Django Rest 框架嵌套关系

Question

在我的模型中

models.py

class Province(models.Model):
name = models.CharField(max_length=128, verbose_name=u"province")
class City(models.Model):
province = models.ForeignKey("system.Province", related_name='cities', verbose_name=u"province")
name = models.CharField(max_length=128, verbose_name=u"name")
class District(models.Model):
city = models.ForeignKey("system.City", related_name='districts', verbose_name=u"city")
name = models.CharField(max_length=128, verbose_name=u"name")

---

serializers.py

class DistrictSerializer(serializers.ModelSerializer):
class Meta:
model = District
fields = ('id', 'name')

class CitySerializer(serializers.ModelSerializer):
districts = DistrictSerializer(many=True, read_only=True)
class Meta:
model = City
fields = ('id', 'name', 'districts')

class ProvinceSerializer(serializers.ModelSerializer):
cities = CitySerializer(many=True, read_only=True)
class Meta:
model = Province
fields = ('id', 'name', 'cities')

---

当我向网址/系统/省份/1/发出GET请求时，我得到的是像json这样的字符串

{
"id": 1,
"name": "广东省",
"cities": [
{
"id": 1,
"name": "广州市",
"districts": [
{
"id": 1,
"name": "天河区"
},
{
"id": 2,
"name": "海珠区"
}
]
},
{
"id": 2,
"name": "汕头市",
"districts": [
{
"id": 3,
"name": "朝阳区"
}
]
},
{
"id": 3,
"name": "湛江市",
"districts": []
},
{
"id": 4,
"name": "韶关市",
"districts": []
}
]

}

小区JSON不是我想要的。 如何防止自动加载区域

Answer 1

(推荐(从元类下方删除字段"区"。

class Meta:
model = City
fields = ('id', 'name')

或者，如果您必须更新与此字段相关的任何值，请使用extra_kwargs变量使此字段write_only。

class Meta:
model = City
extra_kwargs = {'districts': {'write_only': True}}
fields = ('id', 'name', 'districts')

Answer 2

class DistrictSerializer(serializers.ModelSerializer):
class Meta:
model = District
fields = ('id', 'name')
class CitySerializer(serializers.ModelSerializer): 
districts = DistrictSerializer(many=True, read_only=True)
class Meta:
model = City
fields = ('id', 'name', 'districts')
class CityForProvinceSerializer(serializers.ModelSerializer): 
class Meta:
model = City
fields = ('id', 'name')
class ProvinceSerializer(serializers.ModelSerializer):
cities = CityForProvinceSerializer(many=True, read_only=True)
class Meta:
model = Province
fields = ('id', 'name', 'cities')

或

---

class DynamicFieldsModelSerializer(ModelSerializer):
"""
A ModelSerializer that takes an additional `fields` argument that
controls which fields should be displayed.
"""
def __init__(self, *args, **kwargs):
# Don't pass the 'fields' arg up to the superclass
fields = kwargs.pop('fields', None)
exclude = kwargs.pop('exclude', None)
# Instantiate the superclass normally
super(DynamicFieldsModelSerializer, self).__init__(*args, **kwargs)
if fields is not None:
# Drop any fields that are not specified in the `fields` argument.
allowed = set(fields)
existing = set(self.fields.keys())
for field_name in existing - allowed:
self.fields.pop(field_name)
if exclude is not None:
not_allowed = set(exclude)
for exclude_name in not_allowed:
self.fields.pop(exclude_name)

class DistrictSerializer(serializers.ModelSerializer):
class Meta:
model = District
fields = ('id', 'name')
class CitySerializer(DynamicFieldsModelSerializer): 
districts = DistrictSerializer(many=True, read_only=True)
class Meta:
model = City
fields = ('id', 'name', 'districts')
class ProvinceSerializer(serializers.ModelSerializer):
cities = serializers.SerializerMethodField()
class Meta:
model = Province
fields = ('id', 'name', 'cities')
def get_cities(self, instance):
return CitySerializer(instance.cities.all(), many=True, fields=('id', 'name')).data