将bool字段添加到Django查询集/序列化程序的最佳方式

Question

我有两种型号的

class A(models.Model):
name = models.CharField(max_length=32)
...
class B(models.Model):
fkey = models.ForeignKey("A", on_delete=models.CASCADE)
...

如果B中的一些对象引用了我的DRF序列化程序中的A，我想根据条件创建对象A的查询集

a1 = A.objects.create(name="1")
a2 = A.objects.create(name="2")
b1 = B.objects.create(fkey=a1)

a_objs = A.objects.filter()
serializer = ASerializer(a_objs, many=True)
serializer.data

{
{
"name": "1"
},
"b_attached": true
},
{
{
"name": "2"
},
"b_attached": false
}

实现这一目标的最佳方式是什么？

Answer 1

您的响应是无效的json！

您可以使用嵌套序列化来实现这样的功能：

from rest_framework import serializers
from .models import A, B

class ADetailSerializer(serializers.ModelSerializer):
class Meta:
model = A
fields = ("name",)

class ASerializer(serializers.ModelSerializer):
A_OBJ = serializers.SerializerMethodField(method_name='get_a_obj')
b_attached = serializers.SerializerMethodField(method_name='get_b_attached')
class Meta:
model = A
fields = ("A_OBJ", "b_attached")
def get_b_attached(self, obj):
if obj.b_set.exists():
return True
return False
def get_a_obj(self, obj):
return ADetailSerializer(obj, many=False).data

并且响应将是：

[
{
"A_OBJ": {
"name": "1"
},
"b_attached": true
},
{
"A_OBJ": {
"name": "2"
},
"b_attached": false
}
]