Help needed with serializing generic relation in DRF

[C aswin]

I am trying to learn how to use GenericRelations in Django-Rest-Framework. I found the documetation page for serializer relations and followed the codes. I created the models:

class TaggedItem(models.Model): """ Tags arbitary model instance using a generic relation. """ tag_name = models.SlugField() content_type = models.ForeignKey(ContentType) object_id = models.PositiveIntegerField() tagged_object = GenericForeignKey('content_type', 'object_id') def __unicode__(self): return self.tag_name class Bookmark(models.Model): """ A bookmark consists of a URL, and 0 or more descriptive tags. """ link_url = models.URLField() tags = GenericRelation(TaggedItem) class Note(models.Model): """ A note consists of some texts, and 0 or more descriptive tags """ text = models.CharField(max_length=1000) tags = GenericRelation(TaggedItem)

I created the serializers:

class BookmarkSerializer(serializers.ModelSerializer): class Meta: model = Bookmark fields = ('url', 'link_url', ) class NoteSerializer(serializers.ModelSerializer): class Meta: model = Note fields = ('url', 'text', ) class TaggedObjectRelatedField(serializers.RelatedField): """ A custom field to use for the 'tagged_object' generic relationship """ def to_representation(self, value): """ Serialize tagged objects to their respective serializer formats :param value: :return: serializer.data """ if isinstance(value, Bookmark): return 'Bookmark: ' + value.url elif isinstance(value, Note): return 'Note: ' + value.text raise Exception('Unexpected type of tagged object') class TaggedItemSerializer(serializers.ModelSerializer): tagged_object = TaggedObjectRelatedField() class Meta: model = TaggedItem fields = ('url', 'id', 'tag_name', 'tagged_object')

Now what should be the input to the TaggedObjectRelatedField() inside TaggedItemSerializer? Currently I am getting error as

 File "/home/aswin/Documents/WebProjects/drf_practice/uni_auth//loginpage/login/serializers.py", line 76, in TaggedItemSerializer tagged_object = TaggedObjectRelatedField() File "/home/aswin/Documents/WebProjects/drf_practice/uni_auth/lib/python3.5/site-packages/rest_framework/relations.py", line 80, in __init__ 'Relational field must provide a `queryset` argument, ' AssertionError: Relational field must provide a `queryset` argument, override `get_queryset`, or set read_only=`True`.

I tried giving the arguments as read_only=True too but it threw the same error.just to put what i exactly did:

class TaggedItemSerializer(serializers.ModelSerializer): tagged_object = TaggedObjectRelatedField(read_only=True)

Please help me with this. I am using django 1.9 and drf 3.4