我使用Django 2和Python 3.7。 我设置了这些模型。 其中一个(Coop)使用Many-To-Many方式依赖于另一个(CoopType)。
class CoopTypeManager(models.Manager):
def get_by_natural_key(self, name):
return self.get_or_create(name=name)[0]
class CoopType(models.Model):
name = models.CharField(max_length=200, null=False, unique=True)
objects = CoopTypeManager()
class CoopManager(models.Manager):
# Look up by coop type
def get_by_type(self, type):
qset = Coop.objects.filter(type__name=type,
enabled=True)
return qset
# Look up coops by a partial name (case insensitive)
def find_by_name(self, partial_name):
queryset = Coop.objects.filter(name__icontains=partial_name, enabled=True)
print(queryset.query)
return queryset
# Meant to look up coops case-insensitively by part of a type
def contains_type(self, types_arr):
filter = Q(
*[('type__name__icontains', type) for type in types_arr],
_connector=Q.OR
)
queryset = Coop.objects.filter(filter,
enabled=True)
return queryset
class Coop(models.Model):
objects = CoopManager()
name = models.CharField(max_length=250, null=False)
types = models.ManyToManyField(CoopType)
address = AddressField(on_delete=models.CASCADE)
enabled = models.BooleanField(default=True, null=False)
phone = PhoneNumberField(null=True)
email = models.EmailField(null=True)
web_site = models.TextField()
我设置了下面的序列化器,旨在以JSON形式返回数据......
class CoopTypeField(serializers.PrimaryKeyRelatedField):
queryset = CoopType.objects
def to_internal_value(self, data):
if type(data) == dict:
cooptype, created = CoopType.objects.get_or_create(**data)
# Replace the dict with the ID of the newly obtained object
data = cooptype.pk
return super().to_internal_value(data)
...
class CoopTypeSerializer(serializers.ModelSerializer):
class Meta:
model = CoopType
fields = ['id', 'name']
def create(self, validated_data):
"""
Create and return a new `CoopType` instance, given the validated data.
"""
return CoopType.objects.create(**validated_data)
def update(self, instance, validated_data):
"""
Update and return an existing `CoopType` instance, given the validated data.
"""
instance.name = validated_data.get('name', instance.name)
instance.save()
return instance
class CoopSerializer(serializers.ModelSerializer):
types = CoopTypeSerializer(many=True)
address = AddressTypeField()
class Meta:
model = Coop
fields = ['id', 'name', 'types', 'address', 'phone', 'enabled', 'email', 'web_site']
extra_kwargs = {
'phone': {
'required': False,
'allow_blank': True
}
}
def to_representation(self, instance):
rep = super().to_representation(instance)
rep['types'] = CoopTypeSerializer(instance.types).data
rep['address'] = AddressSerializer(instance.address).data
return rep
def create(self, validated_data):
#"""
#Create and return a new `Snippet` instance, given the validated data.
coop_types = validated_data.pop('types', {})
instance = super().create(validated_data)
for item in coop_types:
coop_type, _ = CoopType.objects.get_or_create(name=item['name']) #**item)
instance.types.add(coop_type)
return instance
然而,依赖的字段 "type "总是以 "null "的形式返回,尽管事实上我可以看到数据库中存在有效的数据。 以下是我运行curl请求时的情况
curl -v --header "Content-type: application/json" --request GET "http://127.0.0.1:8000/coops/?contains=resource"
[{"id":348,"name":"Garden Resources of Woodlawn (GRoW)","types":{"name":null}
我如何编辑我的序列化器,使其返回依赖类型的值?
尝试删除 rep['types'] = CoopTypeSerializer(instance.types).data
从 to_representation(...)
方法。
def to_representation(self, instance):
rep = super().to_representation(instance)
rep['types'] = CoopTypeSerializer(instance.types).data
rep['address'] = AddressSerializer(instance.address).data
return rep
或 使用 instance.types.all()
而不是 instance.types
因为,这里的 instance.types
是一个 经理人 方法,它不返回任何 QuerySet
def to_representation(self, instance):
rep = super().to_representation(instance)
rep['types'] = CoopTypeSerializer(instance.types.all(), many=True).data
rep['address'] = AddressSerializer(instance.address).data
return rep