How we can use model objects in ModelSerializer? - django

Question

I have to create an endpoint to make a customer subscribes to a chef.
The subscription model has two FK fields chef and customer.
model/subscriptionSerializer:
class Subscription(models.Model):
chef = models.ForeignKey(Chef, on_delete=models.CASCADE, db_column="chef")
customer = models.ForeignKey(User, on_delete=models.CASCADE, db_column="customer")
I created this serializer:
class SubscriptionSerializer(serializers.ModelSerializer):
chef = serializers.SerializerMethodField("get_chef")
customer = serializers.SerializerMethodField("get_customer")
class Meta:
model = Subscription
fields = [
"id",
"chef",
"customer",
]
def get_chef(self, *args):
return Chef.objects.get(pk=self.context.get("chef"))
def get_customer(self, *args):
return User.objects.get(pk=self.context.get("customer"))
I want to have one endpoint like this: customer/chef/<int:chef_id>/subscribe
So in view.py I used ModelViewSet:
class CustomerSubscribeChefView(viewsets.ModelViewSet):
permission_classes = (permissions.IsAuthenticated,)
serializer_class = SubscriptionSerializer
def get_serializer_context(self):
context = super(CustomerSubscribeChefView, self).get_serializer_context()
context.update({"chef": self.kwargs['chef_id']})
context.update({"customer": self.request.user.id})
return context
def get_queryset(self):
return self.request.user.subscription_set
def create(self, request, *args, **kwargs):
serializer = self.get_serializer(data=request.data)
serializer.is_valid(raise_exception=True)
self.perform_create(serializer)
return Response(
{"msg": "Chef is subscribed!"}, status=status.HTTP_201_CREATED
)
def destroy(self, request, *args, **kwargs):
instance = self.get_object()
self.perform_destroy(instance)
return Response({"msg": "Chef is unsubscribed!"}, status=status.HTTP_200_OK)
when I try to send a post request I got this error:
django.db.utils.IntegrityError: NOT NULL constraint failed: core subscription. chef _id
I've tried to use my custom serializer so I've updated SubscriptionSerializer to be like this:
class SubscriptionSerializer(serializers.ModelSerializer):
chef = ChefListSerializer
customer = CustomerSerializer
class Meta:
model = Subscription
fields = [
"id",
"chef",
"customer",
]
But I don't know how to serialize chef and customer objects.
What is the problem with my approach, and how I can fix this?
Update
I changed the subscription serializer to be like this
class SubscriptionSerializer(serializers.ModelSerializer):
chef = Chef()
customer = User()
def __init__(self, *args, **kwargs):
context = kwargs.pop('context')
self.chef = Chef.objects.get(pk=context.get("chef"))
self.customer = User.objects.get(pk=context.get("customer"))
super().__init__(*args, **kwargs)
class Meta:
model = Subscription
fields = ["id", "chef", "customer"]
But I still get the same error.