57 lines
1.6 KiB
Python
57 lines
1.6 KiB
Python
"Base Cache class."
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from django.core.exceptions import ImproperlyConfigured
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class InvalidCacheBackendError(ImproperlyConfigured):
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pass
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class BaseCache(object):
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def __init__(self, params):
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timeout = params.get('timeout', 300)
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try:
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timeout = int(timeout)
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except (ValueError, TypeError):
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timeout = 300
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self.default_timeout = timeout
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def get(self, key, default=None):
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"""
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Fetch a given key from the cache. If the key does not exist, return
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default, which itself defaults to None.
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"""
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raise NotImplementedError
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def set(self, key, value, timeout=None):
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"""
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Set a value in the cache. If timeout is given, that timeout will be
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used for the key; otherwise the default cache timeout will be used.
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"""
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raise NotImplementedError
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def delete(self, key):
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"""
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Delete a key from the cache, failing silently.
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"""
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raise NotImplementedError
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def get_many(self, keys):
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"""
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Fetch a bunch of keys from the cache. For certain backends (memcached,
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pgsql) this can be *much* faster when fetching multiple values.
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Returns a dict mapping each key in keys to its value. If the given
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key is missing, it will be missing from the response dict.
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"""
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d = {}
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for k in keys:
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val = self.get(k)
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if val is not None:
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d[k] = val
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return d
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def has_key(self, key):
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"""
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Returns True if the key is in the cache and has not expired.
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"""
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return self.get(key) is not None
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