""" Caching framework. This package defines set of cache backends that all conform to a simple API. In a nutshell, a cache is a set of values -- which can be any object that may be pickled -- identified by string keys. For the complete API, see the abstract BaseCache class in django.core.cache.backends.base. Client code should not access a cache backend directly; instead it should either use the "cache" variable made available here, or it should use the get_cache() function made available here. get_cache() takes a backend URI (e.g. "memcached://127.0.0.1:11211/") and returns an instance of a backend cache class. See docs/cache.txt for information on the public API. """ try: # The mod_python version is more efficient, so try importing it first. from mod_python.util import parse_qsl except ImportError: try: # Python 2.6 and greater from urlparse import parse_qsl except ImportError: # Python 2.5, 2.4. Works on Python 2.6 but raises # PendingDeprecationWarning from cgi import parse_qsl from django.conf import settings from django.core import signals from django.core.cache.backends.base import InvalidCacheBackendError, CacheKeyWarning from django.utils import importlib # Name for use in settings file --> name of module in "backends" directory. # Any backend scheme that is not in this dictionary is treated as a Python # import path to a custom backend. BACKENDS = { 'memcached': 'memcached', 'locmem': 'locmem', 'file': 'filebased', 'db': 'db', 'dummy': 'dummy', } def parse_backend_uri(backend_uri): """ Converts the "backend_uri" into a cache scheme ('db', 'memcached', etc), a host and any extra params that are required for the backend. Returns a (scheme, host, params) tuple. """ if backend_uri.find(':') == -1: raise InvalidCacheBackendError("Backend URI must start with scheme://") scheme, rest = backend_uri.split(':', 1) if not rest.startswith('//'): raise InvalidCacheBackendError("Backend URI must start with scheme://") host = rest[2:] qpos = rest.find('?') if qpos != -1: params = dict(parse_qsl(rest[qpos+1:])) host = rest[2:qpos] else: params = {} if host.endswith('/'): host = host[:-1] return scheme, host, params def get_cache(backend_uri): scheme, host, params = parse_backend_uri(backend_uri) if scheme in BACKENDS: name = 'django.core.cache.backends.%s' % BACKENDS[scheme] else: name = scheme module = importlib.import_module(name) return module.CacheClass(host, params) cache = get_cache(settings.CACHE_BACKEND) # Some caches -- pythont-memcached in particular -- need to do a cleanup at the # end of a request cycle. If the cache provides a close() method, wire it up # here. if hasattr(cache, 'close'): signals.request_finished.connect(cache.close)