Can't assign related object in creation

[uripeled2]

from django.db import models


class Location(models.Model):
    city = models.CharField(max_length=100)


class Store(models.Model):
    name = models.CharField(max_length=100)
    location = models.ForeignKey(Location, on_delete=models.CASCADE, null=True)


class LocationSerializer(serializers.ModelSerializer):
         class Meta:
                 model = Location
                  fields = ('id', 'city')


class StoreSerializer(serializers.ModelSerializer):
    location = LocationSerializer(required=False, allow_null=True)
    
    class Meta:
        model = Store
       fields = ('id', 'name', 'location')



1. {
"name": "KFC",
"location": {"id": 1}
}

2. {
"name": "KFC",
"location": 1
}

The first request return:

{
    "location": {
            "city": [
                "This field is required."
        ]
    }
}

And the second raise TypeError: argument of type 'int' is not iterable

The first request works fine when I do patch/put

[smilerz]

I created an override for WritableNestedModelSerializer.to_internal_value() that I think is generalizable. This hasn't been exhaustively tested, so use at your own risk.

    def to_internal_value(self, data):
        def get_object(field, model, serializer, value):
            nested_obj = get_object_or_None(model, id=value)
            if nested_obj is not None:
                obj = serializer(nested_obj, context=self.context).data
                for key in list(serializer(nested_obj, context=self.context).data):
                    if key not in ['id'] + [field_name for field_name, field in serializer().fields.items() if field.required]:
                        obj.pop(key, None)
                return obj
            else:
                return value
        for f in list(data):
            if issubclass(self.fields[f].__class__, serializers.Serializer):
                if isinstance(data[f], int):
                    data[f] = get_object(f, self.fields[f].Meta.model, self.fields[f].__class__, data[f])
            elif issubclass(self.fields[f].__class__, serializers.ListSerializer):
                for idx, item in enumerate(data[f]):
                    if isinstance(item, int):
                        data[f][idx] = get_object(f, self.fields[f].child.Meta.model, self.fields[f].child.__class__, item)
        return super().to_internal_value(data)