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from __future__ import unicode_literals
from functools import total_ordering
from operator import attrgetter
from django import VERSION
from django.conf import settings
from django.contrib.contenttypes.fields import GenericRelation
from django.contrib.contenttypes.models import ContentType
from django.db import models, router
from django.db.models import signals
from django.db.models.fields import Field
from django.db.models.fields.related import (ManyToManyRel, OneToOneRel,
RelatedField)
from django.db.models.query_utils import PathInfo
from django.utils import six
from django.utils.text import capfirst
from django.utils.translation import ugettext_lazy as _
from taggit.forms import TagField
from taggit.models import CommonGenericTaggedItemBase, TaggedItem
from taggit.utils import (_related_model, _remote_field,
require_instance_manager)
if VERSION >= (1, 9):
from django.db.models.fields.related import lazy_related_operation
else:
from django.db.models.fields.related import add_lazy_relation
class TaggableRel(ManyToManyRel):
def __init__(self, field, related_name, through, to=None):
# rel.to renamed to rel.model in Django 1.9
if VERSION >= (1, 9):
self.model = to
else:
self.to = to
self.related_name = related_name
self.limit_choices_to = {}
self.symmetrical = True
self.multiple = True
self.through = through
self.field = field
self.through_fields = None
def get_joining_columns(self):
return self.field.get_reverse_joining_columns()
def get_extra_restriction(self, where_class, alias, related_alias):
return self.field.get_extra_restriction(where_class, related_alias, alias)
class ExtraJoinRestriction(object):
"""
An extra restriction used for contenttype restriction in joins.
"""
contains_aggregate = False
def __init__(self, alias, col, content_types):
self.alias = alias
self.col = col
self.content_types = content_types
def as_sql(self, compiler, connection):
qn = compiler.quote_name_unless_alias
if len(self.content_types) == 1:
extra_where = "%s.%s = %%s" % (qn(self.alias), qn(self.col))
else:
extra_where = "%s.%s IN (%s)" % (qn(self.alias), qn(self.col),
','.join(['%s'] * len(self.content_types)))
return extra_where, self.content_types
def relabel_aliases(self, change_map):
self.alias = change_map.get(self.alias, self.alias)
def clone(self):
return self.__class__(self.alias, self.col, self.content_types[:])
class _TaggableManager(models.Manager):
def __init__(self, through, model, instance, prefetch_cache_name):
self.through = through
self.model = model
self.instance = instance
self.prefetch_cache_name = prefetch_cache_name
self._db = None
def is_cached(self, instance):
return self.prefetch_cache_name in instance._prefetched_objects_cache
def get_queryset(self, extra_filters=None):
try:
return self.instance._prefetched_objects_cache[self.prefetch_cache_name]
except (AttributeError, KeyError):
kwargs = extra_filters if extra_filters else {}
return self.through.tags_for(self.model, self.instance, **kwargs)
def get_prefetch_queryset(self, instances, queryset=None):
if queryset is not None:
raise ValueError("Custom queryset can't be used for this lookup.")
instance = instances[0]
from django.db import connections
db = self._db or router.db_for_read(instance.__class__, instance=instance)
fieldname = ('object_id' if issubclass(self.through, CommonGenericTaggedItemBase)
else 'content_object')
fk = self.through._meta.get_field(fieldname)
query = {
'%s__%s__in' % (self.through.tag_relname(), fk.name): {obj._get_pk_val() for obj in instances}
}
join_table = self.through._meta.db_table
source_col = fk.column
connection = connections[db]
qn = connection.ops.quote_name
qs = self.get_queryset(query).using(db).extra(
select={
'_prefetch_related_val': '%s.%s' % (qn(join_table), qn(source_col))
}
)
return (qs,
attrgetter('_prefetch_related_val'),
lambda obj: obj._get_pk_val(),
False,
self.prefetch_cache_name)
def _lookup_kwargs(self):
return self.through.lookup_kwargs(self.instance)
@require_instance_manager
def add(self, *tags):
db = router.db_for_write(self.through, instance=self.instance)
tag_objs = self._to_tag_model_instances(tags)
new_ids = {t.pk for t in tag_objs}
# NOTE: can we hardcode 'tag_id' here or should the column name be got
# dynamically from somewhere?
vals = (self.through._default_manager.using(db)
.values_list('tag_id', flat=True)
.filter(**self._lookup_kwargs()))
new_ids = new_ids - set(vals)
signals.m2m_changed.send(
sender=self.through, action="pre_add",
instance=self.instance, reverse=False,
model=self.through.tag_model(), pk_set=new_ids, using=db,
)
for tag in tag_objs:
self.through._default_manager.using(db).get_or_create(
tag=tag, **self._lookup_kwargs())
signals.m2m_changed.send(
sender=self.through, action="post_add",
instance=self.instance, reverse=False,
model=self.through.tag_model(), pk_set=new_ids, using=db,
)
def _to_tag_model_instances(self, tags):
"""
Takes an iterable containing either strings, tag objects, or a mixture
of both and returns set of tag objects.
"""
db = router.db_for_write(self.through, instance=self.instance)
str_tags = set()
tag_objs = set()
for t in tags:
if isinstance(t, self.through.tag_model()):
tag_objs.add(t)
elif isinstance(t, six.string_types):
str_tags.add(t)
else:
raise ValueError(
"Cannot add {0} ({1}). Expected {2} or str.".format(
t, type(t), type(self.through.tag_model())))
case_insensitive = getattr(settings, 'TAGGIT_CASE_INSENSITIVE', False)
manager = self.through.tag_model()._default_manager.using(db)
if case_insensitive:
# Some databases can do case-insensitive comparison with IN, which
# would be faster, but we can't rely on it or easily detect it.
existing = []
tags_to_create = []
for name in str_tags:
try:
tag = manager.get(name__iexact=name)
existing.append(tag)
except self.through.tag_model().DoesNotExist:
tags_to_create.append(name)
else:
# If str_tags has 0 elements Django actually optimizes that to not
# do a query. Malcolm is very smart.
existing = manager.filter(name__in=str_tags)
tags_to_create = str_tags - {t.name for t in existing}
tag_objs.update(existing)
for new_tag in tags_to_create:
if case_insensitive:
try:
tag = manager.get(name__iexact=new_tag)
except self.through.tag_model().DoesNotExist:
tag = manager.create(name=new_tag)
else:
tag = manager.create(name=new_tag)
tag_objs.add(tag)
return tag_objs
@require_instance_manager
def names(self):
return self.get_queryset().values_list('name', flat=True)
@require_instance_manager
def slugs(self):
return self.get_queryset().values_list('slug', flat=True)
@require_instance_manager
def set(self, *tags, **kwargs):
"""
Set the object's tags to the given n tags. If the clear kwarg is True
then all existing tags are removed (using `.clear()`) and the new tags
added. Otherwise, only those tags that are not present in the args are
removed and any new tags added.
"""
db = router.db_for_write(self.through, instance=self.instance)
clear = kwargs.pop('clear', False)
if clear:
self.clear()
self.add(*tags)
else:
# make sure we're working with a collection of a uniform type
objs = self._to_tag_model_instances(tags)
# get the existing tag strings
old_tag_strs = set(self.through._default_manager
.using(db)
.filter(**self._lookup_kwargs())
.values_list('tag__name', flat=True))
new_objs = []
for obj in objs:
if obj.name in old_tag_strs:
old_tag_strs.remove(obj.name)
else:
new_objs.append(obj)
self.remove(*old_tag_strs)
self.add(*new_objs)
@require_instance_manager
def remove(self, *tags):
if not tags:
return
db = router.db_for_write(self.through, instance=self.instance)
qs = (self.through._default_manager.using(db)
.filter(**self._lookup_kwargs())
.filter(tag__name__in=tags))
old_ids = set(qs.values_list('tag_id', flat=True))
signals.m2m_changed.send(
sender=self.through, action="pre_remove",
instance=self.instance, reverse=False,
model=self.through.tag_model(), pk_set=old_ids, using=db,
)
qs.delete()
signals.m2m_changed.send(
sender=self.through, action="post_remove",
instance=self.instance, reverse=False,
model=self.through.tag_model(), pk_set=old_ids, using=db,
)
@require_instance_manager
def clear(self):
db = router.db_for_write(self.through, instance=self.instance)
signals.m2m_changed.send(
sender=self.through, action="pre_clear",
instance=self.instance, reverse=False,
model=self.through.tag_model(), pk_set=None, using=db,
)
self.through._default_manager.using(db).filter(
**self._lookup_kwargs()).delete()
signals.m2m_changed.send(
sender=self.through, action="post_clear",
instance=self.instance, reverse=False,
model=self.through.tag_model(), pk_set=None, using=db,
)
def most_common(self, min_count=None, extra_filters=None):
queryset = self.get_queryset(extra_filters).annotate(
num_times=models.Count(self.through.tag_relname())
).order_by('-num_times')
if min_count:
queryset = queryset.filter(num_times__gte=min_count)
return queryset
@require_instance_manager
def similar_objects(self):
lookup_kwargs = self._lookup_kwargs()
lookup_keys = sorted(lookup_kwargs)
qs = self.through.objects.values(*six.iterkeys(lookup_kwargs))
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(lookup_keys[0])
remote_field = _remote_field(f)
rel_model = _related_model(_remote_field(f))
objs = rel_model._default_manager.filter(**{
"%s__in" % remote_field.field_name: [r["content_object"] for r in qs]
})
for obj in objs:
items[(getattr(obj, remote_field.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.items():
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
# _TaggableManager needs to be hashable but BaseManagers in Django 1.8+ overrides
# the __eq__ method which makes the default __hash__ method disappear.
# This checks if the __hash__ attribute is None, and if so, it reinstates the original method.
if models.Manager.__hash__ is None:
__hash__ = object.__hash__
@total_ordering
class TaggableManager(RelatedField, Field):
# Field flags
many_to_many = True
many_to_one = False
one_to_many = False
one_to_one = False
_related_name_counter = 0
def __init__(self, verbose_name=_("Tags"),
help_text=_("A comma-separated list of tags."),
through=None, blank=False, related_name=None, to=None,
manager=_TaggableManager):
self.through = through or TaggedItem
self.swappable = False
self.manager = manager
rel = TaggableRel(self, related_name, self.through, to=to)
Field.__init__(
self,
verbose_name=verbose_name,
help_text=help_text,
blank=blank,
null=True,
serialize=False,
rel=rel,
)
# NOTE: `to` is ignored, only used via `deconstruct`.
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 = self.manager(
through=self.through,
model=model,
instance=instance,
prefetch_cache_name=self.name
)
return manager
def deconstruct(self):
"""
Deconstruct the object, used with migrations.
"""
name, path, args, kwargs = super(TaggableManager, self).deconstruct()
# Remove forced kwargs.
for kwarg in ('serialize', 'null'):
del kwargs[kwarg]
# Add arguments related to relations.
# Ref: https://github.com/alex/django-taggit/issues/206#issuecomment-37578676
rel = _remote_field(self)
if isinstance(rel.through, six.string_types):
kwargs['through'] = rel.through
elif not rel.through._meta.auto_created:
kwargs['through'] = "%s.%s" % (rel.through._meta.app_label, rel.through._meta.object_name)
related_model = _related_model(rel)
if isinstance(related_model, six.string_types):
kwargs['to'] = related_model
else:
kwargs['to'] = '%s.%s' % (related_model._meta.app_label, related_model._meta.object_name)
return name, path, args, kwargs
def contribute_to_class(self, cls, name):
self.set_attributes_from_name(name)
self.model = cls
self.opts = cls._meta
cls._meta.add_field(self)
setattr(cls, name, self)
if not cls._meta.abstract:
# rel.to renamed to remote_field.model in Django 1.9
if VERSION >= (1, 9):
if isinstance(self.remote_field.model, six.string_types):
def resolve_related_class(cls, model, field):
field.remote_field.model = model
lazy_related_operation(
resolve_related_class, cls, self.remote_field.model, field=self
)
else:
if isinstance(self.rel.to, six.string_types):
def resolve_related_class(field, model, cls):
field.rel.to = model
add_lazy_relation(cls, self, self.rel.to, resolve_related_class)
if isinstance(self.through, six.string_types):
if VERSION >= (1, 9):
def resolve_related_class(cls, model, field):
self.through = model
self.remote_field.through = model
self.post_through_setup(cls)
lazy_related_operation(
resolve_related_class, cls, self.through, field=self
)
else:
def resolve_related_class(field, model, cls):
self.through = model
_remote_field(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 get_internal_type(self):
return 'ManyToManyField'
def __lt__(self, other):
"""
Required contribute_to_class as Django uses bisect
for ordered class contribution and bisect requires
a orderable type in py3.
"""
return False
def post_through_setup(self, cls):
self.use_gfk = (
self.through is None or issubclass(self.through, CommonGenericTaggedItemBase)
)
# rel.to renamed to remote_field.model in Django 1.9
if VERSION >= (1, 9):
if not self.remote_field.model:
self.remote_field.model = self.through._meta.get_field("tag").remote_field.model
else:
if not self.rel.to:
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')
for rel in cls._meta.local_many_to_many:
if rel == self or not isinstance(rel, TaggableManager):
continue
if rel.through == self.through:
raise ValueError('You can\'t have two TaggableManagers with the'
' same through model.')
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.model_name
def m2m_reverse_name(self):
return self.through._meta.get_field('tag').column
def m2m_reverse_field_name(self):
return self.through._meta.get_field('tag').name
def m2m_target_field_name(self):
return self.model._meta.pk.name
def m2m_reverse_target_field_name(self):
# rel.to renamed to remote_field.model in Django 1.9
if VERSION >= (1, 9):
return self.remote_field.model._meta.pk.name
else:
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 bulk_related_objects(self, new_objs, using):
return []
def extra_filters(self, pieces, pos, negate):
if negate or not self.use_gfk:
return []
prefix = "__".join(["tagged_items"] + pieces[:pos - 2])
get = ContentType.objects.get_for_model
cts = [get(obj) for obj in _get_subclasses(self.model)]
if len(cts) == 1:
return [("%s__content_type" % prefix, cts[0])]
return [("%s__content_type__in" % prefix, cts)]
def get_extra_join_sql(self, connection, qn, lhs_alias, rhs_alias):
model_name = self.through._meta.model_name
if rhs_alias == '%s_%s' % (self.through._meta.app_label, model_name):
alias_to_join = rhs_alias
else:
alias_to_join = lhs_alias
extra_col = self.through._meta.get_field('content_type').column
content_type_ids = [ContentType.objects.get_for_model(subclass).pk for
subclass in _get_subclasses(self.model)]
if len(content_type_ids) == 1:
content_type_id = content_type_ids[0]
extra_where = " AND %s.%s = %%s" % (qn(alias_to_join),
qn(extra_col))
params = [content_type_id]
else:
extra_where = " AND %s.%s IN (%s)" % (qn(alias_to_join),
qn(extra_col),
','.join(['%s'] *
len(content_type_ids)))
params = content_type_ids
return extra_where, params
def _get_mm_case_path_info(self, direct=False):
pathinfos = []
linkfield1 = self.through._meta.get_field('content_object')
linkfield2 = self.through._meta.get_field(self.m2m_reverse_field_name())
if direct:
join1infos = linkfield1.get_reverse_path_info()
join2infos = linkfield2.get_path_info()
else:
join1infos = linkfield2.get_reverse_path_info()
join2infos = linkfield1.get_path_info()
pathinfos.extend(join1infos)
pathinfos.extend(join2infos)
return pathinfos
def _get_gfk_case_path_info(self, direct=False):
pathinfos = []
from_field = self.model._meta.pk
opts = self.through._meta
linkfield = self.through._meta.get_field(self.m2m_reverse_field_name())
if direct:
join1infos = [PathInfo(self.model._meta, opts, [from_field], _remote_field(self), True, False)]
join2infos = linkfield.get_path_info()
else:
join1infos = linkfield.get_reverse_path_info()
join2infos = [PathInfo(opts, self.model._meta, [from_field], self, True, False)]
pathinfos.extend(join1infos)
pathinfos.extend(join2infos)
return pathinfos
def get_path_info(self):
if self.use_gfk:
return self._get_gfk_case_path_info(direct=True)
else:
return self._get_mm_case_path_info(direct=True)
def get_reverse_path_info(self):
if self.use_gfk:
return self._get_gfk_case_path_info(direct=False)
else:
return self._get_mm_case_path_info(direct=False)
def get_joining_columns(self, reverse_join=False):
if reverse_join:
return ((self.model._meta.pk.column, "object_id"),)
else:
return (("object_id", self.model._meta.pk.column),)
def get_extra_restriction(self, where_class, alias, related_alias):
extra_col = self.through._meta.get_field('content_type').column
content_type_ids = [ContentType.objects.get_for_model(subclass).pk
for subclass in _get_subclasses(self.model)]
return ExtraJoinRestriction(related_alias, extra_col, content_type_ids)
def get_reverse_joining_columns(self):
return self.get_joining_columns(reverse_join=True)
@property
def related_fields(self):
return [(self.through._meta.get_field('object_id'), self.model._meta.pk)]
@property
def foreign_related_fields(self):
return [self.related_fields[0][1]]
def _get_subclasses(model):
subclasses = [model]
for field in model._meta.get_fields():
if isinstance(field, OneToOneRel) and getattr(_remote_field(field.field), "parent_link", None):
subclasses.extend(_get_subclasses(field.related_model))
return subclasses