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"File-based cache backend"
from django.core.cache.backends.simple import CacheClass as SimpleCacheClass
import os, time, urllib
try:
import cPickle as pickle
except ImportError:
import pickle
class CacheClass(SimpleCacheClass):
def __init__(self, dir, params):
self._dir = dir
if not os.path.exists(self._dir):
self._createdir()
SimpleCacheClass.__init__(self, dir, params)
del self._cache
del self._expire_info
def get(self, key, default=None):
fname = self._key_to_file(key)
try:
f = open(fname, 'rb')
exp = pickle.load(f)
now = time.time()
if exp < now:
f.close()
os.remove(fname)
else:
return pickle.load(f)
except (IOError, OSError, EOFError, pickle.PickleError):
pass
return default
def set(self, key, value, timeout=None):
fname = self._key_to_file(key)
if timeout is None:
timeout = self.default_timeout
try:
filelist = os.listdir(self._dir)
except (IOError, OSError):
self._createdir()
filelist = []
if len(filelist) > self._max_entries:
self._cull(filelist)
try:
f = open(fname, 'wb')
now = time.time()
pickle.dump(now + timeout, f, 2)
pickle.dump(value, f, 2)
except (IOError, OSError):
pass
def delete(self, key):
try:
os.remove(self._key_to_file(key))
except (IOError, OSError):
pass
def has_key(self, key):
return os.path.exists(self._key_to_file(key))
def _cull(self, filelist):
if self._cull_frequency == 0:
doomed = filelist
else:
doomed = [k for (i, k) in enumerate(filelist) if i % self._cull_frequency == 0]
for fname in doomed:
try:
os.remove(os.path.join(self._dir, fname))
except (IOError, OSError):
pass
def _createdir(self):
try:
os.makedirs(self._dir)
except OSError:
raise EnvironmentError, "Cache directory '%s' does not exist and could not be created'" % self._dir
def _key_to_file(self, key):
return os.path.join(self._dir, urllib.quote_plus(key))
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