoded_data[:-32], encoded_data[-32:] |
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if md5_constructor(pickled + settings.SECRET_KEY).hexdigest() != tamper_check: |
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raise SuspiciousOperation("User tampered with session cookie.") |
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try: |
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return pickle.loads(pickled) |
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# Unpickling can cause a variety of exceptions. If something happens, |
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# just return an empty dictionary (an empty session). |
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except: |
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return {} |
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def update(self, dict_): |
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self._session.update(dict_) |
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self.modified = True |
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def has_key(self, key): |
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return self._session.has_key(key) |
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def values(self): |
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return self._session.values() |
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def iterkeys(self): |
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return self._session.iterkeys() |
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def itervalues(self): |
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return self._session.itervalues() |
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def iteritems(self): |
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return self._session.iteritems() |
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def clear(self): |
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# To avoid unnecessary persistent storage accesses, we set up the |
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# internals directly (loading data wastes time, since we are going to |
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# set it to an empty dict anyway). |
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self._session_cache = {} |
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self.accessed = True |
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self.modified = True |
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def _get_new_session_key(self): |
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"Returns session key that isn't being used." |
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# The random module is seeded when this Apache child is created. |
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# Use settings.SECRET_KEY as added salt. |
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try: |
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pid = os.getpid() |
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except AttributeError: |
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# No getpid() in Jython, for example |
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pid = 1 |
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while 1: |
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session_key = md5_constructor("%s%s%s%s" |
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% (randrange(0, MAX_SESSION_KEY), pid, time.time(), |
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settings.SECRET_KEY)).hexdigest() |
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if not self.exists(session_key): |
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break |
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return session_key |
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def _get_session_key(self): |
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if self._session_key: |
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return self._session_key |
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else: |
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self._session_key = self._get_new_session_key() |
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return self._session_key |
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def _set_session_key(self, session_key): |
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self._session_key = session_key |
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session_key = property(_get_session_key, _set_session_key) |
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def _get_session(self, no_load=False): |
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""" |
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Lazily loads session from storage (unless "no_load" is True, when only |
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an empty dict is stored) and stores it in the current instance. |
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""" |
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self.accessed = True |
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try: |
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return self._session_cache |
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except AttributeError: |
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if self._session_key is None or no_load: |
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self._session_cache = {} |
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else: |
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self._session_cache = self.load() |
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return self._session_cache |
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_session = property(_get_session) |
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def get_expiry_age(self): |
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"""Get the number of seconds until the session expires.""" |
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expiry = self.get('_session_expiry') |
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if not expiry: # Checks both None and 0 cases |
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return settings.SESSION_COOKIE_AGE |
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if not isinstance(expiry, datetime): |
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return expiry |
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delta = expiry - datetime.now() |
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return delta.days * 86400 + delta.seconds |
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def get_expiry_date(self): |
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"""Get session the expiry date (as a datetime object).""" |
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expiry = self.get('_session_expiry') |
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if isinstance(expiry, datetime): |
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return expiry |
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if not expiry: # Checks both None and 0 cases |
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expiry = settings.SESSION_COOKIE_AGE |
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return datetime.now() + timedelta(seconds=expiry) |
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def set_expiry(self, value): |
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""" |
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Sets a custom expiration for the session. ``value`` can be an integer, |
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a Python ``datetime`` or ``timedelta`` object or ``None``. |
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If ``value`` is an integer, the session will expire after that many |
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seconds of inactivity. If set to ``0`` then the session will expire on |
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browser close. |
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If ``value`` is a ``datetime`` or ``timedelta`` object, the session |
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will expire at that specific future time. |
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If ``value`` is ``None``, the session uses the global session expiry |
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policy. |
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""" |
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if value is None: |
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# Remove any custom expiration for this session. |
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try: |
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del self['_session_expiry'] |
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except KeyError: |
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pass |
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return |
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if isinstance(value, timedelta): |
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value = datetime.now() + value |
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self['_session_expiry'] = value |
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def get_expire_at_browser_close(self): |
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""" |
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Returns ``True`` if the session is set to expire when the browser |
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closes, and ``False`` if there's an expiry date. Use |
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``get_expiry_date()`` or ``get_expiry_age()`` to find the actual expiry |
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date/age, if there is one. |
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""" |
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if self.get('_session_expiry') is None: |
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return settings.SESSION_EXPIRE_AT_BROWSER_CLOSE |
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return self.get('_session_expiry') == 0 |
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def flush(self): |
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""" |
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Removes the current session data from the database and regenerates the |
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key. |
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""" |
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self.clear() |
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self.delete() |
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self.create() |
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def cycle_key(self): |
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""" |
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Creates a new session key, whilst retaining the current session data. |
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""" |
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data = self._session_cache |
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key = self.session_key |
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self.create() |
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self._session_cache = data |
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self.delete(key) |
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# Methods that child classes must implement. |
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def exists(self, session_key): |
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""" |
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Returns True if the given session_key already exists. |
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""" |
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raise NotImplementedError |
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def create(self): |
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""" |
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Creates a new session instance. Guaranteed to create a new object with |
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a unique key and will have saved the result once (with empty data) |
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before the method returns. |
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""" |
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raise NotImplementedError |
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def save(self, must_create=False): |
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""" |
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Saves the session data. If 'must_create' is True, a new session object |
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is created (otherwise a CreateError exception is raised). Otherwise, |
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save() can update an existing object with the same key. |
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""" |
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raise NotImplementedError |
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def delete(self, session_key=None): |
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""" |
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Deletes the session data under this key. If the key is None, the |
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current session key value is used. |
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""" |
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raise NotImplementedError |
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def load(self): |
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""" |
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Loads the session data and returns a dictionary. |
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""" |
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raise NotImplementedError
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