# Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
#
from django.conf import settings
+from django.contrib.contenttypes.fields import GenericForeignKey
+from django.contrib.contenttypes.models import ContentType
from django.core.cache import caches
from django.contrib.auth.models import User
+from django.core.exceptions import ObjectDoesNotExist
from django.db import models
from django.db.models import permalink
+from django.db.models.query import Prefetch
from django.dispatch import Signal
from django.utils.translation import ugettext_lazy as _
)
+class TagRelation(models.Model):
+
+ tag = models.ForeignKey('Tag', verbose_name=_('tag'), related_name='items')
+ content_type = models.ForeignKey(ContentType, verbose_name=_('content type'))
+ object_id = models.PositiveIntegerField(_('object id'), db_index=True)
+ content_object = GenericForeignKey('content_type', 'object_id')
+
+ class Meta:
+ db_table = 'catalogue_tag_relation'
+ unique_together = (('tag', 'content_type', 'object_id'),)
+
+ def __unicode__(self):
+ try:
+ return u'%s [%s]' % (self.content_type.get_object_for_this_type(pk=self.object_id), self.tag)
+ except ObjectDoesNotExist:
+ return u'<deleted> [%s]' % self.tag
+
+
class Tag(TagBase):
"""A tag attachable to books and fragments (and possibly anything).
after_change = Signal(providing_args=['instance', 'languages'])
+ intermediary_table_model = TagRelation
+
class UrlDeprecationWarning(DeprecationWarning):
def __init__(self, tags=None):
super(Tag.UrlDeprecationWarning, self).__init__()
return meta_tags
-# Pickle complains about not having this.
-TagRelation = Tag.intermediary_table_model
+def prefetch_relations(objects, category, only_name=True):
+ queryset = TagRelation.objects.filter(tag__category=category).select_related('tag')
+ if only_name:
+ queryset = queryset.only('tag__name_pl', 'object_id')
+ return objects.prefetch_related(
+ Prefetch('tag_relations', queryset=queryset, to_attr='%s_relations' % category))
+
+
+def prefetched_relations(obj, category):
+ if hasattr(obj, '%s_relations' % category):
+ return getattr(obj, '%s_relations' % category)
+ else:
+ return None