Added release notes for 0.9.1.
[philo.git] / philo / models / collections.py
1 from django.contrib.contenttypes import generic
2 from django.contrib.contenttypes.models import ContentType
3 from django.db import models
4
5 from philo.models.base import value_content_type_limiter, register_value_model
6 from philo.utils import fattr
7
8
9 __all__ = ('Collection', 'CollectionMember')
10
11
12 class Collection(models.Model):
13         """
14         Collections are curated ordered groupings of arbitrary models.
15         
16         """
17         #: :class:`CharField` with max_length 255
18         name = models.CharField(max_length=255)
19         #: Optional :class:`TextField`
20         description = models.TextField(blank=True, null=True)
21         
22         @fattr(short_description='Members')
23         def get_count(self):
24                 """Returns the number of items in the collection."""
25                 return self.members.count()
26         
27         def __unicode__(self):
28                 return self.name
29         
30         class Meta:
31                 app_label = 'philo'
32
33
34 class CollectionMemberManager(models.Manager):
35         use_for_related_fields = True
36
37         def with_model(self, model):
38                 """
39                 Given a model class or instance, returns a queryset of all instances of that model which have collection members in this manager's scope.
40                 
41                 Example::
42                 
43                         >>> from philo.models import Collection
44                         >>> from django.contrib.auth.models import User
45                         >>> collection = Collection.objects.get(name="Foo")
46                         >>> collection.members.all()
47                         [<CollectionMember: Foo - user1>, <CollectionMember: Foo - user2>, <CollectionMember: Foo - Spam & Eggs>]
48                         >>> collection.members.with_model(User)
49                         [<User: user1>, <User: user2>]
50                 
51                 """
52                 return model._default_manager.filter(pk__in=self.filter(member_content_type=ContentType.objects.get_for_model(model)).values_list('member_object_id', flat=True))
53
54
55 class CollectionMember(models.Model):
56         """
57         The collection member model represents a generic link from a :class:`Collection` to an arbitrary model instance with an attached order.
58         
59         """
60         #: A :class:`CollectionMemberManager` instance
61         objects = CollectionMemberManager()
62         #: :class:`ForeignKey` to a :class:`Collection` instance.
63         collection = models.ForeignKey(Collection, related_name='members')
64         #: The numerical index of the item within the collection (optional).
65         index = models.PositiveIntegerField(verbose_name='Index', help_text='This will determine the ordering of the item within the collection. (Optional)', null=True, blank=True)
66         member_content_type = models.ForeignKey(ContentType, limit_choices_to=value_content_type_limiter, verbose_name='Member type')
67         member_object_id = models.PositiveIntegerField(verbose_name='Member ID')
68         #: :class:`GenericForeignKey` to an arbitrary model instance.
69         member = generic.GenericForeignKey('member_content_type', 'member_object_id')
70         
71         def __unicode__(self):
72                 return u'%s - %s' % (self.collection, self.member)
73         
74         class Meta:
75                 app_label = 'philo'
76
77
78 register_value_model(Collection)