Change a field in a Django REST Framework ModelSerializer based on the request type?

Question

Consider this case where I have a Book and Author model.

serializers.py

class AuthorSerializer(serializers.ModelSerializer):

         


        

Answer 1

There is a feature of DRF where you can dynamically change the fields on the serializer http://www.django-rest-framework.org/api-guide/serializers/#dynamically-modifying-fields

My use case: use slug field on GET so we can see nice rep of a relation, but on POST/PUT switch back to the classic primary key update. Adjust your serializer to something like this:

class FooSerializer(serializers.ModelSerializer):
    bar = serializers.SlugRelatedField(slug_field='baz', queryset=models.Bar.objects.all())

    class Meta:
        model = models.Foo
        fields = '__all__'

    def __init__(self, *args, **kwargs):
        super(FooSerializer, self).__init__(*args, **kwargs)

        try:
            if self.context['request'].method in ['POST', 'PUT']:
                self.fields['bar'] = serializers.PrimaryKeyRelatedField(queryset=models.Bar.objects.all())
        except KeyError:
            pass

The KeyError is sometimes thrown on code initialisation without a request, possibly unit tests.

Enjoy and use responsibly.