wcs/wcs/cache.py

55 lines
2.1 KiB
Python

# w.c.s. - web application for online forms
# Copyright (C) 2005-2017 Entr'ouvert
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, see <http://www.gnu.org/licenses/>.
from django.core.cache.backends.base import InvalidCacheBackendError
from django.core.exceptions import ImproperlyConfigured
from django.utils.module_loading import import_string
from quixote import get_publisher
class TenantBaseCache:
'''Prepend the tenant application directory to the cache prefix'''
def set_key_prefix(self, prefix):
self.__key_prefix = prefix
def get_key_prefix(self):
if get_publisher():
return '%s_%s' % (get_publisher().app_dir, self.__key_prefix)
return self.__key_prefix
key_prefix = property(get_key_prefix, set_key_prefix)
__DERIVED_CLASSES = {}
def WcsTenantCache(host, params, **kwargs):
try:
backend = params['REAL_BACKEND']
except KeyError:
raise ImproperlyConfigured('The %s.WcsTenantCache backend needs a REAL_BACKEND parameter' % __name__)
try:
backend_cls = import_string(backend)
except ImportError as e:
raise InvalidCacheBackendError("Could not find backend '%s': %s" % (backend, e))
derived_cls_name = 'Tenant' + backend_cls.__name__
if derived_cls_name not in __DERIVED_CLASSES:
# dynamically create a new class with TenantBaseCache
# and the original class as parents
__DERIVED_CLASSES[derived_cls_name] = type(derived_cls_name, (TenantBaseCache, backend_cls), {})
return __DERIVED_CLASSES[derived_cls_name](host, params, **kwargs)