serializers.py

        return v

    def validate_library(self, v):
        lb = self.context.get("library")
        if lb:
            if lb.fid != v:
                raise serializers.ValidationError("Invalid library")
            return lb

        actor = self.context.get("actor")
        kwargs = {}
        if actor:
            kwargs["actor"] = actor
        try:
            return music_models.Library.objects.get(fid=v, **kwargs)
        except music_models.Library.DoesNotExist:
            raise serializers.ValidationError("Invalid library")

    def create(self, validated_data):
        try:
            return music_models.Upload.objects.get(fid=validated_data["id"])
        except music_models.Upload.DoesNotExist:
            pass

        track = TrackSerializer(
            context={"activity": self.context.get("activity")}
        ).create(validated_data["track"])

        data = {
            "fid": validated_data["id"],
            "mimetype": validated_data["url"]["mediaType"],
            "source": validated_data["url"]["href"],
            "creation_date": validated_data["published"],
            "modification_date": validated_data.get("updated"),
            "track": track,
            "duration": validated_data["duration"],
            "size": validated_data["size"],
            "bitrate": validated_data["bitrate"],
            "library": validated_data["library"],
            "from_activity": self.context.get("activity"),
            "import_status": "finished",
        }
        return music_models.Upload.objects.create(**data)

    def to_representation(self, instance):
        track = instance.track
        d = {
            "type": "Audio",
            "id": instance.get_federation_id(),
            "library": instance.library.fid,
            "name": track.full_name,
            "published": instance.creation_date.isoformat(),
            "bitrate": instance.bitrate,
            "size": instance.size,
            "duration": instance.duration,
            "url": {
                "href": utils.full_url(instance.listen_url),
                "type": "Link",
                "mediaType": instance.mimetype,
            },
            "track": TrackSerializer(track, context={"include_ap_context": False}).data,
        }
        if instance.modification_date:
            d["updated"] = instance.modification_date.isoformat()

        if self.context.get("include_ap_context", self.parent is None):
            d["@context"] = AP_CONTEXT
        return d


class NodeInfoLinkSerializer(serializers.Serializer):
    href = serializers.URLField()
    rel = serializers.URLField()


class NodeInfoSerializer(serializers.Serializer):
    links = serializers.ListField(child=NodeInfoLinkSerializer(), min_length=1)