Support custom model object keys

Hey, thanks for your work on this project. I was investigating integrating it with our EmberJS app but I ran into an issue. We have an Employee model that has a normal integer primary key, but also a username attribute. I’d like to only expose the username as the primary key, using DRF this is simple:

class EmployeeSerializer(serializers.ModelSerializer):
    id = serializers.ReadOnlyField(source="user.username")
    ...

However in build_json_resource_obj it just uses instance.pk:

def build_json_resource_obj(fields, resource, resource_instance, resource_name):
    resource_data = [
        ('type', resource_name),
        ('id', encoding.force_text(resource_instance.pk) if resource_instance else None),
        ...

Can you use the serializers ID field if available, and fallback to the instances PK?

[mblayman]

I am overjoyed to keep this discussion technical. 😄

My last comment was to provide an update about what’s going on with the maintainers so everyone has context of the project’s status. I’m happy to get back on track with the problem reported in this issue.

[wakingyeung]

If the fields parameter of build_json_resource_obj method contains an id field, use this id field, otherwise use the default implementation. I think this is very flexible.