import sys
import six
from django.core.exceptions import ImproperlyConfigured
from .utils import import_attribute
class AppConfOptions(object):
def __init__(self, meta, prefix=None):
self.prefix = prefix
self.holder_path = getattr(meta, 'holder', 'django.conf.settings')
self.holder = import_attribute(self.holder_path)
self.proxy = getattr(meta, 'proxy', False)
self.required = getattr(meta, 'required', [])
self.configured_data = {}
def prefixed_name(self, name):
if name.startswith(self.prefix.upper()):
return name
return "%s_%s" % (self.prefix.upper(), name.upper())
def contribute_to_class(self, cls, name):
cls._meta = self
self.names = {}
self.defaults = {}
class AppConfMetaClass(type):
def __new__(cls, name, bases, attrs):
super_new = super(AppConfMetaClass, cls).__new__
parents = [b for b in bases if isinstance(b, AppConfMetaClass)]
if not parents:
return super_new(cls, name, bases, attrs)
# Create the class.
module = attrs.pop('__module__')
new_class = super_new(cls, name, bases, {'__module__': module})
attr_meta = attrs.pop('Meta', None)
if attr_meta:
meta = attr_meta
else:
attr_meta = type('Meta', (object,), {})
meta = getattr(new_class, 'Meta', None)
prefix = getattr(meta, 'prefix', getattr(meta, 'app_label', None))
if prefix is None:
# Figure out the prefix by looking one level up.
# For 'django.contrib.sites.models', this would be 'sites'.
model_module = sys.modules[new_class.__module__]
prefix = model_module.__name__.split('.')[-2]
new_class.add_to_class('_meta', AppConfOptions(meta, prefix))
new_class.add_to_class('Meta', attr_meta)
for parent in parents[::-1]:
if hasattr(parent, '_meta'):
new_class._meta.names.update(parent._meta.names)
new_class._meta.defaults.update(parent._meta.defaults)
new_class._meta.configured_data.update(
parent._meta.configured_data)
for name in filter(str.isupper, list(attrs.keys())):
prefixed_name = new_class._meta.prefixed_name(name)
new_class._meta.names[name] = prefixed_name
new_class._meta.defaults[prefixed_name] = attrs.pop(name)
# Add all attributes to the class.
for name, value in attrs.items():
new_class.add_to_class(name, value)
new_class._configure()
for name, value in six.iteritems(new_class._meta.configured_data):
prefixed_name = new_class._meta.prefixed_name(name)
setattr(new_class._meta.holder, prefixed_name, value)
new_class.add_to_class(name, value)
# Confirm presence of required settings.
for name in new_class._meta.required:
prefixed_name = new_class._meta.prefixed_name(name)
if not hasattr(new_class._meta.holder, prefixed_name):
raise ImproperlyConfigured('The required setting %s is'
' missing.' % prefixed_name)
return new_class
def add_to_class(cls, name, value):
if hasattr(value, 'contribute_to_class'):
value.contribute_to_class(cls, name)
else:
setattr(cls, name, value)
def _configure(cls):
# the ad-hoc settings class instance used to configure each value
obj = cls()
for name, prefixed_name in six.iteritems(obj._meta.names):
default_value = obj._meta.defaults.get(prefixed_name)
value = getattr(obj._meta.holder, prefixed_name, default_value)
callback = getattr(obj, "configure_%s" % name.lower(), None)
if callable(callback):
value = callback(value)
cls._meta.configured_data[name] = value
cls._meta.configured_data = obj.configure()
class AppConf(six.with_metaclass(AppConfMetaClass)):
"""
An app setting object to be used for handling app setting defaults
gracefully and providing a nice API for them.
"""
def __init__(self, **kwargs):
for name, value in six.iteritems(kwargs):
setattr(self, name, value)
def __dir__(self):
return sorted(list(set(self._meta.names.keys())))
# For instance access..
@property
def configured_data(self):
return self._meta.configured_data
# For Python < 2.6:
@property
def __members__(self):
return self.__dir__()
def __getattr__(self, name):
if self._meta.proxy:
return getattr(self._meta.holder, name)
raise AttributeError("%s not found. Use '%s' instead." %
(name, self._meta.holder_path))
def __setattr__(self, name, value):
if name == name.upper():
setattr(self._meta.holder,
self._meta.prefixed_name(name), value)
object.__setattr__(self, name, value)
def configure(self):
"""
Hook for doing any extra configuration, returning a dictionary
containing the configured data.
"""
return self.configured_data