85 lines
3.0 KiB
Python
85 lines
3.0 KiB
Python
"""
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Caching framework.
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This package defines set of cache backends that all conform to a simple API.
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In a nutshell, a cache is a set of values -- which can be any object that
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may be pickled -- identified by string keys. For the complete API, see
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the abstract BaseCache class in django.core.cache.backends.base.
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Client code should not access a cache backend directly; instead it should
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either use the "cache" variable made available here, or it should use the
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get_cache() function made available here. get_cache() takes a CACHES alias or a
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backend path and config parameters, and returns an instance of a backend cache
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class.
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See docs/topics/cache.txt for information on the public API.
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"""
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import importlib
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from django.conf import settings
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from django.core import signals
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from django.core.cache.backends.base import (
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InvalidCacheBackendError, CacheKeyWarning, BaseCache)
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from django.core.exceptions import ImproperlyConfigured
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from django.utils.module_loading import import_by_path
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from django.utils.six.moves.urllib.parse import parse_qsl
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__all__ = [
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'get_cache', 'cache', 'DEFAULT_CACHE_ALIAS'
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]
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DEFAULT_CACHE_ALIAS = 'default'
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if DEFAULT_CACHE_ALIAS not in settings.CACHES:
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raise ImproperlyConfigured("You must define a '%s' cache" % DEFAULT_CACHE_ALIAS)
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def get_cache(backend, **kwargs):
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"""
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Function to load a cache backend dynamically. This is flexible by design
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to allow different use cases:
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To load a backend that is pre-defined in the settings::
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cache = get_cache('default')
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To load a backend with its dotted import path,
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including arbitrary options::
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cache = get_cache('django.core.cache.backends.memcached.MemcachedCache', **{
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'LOCATION': '127.0.0.1:11211', 'TIMEOUT': 30,
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})
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"""
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try:
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# Try to get the CACHES entry for the given backend name first
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try:
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conf = settings.CACHES[backend]
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except KeyError:
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try:
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# Trying to import the given backend, in case it's a dotted path
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import_by_path(backend)
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except ImproperlyConfigured as e:
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raise InvalidCacheBackendError("Could not find backend '%s': %s" % (
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backend, e))
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location = kwargs.pop('LOCATION', '')
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params = kwargs
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else:
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params = conf.copy()
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params.update(kwargs)
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backend = params.pop('BACKEND')
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location = params.pop('LOCATION', '')
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backend_cls = import_by_path(backend)
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except (AttributeError, ImportError, ImproperlyConfigured) as e:
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raise InvalidCacheBackendError(
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"Could not find backend '%s': %s" % (backend, e))
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cache = backend_cls(location, params)
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# Some caches -- python-memcached in particular -- need to do a cleanup at the
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# end of a request cycle. If not implemented in a particular backend
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# cache.close is a no-op
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signals.request_finished.connect(cache.close)
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return cache
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cache = get_cache(DEFAULT_CACHE_ALIAS)
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