How to serialize relationship in django rest? - json

Question

Try to serialize this Models
Model:
class Order (models.Model):
id = models.AutoField(primary_key=True)
date_create = models.DateField(auto_now_add=True)
date_change = models.DateField(auto_now=True)
summ =models.CharField(max_length=15,default='0')
delivery = models.ForeignKey('Delivery')
success = models.BooleanField(default=False)
paymentMethod = models.ForeignKey('Payments')
def __unicode__(self):
return unicode(self.id)
class OrderProduct(models.Model):
order=models.ForeignKey('Order')
id = models.AutoField(primary_key=True)
date_create = models.DateField(auto_now_add=True)
date_change = models.DateField(auto_now=True)
price = models.IntegerField()
product = models.ForeignKey('product.Product')
additionals = models.IntegerField(null=True,default=0)
count = models.IntegerField()
def __unicode__(self):
return self.id
class Delivery(models.Model):
id = models.AutoField(primary_key=True)
date_create = models.DateField(auto_now_add=True)
date_change = models.DateField(auto_now=True)
delivery_time = models.DateTimeField()
delivery_adress = models.TextField()
phone = models.TextField()
def __unicode__(self):
return self.phone
class Payments(models.Model):
id = models.AutoField(primary_key=True)
date_create = models.DateField(auto_now_add=True)
date_change = models.DateField(auto_now=True)
title = models.TextField();
def __unicode__(self):
return self.title
Serializers:
class DeliverySerializer(serializers.ModelSerializer):
class Meta:
model = Delivery
fields = ('id', 'delivery_time','delivery_adress','phone')
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)
class OrderSerializer(serializers.ModelSerializer):
delivery = DeliverySerializer(read_only=True)
paymentMethod = PaymentsSerializer(read_only=True)
class Meta:
model = Order
fields = ('id', 'delivery', 'paymentMethod','summ','success')
def create(self, validated_data):
deliverys_data = validated_data.pop('delivery')
paymentsMethod_data = validated_data.pop('paymentMethod')
order = Order.objects.create(**validated_data)
for delivery_data in deliverys_data:
Delivery.objects.create(order=order, **delivery_data)
for paymentMethod_data in paymentsMethod_data:
Payments.objects.create(order=order, **paymentMethod_data)
return order
View:
#api_view(['POST'])
def order_post(request, format=None):
#List all snippets, or create a new snippet.
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)
I need to get data by 1 packet, and then write data in DB
EveryTime I get a error:
deliverys_data = validated_data.pop('delivery')
KeyError: 'delivery'
Example of JSON packet
[{"delivery":{"delivery_time":"2016-05-31T12:18:47Z","delivery_adress":"123","phone":"123"},"paymentMethod":{"id":1,"title":"123124123"},"summ":"23","success":false}]

Answer 1

You are getting KeyError: 'delivery' because you have set delivery field as read_only. If DRF finds this field in the input, it will ignore that field.
From docs on read_only argument:
Read-only fields are included in the API output, but should not be
included in the input during create or update operations. Any
'read_only' fields that are incorrectly included in the serializer
input will be ignored.
Also, since you are using paymentMethod field in the create() method, you need to tell DRF to consider that field also in the input.
So, you need to remove the read_only argument from your serializer for both delivery and paymentMethod fields so that these fields are considered when deserializing.
class OrderSerializer(serializers.ModelSerializer):
delivery = DeliverySerializer() # remove read_only argument
paymentMethod = PaymentsSerializer() # remove read_only argument
Secondly, you are sending the data incorrectly. You need to send a single order input instead of list of orders you are sending.
# send without the list
{"delivery":{"delivery_time":"2016-05-31T12:18:47Z","delivery_adress":"123","phone":"123"},"paymentMethod":{"id":1,"title":"123124123"},"summ":"23","success":false}

Answer 2

EveryTime I get a error: deliverys_data = validated_data.pop('delivery') KeyError: 'delivery'
This is to be expected since the OrderSerialzier has DeliverySerializer flagged as read_only.
If you want to get the data writable, you'll need to remove that flag first.