"""

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.

"""

from cgi import parse_qsl

from django.conf import settings

from django.core.cache.backends.base import InvalidCacheBackendError

BACKENDS = {

    # name for use in settings file --> name of module in "backends" directory

    'memcached': 'memcached',

    'locmem': 'locmem',

    'file': 'filebased',

    'db': 'db',

    'dummy': 'dummy',

}

DEPRECATED_BACKENDS = {

    # deprecated backend --> replacement module

    'simple': 'locmem',

}

def get_cache(backend_uri):

    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://"

    if scheme in DEPRECATED_BACKENDS:

        import warnings

        warnings.warn("'%s' backend is deprecated. Use '%s' instead." % 

            (scheme, DEPRECATED_BACKENDS[scheme]), DeprecationWarning)

        scheme = DEPRECATED_BACKENDS[scheme]

    if scheme not in BACKENDS:

        raise InvalidCacheBackendError, "%r is not a valid cache backend" % 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]

    cache_class = getattr(__import__('django.core.cache.backends.%s' % BACKENDS[scheme], {}, {}, ['']), 'CacheClass')

    return cache_class(host, params)

cache = get_cache(settings.CACHE_BACKEND)