*`queryset` - The queryset used for model instance lookups when validating the field input. Relationships must either set a queryset explicitly, or set`read_only=True`.

*`many` - If applied to a to-many relationship, you should set this argument to`True`.

*`allow_null` - If set to`True`, the field will accept values of`None` or the empty string for nullable relationships. Defaults to`False`.

*`pk_field` - Set to a field to control serialization/deserialization of the primary key's value. For example,`pk_field=UUIDField(format='hex')` would serialize a UUID primary key into its compact hex representation.

'incorrect_type':_('Incorrect type. Expected pk value, received {data_type}.'),

}

def__init__(self,**kwargs):

self.pk_field=kwargs.pop('pk_field',None)

super(PrimaryKeyRelatedField,self).__init__(**kwargs)

defuse_pk_only_optimization(self):

defto_internal_value(self,data):

ifself.pk_fieldisnotNone:

data=self.pk_field.to_internal_value(data)

try:

returnself.get_queryset().get(pk=data)

exceptObjectDoesNotExist:

self.fail('incorrect_type',data_type=type(data).__name__)

defto_representation(self,value):

ifself.pk_fieldisnotNone:

returnself.pk_field.to_representation(value)

returnvalue.pk

from .utilsimportmock_reverse,fail_reverse,BadType,MockObject,MockQueryset

fromdjango.core.exceptionsimportImproperlyConfigured

fromdjango.utils.datastructuresimportMultiValueDict

assertrepresentation==self.instance.pk

classTestProxiedPrimaryKeyRelatedField(APISimpleTestCase):

defsetUp(self):

self.queryset=MockQueryset([

MockObject(pk=uuid.UUID(int=0),name='foo'),

MockObject(pk=uuid.UUID(int=1),name='bar'),

MockObject(pk=uuid.UUID(int=2),name='baz')

])

self.instance=self.queryset.items[2]

self.field=serializers.PrimaryKeyRelatedField(

queryset=self.queryset,

pk_field=serializers.UUIDField(format='int')

)

deftest_pk_related_lookup_exists(self):

instance=self.field.to_internal_value(self.instance.pk.int)

assertinstanceisself.instance

deftest_pk_related_lookup_does_not_exist(self):

withpytest.raises(serializers.ValidationError)asexcinfo:

self.field.to_internal_value(4)

msg=excinfo.value.detail[0]

deftest_pk_related_lookup_invalid_type(self):

withpytest.raises(serializers.ValidationError)asexcinfo:

self.field.to_internal_value(BadType())

msg=excinfo.value.detail[0]

deftest_pk_representation(self):

representation=self.field.to_representation(self.instance)

assertrepresentation==self.instance.pk.int

classTestHyperlinkedIdentityField(APISimpleTestCase):

defsetUp(self):

self.instance=MockObject(pk=1,name='foo')