Rest Framework deserialize one field and serialize model object - django

Question

Hi I want to deserialize only using 1 field. However, I want to serialize it as an object depending on the model.
Suppose I have:
#models.py
class Product(models.Model):
name = models.CharField()
amount = models.IntegerField()
description = models.TextField()
class Query(models.Model):
name = models.CharField()
product = models.ForeignKey(Product)
...
#serializers.py
class ProductSerializer(serializers.ModelSerializer):
class Meta:
model = Product
fields = '__all__'
class QuerySerializer(serializers.ModelSerializer):
product = ProductSerializer()
class Meta:
model = Query
fields = '__all__'
I want to POST/deserialize something like this on the QuerySerializer:
{
"name": "Query 1",
"product": "Banana",
...
}
and I want something like this in return for serializer:
{
"name": "Query 1",
"product": {
"name": "Banana",
"amount": 1,
"description": "Banana description"
}
...
}
I know a way is overriding to_internal_value but I do not like it since it messes up with ValidationErrrors.
I also get this as a result:
{'product': {'non_field_errors':
['Invalid data. Expected a dictionary, but got str.']}}

Answer 1

First of all, make the name field of Product as unique to avoid unnecessary complications.
class Product(models.Model):
name = models.CharField(unique=True)
amount = models.IntegerField()
description = models.TextField()
and change your serializer as,
class QuerySerializer(serializers.ModelSerializer):
product = serializers.CharField(write_only=True)
class Meta:
model = Query
fields = '__all__'
def create(self, validated_data):
product_name = validated_data.pop('product')
product_instance = Product.objects.get(name=product_name)
return Query.objects.create(product=product_instance, **validated_data)
def to_representation(self, instance):
rep = super().to_representation(instance)
rep['product'] = ProductSerializer(instance.product).data
return rep
Reference: DRF: Simple foreign key assignment with nested serializers?