Polymorphic related fields for tastypie

gistfile1.py

class PolymorphicRelatedField(fields.ToOneField):
        
    def get_related_resource(self, related_instance):
        """
        Instaniates the related resource.
        """
        to = {
            models.Asset: AssetResource,
            models.Content: ContentResource,
        }
        related_model = get_model(related_instance._meta.app_label, 
                           related_instance.__class__.__name__)
        related_resource = to[related_model]()
        # Fix the ``api_name`` if it's not present.
        if related_resource._meta.api_name is None:
            if self._resource and not self._resource._meta.api_name is None:
                related_resource._meta.api_name = self._resource._meta.api_name

        # Try to be efficient about DB queries.
        related_resource.instance = related_instance
        return related_resource