Django : handle post JSON requests

Question

I need to handle some JSON data with django. I will receive this data:

{
    "user": 8,
    "orderDay": "2020-06-24",
    "deliveryDay": "2020-06-30",
    "deliveryAddress": "Place des Fêtes",
    "comment": "",
    "orderDetail": 
    [
        {
            "product": 2,
            "byProduct": 2,
            "quantity": 43
        },
        {
            "product": 3,
            "byProduct": 3,
            "quantity": 5
        }
    ]
}

I would like to save this data in 3 differents table: order and orderDetail . models.py :

class order(models.Model):
    user = models.ForeignKey(memberArea, on_delete=models.CASCADE)
    comment = models.TextField(null=True, blank=True)
    orderDay = models.DateTimeField(auto_now_add=True)
    deliveryDay = models.DateField()
    deliveryPlace = models.CharField(max_length=255)
    state = models.CharField(max_length=255)
    price = models.TextField(null=True, blank=True)
    response = models.TextField(null=True, blank=True)
...
class orderDetail(models.Model):
    order = models.ForeignKey(order, on_delete=models.CASCADE)
    product = models.ForeignKey(product, on_delete=models.CASCADE)
    byProduct = models.ManyToManyField(byProduct)
    quantity = models.CharField(max_length=255)
...
class byProduct(models.Model):
    product = models.ForeignKey(product, on_delete = models.CASCADE)
    name = models.CharField(max_length=255)
...
class product(models.Model):
    name = models.CharField(max_length=255)
    prix_uni = models.TextField(null=True, blank=True)
    prix_kg = models.TextField(null=True, blank=True)
    dispo = models.BooleanField(null=True, blank=True)
    category = models.ForeignKey(category, on_delete=models.CASCADE)
    redu = models.TextField(null=True, blank=True)

I don't find any good documentation about how to handle JSON data whith Django. Thanks by advance

UPDATE

I tried something like this: serializer.py :

class ProductSerializer(serializers.ModelSerializer):
    class Meta:
        model = product
        fields = '__all__'

class ByProductSerializer(serializers.ModelSerializer):
    class Meta:
        model = byProduct
        fields = '__all__'

class orderDetailSerializer(serializers.ModelSerializer):

    order = serializers.PrimaryKeyRelatedField(many=False, queryset=order.objects.all())

    class Meta:
        model = orderDetail
        fields = '__all__'

class OrderSerializer(serializers.ModelSerializer):

    orderDetail = orderDetailSerializer(many=True)

    class Meta:
        model = order
        fields = ['user', 'comment', 'deliveryDay', 'deliveryAddress', 'orderDetail']

    def create(self, validated_data):
            order_detail_data = validated_data.pop('orderDetail')
            new_order = order.objects.create(**validated_data)
            new_order.save()
            for product in order_detail_data:
                order_detail = orderDetail.objects.create(**product)
                order_detail.order.add(new_order.id)
            
            return new_order

views.py :

@api_view(['POST'])
def order(request, format=None):
    if request.method == 'POST':
        serializer = OrderSerializer(data=request.data)
        data = {}
        if serializer.is_valid():
            serializer.save()
            data['response'] = "Your order went well"
            return Response(data)
        return Response(serializer.errors)

Answer 1

There are few changes you need to make.

1. Change your data format:

{
    "user": 8,
    "orderDay": "2020-06-24",
    "deliveryDay": "2020-06-30",
    "deliveryAddress": "Place des Fêtes",
    "comment": "",
    "orderDetail": 
    [
        {
            "product": 2,
            "byProduct": [2],
            "quantity": 43
        },
        {
            "product": 3,
            "byProduct": [3],
            "quantity": 5
        }
    ]
}

byProduct is a ManyToMany field so it must have a list of products.

2. In your orderDetailSerializer :

class orderDetailSerializer(serializers.ModelSerializer):

    class Meta:
        model = orderDetail
        fields = ['product', 'byProduct', 'quantity']

Take note, in fields I have not included order because in our data there is no such field, and hence the error, order field is required . It's simple because serializer will parse the data we are sending and if there is something missing it will notify us.

3. Changes in orderSerializer :

class OrderSerializer(serializers.ModelSerializer):

    orderDetail = orderDetailSerializer(many=True)

    class Meta:
        model = order
        fields = ['user', 'comment', 'deliveryAddress', 'deliveryDay', 'orderDetail']

    def create(self, validated_data):
            order_detail_data = validated_data.pop('orderDetail')
            new_order = order.objects.create(**validated_data)
            # new_order.save()
            for product in order_detail_data:
                by_products = product.pop('byProduct')
                order_detail = orderDetail.objects.create(order=new_order, **product)
                order_detail.byProduct.set(by_products)
                order_detail.save()

            return new_order

Few things to notice, fields include orderDetail although it is not a part of order model, but in order to parse the data being passed we need to add such fields, if there are more. Inside create method byProduct is a ManyToMany field, so we will have to use set() method in order assign them, direct assignment is not allowed.