cdb9bc94d0
git-svn-id: svn://svn.cy55.de/Zope3/src/cybertools/trunk@3784 fd906abe-77d9-0310-91a1-e0d9ade77398
98 lines
2.5 KiB
Python
98 lines
2.5 KiB
Python
#
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# Copyright (c) 2010 Helmut Merz helmutm@cy55.de
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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"""
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A simple caching mechanism.
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$Id$
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"""
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from zope import component
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try:
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from lovely.memcached.interfaces import IMemcachedClient
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except ImportError:
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IMemcachedClient = None
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# internal implementation
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from cybertools.util.date import getTimeStamp
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INVALID = object()
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class CacheManager(dict):
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pass
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manager = CacheManager()
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class CacheItem(object):
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def __init__(self, identifier, value=INVALID, lifetime=3600):
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self.identifier = identifier
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self.lifetime = lifetime
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self.set(value)
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def set(self, value):
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self.value = value
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self.modified = getTimeStamp()
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def get(self):
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self.check()
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return self.value
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def check(self):
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if getTimeStamp() - self.modified > self.lifetime:
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self.value = INVALID
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def internalCache(getIdentifier, lifetime=3600):
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def _cache(fct):
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def __cache(*args, **kw):
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id = getIdentifier(*args, **kw)
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item = manager.setdefault(id, CacheItem(id, lifetime=lifetime))
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value = item.get()
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if value is INVALID:
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value = fct(*args, **kw)
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item.set(value)
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return value
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return __cache
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return _cache
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cache = internalCache
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# memcached implementation
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def mcCache(getIdentifier, lifetime=3600):
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def _cache(fct):
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def __cache(*args, **kw):
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id = getIdentifier(*args, **kw)
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client = component.getUtility(IMemcachedClient)
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value = client.query(id)
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if value is None:
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value = fct(*args, **kw)
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client.set(value, id, lifetime=lifetime)
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return value
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return __cache
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return _cache
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if IMemcachedClient is not None:
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cache = mcCache
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