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from django.contrib.contenttypes.generic import GenericRelation
from django.contrib.contenttypes.models import ContentType
from django.db import models
from django.db.models.fields.related import ManyToManyRel, RelatedField, add_lazy_relation
from django.db.models.related import RelatedObject
from django.utils.text import capfirst
from django.utils.translation import ugettext_lazy as _
from taggit.forms import TagField
from taggit.models import TaggedItem, GenericTaggedItemBase
from taggit.utils import require_instance_manager
try:
all
except NameError:
# 2.4 compat
try:
from django.utils.itercompat import all
except ImportError:
# 1.1.X compat
def all(iterable):
for item in iterable:
if not item:
return False
return True
class TaggableRel(ManyToManyRel):
def __init__(self):
self.related_name = None
self.limit_choices_to = {}
self.symmetrical = True
self.multiple = True
self.through = None
class TaggableManager(RelatedField):
def __init__(self, verbose_name=_("Tags"),
help_text=_("A comma-separated list of tags."), through=None, blank=False):
self.through = through or TaggedItem
self.rel = TaggableRel()
self.verbose_name = verbose_name
self.help_text = help_text
self.blank = blank
self.editable = True
self.unique = False
self.creates_table = False
self.db_column = None
self.choices = None
self.serialize = False
self.null = True
self.creation_counter = models.Field.creation_counter
models.Field.creation_counter += 1
def __get__(self, instance, model):
if instance is not None and instance.pk is None:
raise ValueError("%s objects need to have a primary key value "
"before you can access their tags." % model.__name__)
manager = _TaggableManager(
through=self.through, model=model, instance=instance
)
return manager
def contribute_to_class(self, cls, name):
self.name = self.column = name
self.model = cls
cls._meta.add_field(self)
setattr(cls, name, self)
if not cls._meta.abstract:
if isinstance(self.through, basestring):
def resolve_related_class(field, model, cls):
self.through = model
self.post_through_setup(cls)
add_lazy_relation(
cls, self, self.through, resolve_related_class
)
else:
self.post_through_setup(cls)
def post_through_setup(self, cls):
self.use_gfk = (
self.through is None or issubclass(self.through, GenericTaggedItemBase)
)
self.rel.to = self.through._meta.get_field("tag").rel.to
if self.use_gfk:
tagged_items = GenericRelation(self.through)
tagged_items.contribute_to_class(cls, "tagged_items")
def save_form_data(self, instance, value):
getattr(instance, self.name).set(*value)
def formfield(self, form_class=TagField, **kwargs):
defaults = {
"label": capfirst(self.verbose_name),
"help_text": self.help_text,
"required": not self.blank
}
defaults.update(kwargs)
return form_class(**defaults)
def value_from_object(self, instance):
if instance.pk:
return self.through.objects.filter(**self.through.lookup_kwargs(instance))
return self.through.objects.none()
def related_query_name(self):
return self.model._meta.module_name
def m2m_reverse_name(self):
return self.through._meta.get_field_by_name("tag")[0].column
def m2m_target_field_name(self):
return self.model._meta.pk.name
def m2m_reverse_target_field_name(self):
return self.rel.to._meta.pk.name
def m2m_column_name(self):
if self.use_gfk:
return self.through._meta.virtual_fields[0].fk_field
return self.through._meta.get_field('content_object').column
def db_type(self, connection=None):
return None
def m2m_db_table(self):
return self.through._meta.db_table
def extra_filters(self, pieces, pos, negate):
if negate or not self.use_gfk:
return []
prefix = "__".join(["tagged_items"] + pieces[:pos-2])
cts = map(ContentType.objects.get_for_model, _get_subclasses(self.model))
if len(cts) == 1:
return [("%s__content_type" % prefix, cts[0])]
return [("%s__content_type__in" % prefix, cts)]
def bulk_related_objects(self, new_objs, using):
return []
class _TaggableManager(models.Manager):
def __init__(self, through, model, instance):
self.through = through
self.model = model
self.instance = instance
def get_query_set(self):
return self.through.tags_for(self.model, self.instance)
def _lookup_kwargs(self):
return self.through.lookup_kwargs(self.instance)
@require_instance_manager
def add(self, *tags):
str_tags = set([
t
for t in tags
if not isinstance(t, self.through.tag_model())
])
tag_objs = set(tags) - str_tags
# If str_tags has 0 elements Django actually optimizes that to not do a
# query. Malcolm is very smart.
existing = self.through.tag_model().objects.filter(
name__in=str_tags
)
tag_objs.update(existing)
for new_tag in str_tags - set(t.name for t in existing):
tag_objs.add(self.through.tag_model().objects.create(name=new_tag))
for tag in tag_objs:
self.through.objects.get_or_create(tag=tag, **self._lookup_kwargs())
@require_instance_manager
def set(self, *tags):
self.clear()
self.add(*tags)
@require_instance_manager
def remove(self, *tags):
self.through.objects.filter(**self._lookup_kwargs()).filter(
tag__name__in=tags).delete()
@require_instance_manager
def clear(self):
self.through.objects.filter(**self._lookup_kwargs()).delete()
def most_common(self):
return self.get_query_set().annotate(
num_times=models.Count(self.through.tag_relname())
).order_by('-num_times')
@require_instance_manager
def similar_objects(self):
lookup_kwargs = self._lookup_kwargs()
lookup_keys = sorted(lookup_kwargs)
qs = self.through.objects.values(*lookup_kwargs.keys())
qs = qs.annotate(n=models.Count('pk'))
qs = qs.exclude(**lookup_kwargs)
qs = qs.filter(tag__in=self.all())
qs = qs.order_by('-n')
# TODO: This all feels like a bit of a hack.
items = {}
if len(lookup_keys) == 1:
# Can we do this without a second query by using a select_related()
# somehow?
f = self.through._meta.get_field_by_name(lookup_keys[0])[0]
objs = f.rel.to._default_manager.filter(**{
"%s__in" % f.rel.field_name: [r["content_object"] for r in qs]
})
for obj in objs:
items[(getattr(obj, f.rel.field_name),)] = obj
else:
preload = {}
for result in qs:
preload.setdefault(result['content_type'], set())
preload[result["content_type"]].add(result["object_id"])
for ct, obj_ids in preload.iteritems():
ct = ContentType.objects.get_for_id(ct)
for obj in ct.model_class()._default_manager.filter(pk__in=obj_ids):
items[(ct.pk, obj.pk)] = obj
results = []
for result in qs:
obj = items[
tuple(result[k] for k in lookup_keys)
]
obj.similar_tags = result["n"]
results.append(obj)
return results
def _get_subclasses(model):
subclasses = [model]
for f in model._meta.get_all_field_names():
field = model._meta.get_field_by_name(f)[0]
if (isinstance(field, RelatedObject) and
getattr(field.field.rel, "parent_link", None)):
subclasses.extend(_get_subclasses(field.model))
return subclasses
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