Save nested object with serializer in django rest framework

Question

I'm getting a Json response to save it in my database, I need to get the items in line_items object. My Serializer and View works fine if I remove the line_items attribute in the model, but when I try to get that object and save it in the database nothing happens. Maybe I'm missing something in my serializer?

Json Structure:

{
    "id": 123456,
    "email": "[email protected]",
    "created_at": "2017-03-29T15:56:48-04:00",
    "line_items": [
        {
            "id": 56789,
            "title": "Aviator sunglasses",
            "quantity": 1
         },

    {
        "id": 98765,
        "title": "Mid-century lounger",
        "quantity": 1
    }

    ]
}

My model:

class Line(models.Model):
    title = models.CharField(max_length=100)
    quantity = models.IntegerField()


class Order(models.Model):
    name = models.CharField(max_length=255)
    created_at = models.DateTimeField()
    total_price = models.DecimalField(max_digits=6,decimal_places=2)
    line_items = models.ForeignKey(Line)

My Serializer:

class OrderSerializer(ModelSerializer):
    class Meta:
        model = Order
        fields = '__all__'

My View:

@api_view(['POST'])
def orders(request):
    if request.method == 'POST':
        json_str = json.dumps(request.data)
        resp = json.loads(json_str)
        serializer = OrderSerializer(data=request.data)
        if serializer.is_valid():
            serializer.save()
        return Response(serializer.data, status=status.HTTP_200_OK)

meshy · Accepted Answer · 2019-01-18 12:44:19Z

2

You have a list in the field-key line_items in your response, as per your models you can't accommodate the data in the tables, what you need is ManyToMany relation between Order and Line,

class Order(models.Model):
    name = models.CharField(max_length=255)
    created_at = models.DateTimeField()
    total_price = models.DecimalField(max_digits=6,decimal_places=2)
    line_items = models.ManyToManyField(Line)

and in your serializer,

class OrderSerializer(ModelSerializer):
    class Meta:
        model = Order
        fields = [f.name for f in model._meta.fields] + ['line_items']

    def create(self, validated_data):
        line_items = validated_data.pop('line_items')
        instance = super(OrderSerializer, self).create(validated_data)
        for item in line_items:
            instance.line_items.add(item['id'])
        instance.save()
        return instance

edited Jan 18, 2019 at 12:44

meshy

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answered Aug 7, 2017 at 9:31

zaidfazil

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Comments

pd farhad · Accepted Answer · 2017-08-07 09:16:14Z

1

Just add depth=1 in your serializer. It will do-

class OrderSerializer(ModelSerializer):

    class Meta:
        depth = 1
        fields = '__all__'

answered Aug 7, 2017 at 9:16

pd farhad

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Comments

Xiao · Accepted Answer · 2017-03-29 20:32:05Z

0

I think you should add an explicit line_items field to OrderSerializer. Like this:

class OrderSerializer(ModelSerializer):
    line_items = LineSerializer(many=True)
    class Meta:
        model = Order
        fields = '__all__'

answered Mar 29, 2017 at 20:32

Xiao

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2 Comments

dfrojas Over a year ago

thanks for your reply. Did not works, I think that would be something with the method create.

Xiao Over a year ago

line_items is a list in the post, but a foreign key in the model. I think it should be a ManyToManyField

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