Attempting to Implement PolymorphicSerializer

launch_viewset.py

from django_filters.rest_framework import DjangoFilterBackend
from drf_spectacular.utils import OpenApiParameter, extend_schema, extend_schema_view
from rest_framework.filters import OrderingFilter, SearchFilter

from api.endpoints.common.views import BaseModelViewSet
from api.models import Launch
from api.permission import HasGroupPermission

from ...common.prefetches import get_prefetched_launch_queryset
from ...launch.filters import LaunchFilterSet
from ...launch.serializers import LaunchDetailedSerializer, LaunchListSerializer, LaunchSerializerCommon
from .common import check_common_filters

from drf_spectacular.utils import PolymorphicProxySerializer

polymorphic_serializer = PolymorphicProxySerializer(
    component_name="MetaLaunch",
    serializers=[LaunchListSerializer, LaunchSerializerCommon],
    resource_type_field_name="type",
)

poly_extend = extend_schema(
    responses={
        200: polymorphic_serializer,
    },
    parameters=[
        OpenApiParameter(
            name="lsp__name",
            type=str,
            location=OpenApiParameter.QUERY,
        ),
        OpenApiParameter(
            name="lsp__id",
            type=int,
            location=OpenApiParameter.QUERY,
        ),
        OpenApiParameter(
            name="related",
            type=bool,
            location=OpenApiParameter.QUERY,
            description="Include related agencies in the lsp__name and lsp__id filters.",
        ),
        OpenApiParameter(
            name="location__ids",
            type=int,
            many=True,
            location=OpenApiParameter.QUERY,
        ),
        OpenApiParameter(
            name="lsp__ids",
            type=int,
            many=True,
            location=OpenApiParameter.QUERY,
        ),
        OpenApiParameter(
            name="pad__ids",
            type=int,
            many=True,
            location=OpenApiParameter.QUERY,
        ),
        OpenApiParameter(
            name="strict_filtering",
            type=bool,
            location=OpenApiParameter.QUERY,
            description="Enforce strict filtering for lsp__ids, location__ids, and pad__ids. "
            "False by default for backwards-compatibility.",
        ),
    ],
)


@extend_schema_view(
    list=poly_extend,
    retrieve=poly_extend,
)
class LaunchViewSet(BaseModelViewSet):
    """
    AN API endpoint that returns all Launch objects or a single launch.

    EXAMPLE - /launch/\<id\>/ or /launch/?mode=list&search=SpaceX

    GET
    Return a list of all Launch objects.

    FILTERS
    Fields - 'name', 'id(s)', 'lsp__id', 'lsp__name', 'serial_number', 'launcher_config__id',
     'rocket__spacecraftflight__spacecraft__name', 'is_crewed', 'include_suborbital', 'spacecraft_config__ids',
     'related', 'location__ids', 'lsp__ids', 'pad__ids', 'status__ids'

    MODE
    'normal', 'list', 'detailed'

    EXAMPLE ?mode=list

    SEARCH
    Searches through the launch name, rocket name, launch agency, mission name & spacecraft name.

    EXAMPLE - ?search=SpaceX
    """

    def get_queryset(self):
        lsp_name = self.request.query_params.get("lsp__name", None)
        lsp_id = self.request.query_params.get("lsp__id", None)
        location_filters = self.request.query_params.get("location__ids", None)
        lsp_filters = self.request.query_params.get("lsp__ids", None)
        related = self.request.query_params.get("related", None)
        pad_filters = self.request.query_params.get("pad__ids", None)
        strict = self.request.query_params.get("strict_filtering", None)

        launches = Launch.objects.all()

        launches = check_common_filters(
            launches,
            location_filters,
            lsp_filters,
            lsp_id,
            lsp_name,
            pad_filters,
            related,
            strict,
        )

        mode = self.request.query_params.get("mode", "normal")
        return (
            get_prefetched_launch_queryset(launches, mode == "detailed")
            .order_by("net", "net_precision", "name")
            .distinct()
        )

    def get_serializer_class(self):
        mode = self.request.query_params.get("mode", "normal")
        if self.action == "retrieve" or mode == "detailed":
            return LaunchDetailedSerializer
        elif mode == "list":
            return LaunchListSerializer
        else:
            return LaunchSerializerCommon

    permission_classes = [HasGroupPermission]
    permission_groups = {"retrieve": ["_Public"], "list": ["_Public"]}
    filter_backends = (DjangoFilterBackend, SearchFilter, OrderingFilter)
    filter_class = LaunchFilterSet
    search_fields = (
        "name",
        "rocket__configuration__name",
        "rocket__configuration__manufacturer__name",
        "launch_service_provider__name",
        "rocket__configuration__manufacturer__abbrev",
        "mission__name",
        "pad__location__name",
        "pad__name",
        "rocket__spacecraftflight__spacecraft__name",
    )
    ordering_fields = (
        "id",
        "name",
        "net",
        "last_updated",
    )
    http_method_names = ["get"]

serializers.py

class LaunchListSerializer(serializers.ModelSerializer):
    pad = serializers.StringRelatedField(source="pad.name")
    location = serializers.StringRelatedField(source="pad.location")
    status = LaunchStatusSerializer(many=False, read_only=True)
    net_precision = NetPrecisionSerializer(many=False, read_only=True)
    landing = serializers.SerializerMethodField()
    landing_success = serializers.SerializerMethodField()
    launcher = serializers.SerializerMethodField()
    orbit = serializers.SerializerMethodField()
    mission = serializers.StringRelatedField()
    image = serializers.SerializerMethodField()
    infographic = serializers.SerializerMethodField()
    mission_type = serializers.StringRelatedField(source="mission.mission_type.name")
    slug = serializers.SlugField(source="get_absolute_url")
    lsp_name = serializers.StringRelatedField(source="launch_service_provider.name")

    type = serializers.SerializerMethodField()

    class Meta:
        model = Launch
        fields = (
            "id",
            "url",
            "slug",
            "name",
            "status",
            "last_updated",
            "net",
            "net_precision",
            "window_end",
            "window_start",
            "lsp_name",
            "mission",
            "mission_type",
            "pad",
            "location",
            "landing",
            "landing_success",
            "launcher",
            "orbit",
            "image",
            "infographic",
            "type"
        )

    def get_type(self, obj) -> str:
        return 'list'
    
 ...


class LaunchSerializerCommon(serializers.HyperlinkedModelSerializer):
    pad = PadSerializer(many=False, read_only=True)
    rocket = RocketSerializerCommon(many=False, read_only=True)
    mission = MissionSerializer(many=False, read_only=True)
    status = LaunchStatusSerializer(many=False, read_only=True)
    net_precision = NetPrecisionSerializer(many=False, read_only=True)
    slug = serializers.SlugField(source="get_absolute_url")
    launch_service_provider = AgencySerializerMini(read_only=True)
    program = ProgramSerializer(many=True, read_only=True)

    image = serializers.SerializerMethodField()
    infographic = serializers.SerializerMethodField()

    type = serializers.SerializerMethodField()

    class Meta:
        depth = 3
        model = Launch
        fields = (
            "id",
            "url",
            "slug",
            "name",
            "status",
            "last_updated",
            "net",
            "window_end",
            "window_start",
            "net_precision",
            "probability",
            "weather_concerns",
            "holdreason",
            "failreason",
            "hashtag",
            "launch_service_provider",
            "rocket",
            "mission",
            "pad",
            "webcast_live",
            "image",
            "infographic",
            "program",
            "orbital_launch_attempt_count",
            "location_launch_attempt_count",
            "pad_launch_attempt_count",
            "agency_launch_attempt_count",
            "orbital_launch_attempt_count_year",
            "location_launch_attempt_count_year",
            "pad_launch_attempt_count_year",
            "agency_launch_attempt_count_year",
            "type"
        )

    def get_type(self, obj) -> str:
        return 'normal'

...