django1/django/contrib/sites/managers.py

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from django.conf import settings
from django.db import models
from django.db.models.fields import FieldDoesNotExist
class CurrentSiteManager(models.Manager):
"Use this to limit objects to those associated with the current site."
def __init__(self, field_name=None):
super(CurrentSiteManager, self).__init__()
self.__field_name = field_name
self.__is_validated = False
def _validate_field_name(self):
field_names = self.model._meta.get_all_field_names()
# If a custom name is provided, make sure the field exists on the model
if self.__field_name is not None and self.__field_name not in field_names:
raise ValueError("%s couldn't find a field named %s in %s." % \
(self.__class__.__name__, self.__field_name, self.model._meta.object_name))
# Otherwise, see if there is a field called either 'site' or 'sites'
else:
for potential_name in ['site', 'sites']:
if potential_name in field_names:
self.__field_name = potential_name
self.__is_validated = True
break
# Now do a type check on the field (FK or M2M only)
try:
field = self.model._meta.get_field(self.__field_name)
if not isinstance(field, (models.ForeignKey, models.ManyToManyField)):
raise TypeError("%s must be a ForeignKey or ManyToManyField." %self.__field_name)
except FieldDoesNotExist:
raise ValueError("%s couldn't find a field named %s in %s." % \
(self.__class__.__name__, self.__field_name, self.model._meta.object_name))
self.__is_validated = True
def get_queryset(self):
if not self.__is_validated:
self._validate_field_name()
return super(CurrentSiteManager, self).get_queryset().filter(**{self.__field_name + '__id__exact': settings.SITE_ID})