TypeError: Object of type ManyRelatedManager is not JSON serializable in django rest framework
TypeError: Object of type ManyRelatedManager is not JSON serializable in django rest framework
我正在尝试将一些学生添加到老师class,使用他们的 ID 作为主键,但我遇到了上述错误。
我有这样的师生模型
class Student(TimeStampAbstractModel):
user = models.OneToOneField(User, related_name="student", on_delete=models.CASCADE)
college_name = models.CharField(max_length=255, default="", blank=True)
address = models.CharField(max_length=255, default="", blank=True)
def __str__(self):
return self.user.name
class Teacher(TimeStampAbstractModel):
user = models.OneToOneField(User, related_name="teacher", on_delete=models.CASCADE)
address = models.CharField(max_length=255, default="", blank=True)
students_in_class = models.ManyToManyField(Student,related_name="teacher")
def __str__(self):
return self.user.name
在这里,一个教师模型可以有很多学生 class 以及他们的 ID。我使用了一个 put api 调用来一键将学生添加到老师。
我的看法:
from rest_framework import status
class AddtoClassView(APIView):
def put(self,request,pk,*args,**kwargs):
id =pk
teacher = Teacher.objects.get(id=id)
serializer = TeacherSerializer(teacher,data=request.data)
if serializer.is_valid():
serializer.save()
print("iam if")
return Response({
"message":"Student has been added to class.",
"data": serializer.data
},status=status.HTTP_200_OK)
# else:
print("iam else")
return Response(serializer.data)
我的序列化器:
class TeacherSerializer(serializers.ModelSerializer):
students_in_class = serializers.PrimaryKeyRelatedField(
read_only= True
)
address = serializers.CharField(required=False)
# user = serializers.PrimaryKeyRelatedField(read_only=True)
class Meta:
model = Teacher
fields = ["address","students_in_class"]
# fields = '__all__'
def update(self, instance, validated_data):
instance.address = validated_data.get("address")
instance.save()
stu = validated_data.get("students_in_class")
print(stu)
if stu is not None:
print("iam stu")
instance.students_in_class.add(stu)
instance.save()
super(TeacherSerializer,self).update(instance, validated_data)
return instance
这里我用了students_in_class作为pk域(我还是没搞明白什么时候用integarfield,什么时候用pk域)。我知道,因为我将 ID 添加到 student_in_class 字段,所以我不应该将它用作 read_only = true
,但是我必须使用它,否则它会产生错误。如何解决这个问题?另外,我真的不知道在序列化器中定义哪些字段 class.
更新代码:
class TeacherSerializer(serializers.ModelSerializer):
# students_in_class = serializers.PrimaryKeyRelatedField(
# many = True, read_only= True
# )
students_in_class = serializers.ListField(
source="students_in_class.all",
child=serializers.PrimaryKeyRelatedField(queryset=Student.objects.all()),
)
address = serializers.CharField(required=False)
# user = serializers.PrimaryKeyRelatedField(read_only=True)
class Meta:
model = Teacher
fields = ["address","students_in_class"]
# fields = '__all__'
def update(self, instance, validated_data):
instance.address = validated_data['students_in_class']['all']
instance.save()
stu = validated_data.get("students_in_class")
print(stu)
if stu is not None:
print("iam stu")
instance.students_in_class.add(stu)
instance.save()
super(TeacherSerializer,self).update(instance, validated_data)
return instance
由于您使用的是 m2m 字段,因此您需要 students_in_class
的 ID 列表。所以解决方案将是这样的。 (免责声明:代码未经测试)。
class TeacherSerializer(serializers.ModelSerializer):
students_in_class = serializers.ListField(
source="students_in_class.all",
child=serializers.PrimaryKeyRelatedField(queryset=Student.objects.all()),
)
序列化错误将得到解决,因为现在您已将 students_in_class.all
作为来源。您需要像这样访问数据:validated_data['students_in_class']['all']
如果您想以不同的方式序列化您的输出,您可以将 students_in_class
设置为 write_only
并根据需要覆盖序列化程序表示。:
class TeacherSerializer(serializers.ModelSerializer):
students_in_class = serializers.ListField(
child=serializers.PrimaryKeyRelatedField(queryset=Student.objects.all()),
write_only=True
)
# your code
def to_representation(self, instance):
ret = super().to_representation(instance)
ret['students_in_class'] = StudentSerializer(instance.students_in_class.all(), many=True).data
return ret
以下代码有效:
class TeacherSerializer(serializers.ModelSerializer):
students_in_class = serializers.PrimaryKeyRelatedField(
many = True,queryset=Student.objects.all()
)
address = serializers.CharField(required=False)
class Meta:
model = Teacher
fields = ["address","students_in_class"]
def update(self, instance, validated_data):
instance.address = validated_data.get("address")
instance.save()
stu = validated_data.pop("students_in_class")
for stus in stu:
instance.students_in_class.add(stus)
instance.save()
super(TeacherSerializer,self).update(instance, validated_data)
return instance
我正在尝试将一些学生添加到老师class,使用他们的 ID 作为主键,但我遇到了上述错误。
我有这样的师生模型
class Student(TimeStampAbstractModel):
user = models.OneToOneField(User, related_name="student", on_delete=models.CASCADE)
college_name = models.CharField(max_length=255, default="", blank=True)
address = models.CharField(max_length=255, default="", blank=True)
def __str__(self):
return self.user.name
class Teacher(TimeStampAbstractModel):
user = models.OneToOneField(User, related_name="teacher", on_delete=models.CASCADE)
address = models.CharField(max_length=255, default="", blank=True)
students_in_class = models.ManyToManyField(Student,related_name="teacher")
def __str__(self):
return self.user.name
在这里,一个教师模型可以有很多学生 class 以及他们的 ID。我使用了一个 put api 调用来一键将学生添加到老师。
我的看法:
from rest_framework import status
class AddtoClassView(APIView):
def put(self,request,pk,*args,**kwargs):
id =pk
teacher = Teacher.objects.get(id=id)
serializer = TeacherSerializer(teacher,data=request.data)
if serializer.is_valid():
serializer.save()
print("iam if")
return Response({
"message":"Student has been added to class.",
"data": serializer.data
},status=status.HTTP_200_OK)
# else:
print("iam else")
return Response(serializer.data)
我的序列化器:
class TeacherSerializer(serializers.ModelSerializer):
students_in_class = serializers.PrimaryKeyRelatedField(
read_only= True
)
address = serializers.CharField(required=False)
# user = serializers.PrimaryKeyRelatedField(read_only=True)
class Meta:
model = Teacher
fields = ["address","students_in_class"]
# fields = '__all__'
def update(self, instance, validated_data):
instance.address = validated_data.get("address")
instance.save()
stu = validated_data.get("students_in_class")
print(stu)
if stu is not None:
print("iam stu")
instance.students_in_class.add(stu)
instance.save()
super(TeacherSerializer,self).update(instance, validated_data)
return instance
这里我用了students_in_class作为pk域(我还是没搞明白什么时候用integarfield,什么时候用pk域)。我知道,因为我将 ID 添加到 student_in_class 字段,所以我不应该将它用作 read_only = true
,但是我必须使用它,否则它会产生错误。如何解决这个问题?另外,我真的不知道在序列化器中定义哪些字段 class.
更新代码:
class TeacherSerializer(serializers.ModelSerializer):
# students_in_class = serializers.PrimaryKeyRelatedField(
# many = True, read_only= True
# )
students_in_class = serializers.ListField(
source="students_in_class.all",
child=serializers.PrimaryKeyRelatedField(queryset=Student.objects.all()),
)
address = serializers.CharField(required=False)
# user = serializers.PrimaryKeyRelatedField(read_only=True)
class Meta:
model = Teacher
fields = ["address","students_in_class"]
# fields = '__all__'
def update(self, instance, validated_data):
instance.address = validated_data['students_in_class']['all']
instance.save()
stu = validated_data.get("students_in_class")
print(stu)
if stu is not None:
print("iam stu")
instance.students_in_class.add(stu)
instance.save()
super(TeacherSerializer,self).update(instance, validated_data)
return instance
由于您使用的是 m2m 字段,因此您需要 students_in_class
的 ID 列表。所以解决方案将是这样的。 (免责声明:代码未经测试)。
class TeacherSerializer(serializers.ModelSerializer):
students_in_class = serializers.ListField(
source="students_in_class.all",
child=serializers.PrimaryKeyRelatedField(queryset=Student.objects.all()),
)
序列化错误将得到解决,因为现在您已将 students_in_class.all
作为来源。您需要像这样访问数据:validated_data['students_in_class']['all']
如果您想以不同的方式序列化您的输出,您可以将 students_in_class
设置为 write_only
并根据需要覆盖序列化程序表示。:
class TeacherSerializer(serializers.ModelSerializer):
students_in_class = serializers.ListField(
child=serializers.PrimaryKeyRelatedField(queryset=Student.objects.all()),
write_only=True
)
# your code
def to_representation(self, instance):
ret = super().to_representation(instance)
ret['students_in_class'] = StudentSerializer(instance.students_in_class.all(), many=True).data
return ret
以下代码有效:
class TeacherSerializer(serializers.ModelSerializer):
students_in_class = serializers.PrimaryKeyRelatedField(
many = True,queryset=Student.objects.all()
)
address = serializers.CharField(required=False)
class Meta:
model = Teacher
fields = ["address","students_in_class"]
def update(self, instance, validated_data):
instance.address = validated_data.get("address")
instance.save()
stu = validated_data.pop("students_in_class")
for stus in stu:
instance.students_in_class.add(stus)
instance.save()
super(TeacherSerializer,self).update(instance, validated_data)
return instance