Django settings.py that can handle

multisettings.py

"""Multisite - individual site for request"""
from django.conf import settings
from threading import local


def make_tls_property(default=None):
    """Creates a class-wide instance property with a thread-specific value."""
    class TLSProperty(object):
        def __init__(self):
            self.local = local()

        def __get__(self, instance, cls):
            if not instance:
                return self
            return self.value

        def __set__(self, instance, value):
            # TODO: This is not called on any of the tests -- is this useless? 
            self.value = value

        def _get_value(self):
            return getattr(self.local, 'value', default)

        def _set_value(self, value):
            self.local.value = value

        value = property(_get_value, _set_value)

    return TLSProperty()


def _patch_setattr(obj):
    """Purpose of this is to allow changes to settings object again after it is
    changed to tls property.
    
    Without this patch the following is not possible::
    
        settings.SITE_ID = 1
        settings.SITE_ID = 42
        assert settings.SITE_ID == 42 # this fails without this patch
    
    """
    old_setattr = obj.__setattr__
    def wrap_setattr(self, name, value):
        try:
            getattr(self.__class__, name).value = value
        except AttributeError:
            old_setattr(name, value)
    obj.__class__.__setattr__ = wrap_setattr


_patch_setattr(settings)

DEFAULT_SITE_ID = getattr(settings, 'SITE_ID', None)
DEFAULT_MEDIA_URL = getattr(settings, 'MEDIA_URL', None)
DEFAULT_MEDIA_ROOT = getattr(settings, 'MEDIA_ROOT', None)
DEFAULT_MEDIA = getattr(settings, 'MEDIA', None)

settings.__class__.SITE_ID = make_tls_property(DEFAULT_SITE_ID)
settings.__class__.MEDIA_URL = make_tls_property(DEFAULT_MEDIA_URL)
settings.__class__.MEDIA_ROOT = make_tls_property(DEFAULT_MEDIA_ROOT)
settings.__class__.MEDIA = make_tls_property(DEFAULT_MEDIA)
settings.__class__.REQUEST = make_tls_property()