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56 lines
1.8 KiB
56 lines
1.8 KiB
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.get(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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