57 lines
1.8 KiB
Python
57 lines
1.8 KiB
Python
from django.contrib.sessions.backends.base import SessionBase, CreateError
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from django.core.cache import cache
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class SessionStore(SessionBase):
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"""
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A cache-based session store.
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"""
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def __init__(self, session_key=None):
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self._cache = cache
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super(SessionStore, self).__init__(session_key)
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def load(self):
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session_data = self._cache.get(self.session_key)
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if session_data is not None:
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return session_data
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self.create()
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return {}
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def create(self):
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# Because a cache can fail silently (e.g. memcache), we don't know if
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# we are failing to create a new session because of a key collision or
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# because the cache is missing. So we try for a (large) number of times
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# and then raise an exception. That's the risk you shoulder if using
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# cache backing.
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for i in xrange(10000):
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self.session_key = self._get_new_session_key()
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try:
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self.save(must_create=True)
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except CreateError:
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continue
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self.modified = True
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return
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raise RuntimeError("Unable to create a new session key.")
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def save(self, must_create=False):
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if must_create:
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func = self._cache.add
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else:
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func = self._cache.set
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result = func(self.session_key, self._get_session(no_load=must_create),
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self.get_expiry_age())
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if must_create and not result:
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raise CreateError
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def exists(self, session_key):
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if self._cache.has_key(session_key):
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return True
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return False
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def delete(self, session_key=None):
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if session_key is None:
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if self._session_key is None:
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return
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session_key = self._session_key
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self._cache.delete(session_key)
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