from django.contrib.sessions.backends.base import SessionBase from django.core import signing class SessionStore(SessionBase): def load(self): """ Load the data from the key itself instead of fetching from some external data store. Opposite of _get_session_key(), raise BadSignature if signature fails. """ try: return signing.loads( self.session_key, serializer=self.serializer, # This doesn't handle non-default expiry dates, see #19201 max_age=self.get_session_cookie_age(), salt='django.contrib.sessions.backends.signed_cookies', ) except Exception: # BadSignature, ValueError, or unpickling exceptions. If any of # these happen, reset the session. self.create() return {} def create(self): """ To create a new key, set the modified flag so that the cookie is set on the client for the current request. """ self.modified = True def save(self, must_create=False): """ To save, get the session key as a securely signed string and then set the modified flag so that the cookie is set on the client for the current request. """ self._session_key = self._get_session_key() self.modified = True def exists(self, session_key=None): """ This method makes sense when you're talking to a shared resource, but it doesn't matter when you're storing the information in the client's cookie. """ return False def delete(self, session_key=None): """ To delete, clear the session key and the underlying data structure and set the modified flag so that the cookie is set on the client for the current request. """ self._session_key = '' self._session_cache = {} self.modified = True def cycle_key(self): """ Keep the same data but with a new key. Call save() and it will automatically save a cookie with a new key at the end of the request. """ self.save() def _get_session_key(self): """ Instead of generating a random string, generate a secure url-safe base64-encoded string of data as our session key. """ return signing.dumps( self._session, compress=True, salt='django.contrib.sessions.backends.signed_cookies', serializer=self.serializer, ) @classmethod def clear_expired(cls): pass