Django Rest Framework我不能使用具有外键的序列化器保存模型

Question

I'm a Django Rest Framework and Django newbie i can use random data to make stages but i can't use serializer to add new stages.

My model and serializer

class Stage(models.Model):
    class Meta:
        db_table = 'stage'
    stage_id = models.AutoField(primary_key=True)
    stage_name = models.CharField(max_length=64, null=False)
    company = models.ForeignKey(
        Company,
        db_column='id',
        on_delete=models.CASCADE,
    )
class StageSerializer(ModelSerializer):
    stage_id = IntegerField(read_only=True)
    class Meta:
        model = Stage
        fields = [
            'stage_id',
            'stage_name',
            'company',
        ]
    def update(self, instance, validated_data):
        pass
    def create(self, validated_data):
        # create stages
        stage = create_stage(**validated_data)
        return stage

view.py

class StageListAPIView(APIView):
    def post(self, request, company_id):
        data = request.data.copy()
        company = get_company_by_id(company_id)
        data['company'] = company.pk
        serializer = StageSerializer(data=data)
        if not serializer.is_valid(raise_exception=True):
            return Response(serializer.errors, status=HTTP_400_BAD_REQUEST)
        new_data = serializer.validated_data
        serializer.save(company=company)
        return Response(new_data, status=HTTP_200_OK)

request.data

<QueryDict: {'stage_name': ['kAkSdKq9Gt'], 'company': [6]}>

i will receive error: TypeError: Object of type Company is not JSON serializable

i can't understand it and i don't know how to use serializer to save foreign key.

Answer 1

You need to serialize the Company instance before you can include it in your StageSerializer .

A simple example would be something like

class CompanySerializer(ModelSerializer):

class Meta:
    model = Company
    fields = '__all__'

And then to include that in your StageSerializer :

class StageSerializer(ModelSerializer):
    stage_id = IntegerField(read_only=True)
    company = CompanySerializer(source='company', read_only=True)
    class Meta:
        model = Stage
        fields = [
            'stage_id',
            'stage_name',
            'company',
        ]