A part of JSON is lost when it is received in DjangoRest

Question

I send the following JSON:

{"delivery":{"delivery_time":"2016-05-31T12:18:47Z","delivery_adress":"123","phone":"123"},"paymentMethod":{"id":"1","title":"123124123"},"summ":"23","success":false}

Serializer:

 class OrderSerializer(serializers.ModelSerializer): delivery = DeliverySerializer(required=False, allow_null=True) paymentMethod = PaymentsSerializer(required=False, allow_null=True) class Meta: model = Order fields = ( 'delivery', 'paymentMethod','summ','success') #'id', def create(self, validated_data): deliverys_data = validated_data.pop('delivery') delivery = Delivery.objects.create(**deliverys_data) paymentsMethod_data = validated_data.pop('paymentMethod') data=list(paymentsMethod_data.values())[:3] print(data) payment_method = Payments.objects.create(**paymentsMethod_data) order = Order.objects.create(delivery=delivery,paymentMethod=payment_method,**validated_data) return order

I try to get an id so that I can use it in Object ordere using Object get, and not create a new one every time, but each time I get only: [u'123124123 '], given only by name. At the moment, the order is created but each time creating new methods of payment

And I do not understand where he goes

View

 @api_view(['POST']) def order_post(request, format=None): if request.method == 'POST': serializer = OrderSerializer(data=request.data) if serializer.is_valid(): serializer.save() return Response(serializer.data, status=status.HTTP_201_CREATED) return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)

Other serializers

 class DeliverySerializer(serializers.ModelSerializer): class Meta: model = Delivery fields = ('delivery_time','delivery_adress','phone')#'id', def create(self, validated_data): return Delivery.objects.create(**validated_data) class PaymentsSerializer(serializers.ModelSerializer): class Meta: model = Payments fields = ('id','title') # def create(self, validated_data): return Payments.objects.create(**validated_data)

Answer 1 · 2016-06-10T16:00:56

When you pass information about a payment method, the serializer ignores the id field — it is read-only. And since the instance argument is not passed to the serializer, it creates a new payment method using the create method.

If you do not need to change the payment method, paymentMethod = PaymentsSerializer(required=False, allow_null=True) must be removed. Then the field will only accept the id of the existing payment methods. The request will be as follows:

 { "delivery": { "delivery_time":"2016-05-31T12:18:47Z", "delivery_adress":"123", "phone":"123" }, "paymentMethod": "1", "summ":"23", "success":false }

But the answer will also return the id. If you need a different behavior, you will need the logic of OrderSerializer or PaymentsSerializer.

{"delivery": {"delivery_time": "2016-05-31T12: 18: 47Z", "delivery_adress": "123", "phone": "123"}, "paymentMethod": "1", "summ" : "23", "success": false} I’m sending this request, everything looks fine

Dunaevsky Maxim Dunaevsky Maxim 131 6 · Answer 2 · 2016-07-03T07:19:21

For such cases, several serializers are created, usually three:

list serializer that contains only the minimum required number of fields
serializer for a detailed view of the record
record creation / update serializer

If you follow this logic, then you should have something like this code (in general):

app.serializers.py

 from rest_framework.serializers import ModelSerializer from rest_framework.serializers import PrimaryKeyRelatedField from .models import ModelClass from anothermodel.models import AnotherModel # Связанная модель from anothermodel.serializers import AnotherModelListSerializer class ModelListSerializer(ModelSerializer): """ Сериализатор для списка. Как правило, в списках нужно выводить только общие свойства модели, а внешние ключи можно и вовсе спрятать """ class Meta: model = ModelClass exclude = [ "related_model" ] # Внешний ключ, сейчас его не нужно сериализовать class ModelDetailSerializer(ModelSerializer): """ Сериализатор для детальной информации о записи. Поле related_field будет сериализовано, и на клиенте мы увидим JSON-объект с вложенными полями. """ related_model = AnotherModelListSerializer() class Meta: model = ModelClass class ModelWriteSerializer(ModelSerializer): """ Сериализатор для создания/обновления модели. С клиента нужно передавать только id для модели, с которой будет связано поле related_field. Параметр queryset указывает набор объектов, с которыми можно выполнить связь. """ related_model = PrimaryKeyRelatedField( queryset=AnotherModel.objects.all(), write_only=True ) class Meta: model = ModelClass

Now somewhere in the description of the form:

api.movelviews

 from app.models import ModelClass from rest_framework.viewsets import ModelViewSet from app.serialziers import ModelListSerializer, ModelDetailSerializer, ModelWriteSerializer class ModelClassViewSet(ModelViewSet): queryset = ModelClass.objects.all() # а можно и get_queryset переопределить def get_serializer_class(self): if self.request.method == "GET": if self.action == "list": return ModelListSerializer # GET: /api/models/ return ModelDetailSerializer # GET: /api/models/:id/ return ModelWriteSerializer # POST, PUT, etc к /api/models/ и /api/models/:id/ class Meta: model = ModelClass

Thanks, interesting, now I will try to implement in practice
I send 1 JSON to the server and I want to write it to different models
Delivery.objects.create () works as a forced creation of a model and storing it in the database.
Read more here: docs.djangoproject.com/en/dev/ref/models/querysets/…
In other words, each time calling your serializer will create a new entry.
Instead, you should use the function get_or_create - if there is no record in the database, Django will automatically create it: docs.djangoproject.com/en/1.9/ref/models/querysets/…

A part of JSON is lost when it is received in DjangoRest

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