Not being able to represent array serializer in get_serializer_class

[hnykda]

(moved here #8109)

Hey.

I want an endpoint that returns simple array of items of type Log. I am aware that when initializing that, I should use many=True. But to also nicely generate the docs, I want to somehow represent that in get_serializer_class:

class ProcessingJobViewSet(GenericViewSet):
    queryset = ProcessingJob.objects.all()
    serializer_class = ProcessingJobSerializer

    def get_serializer_class(self):
        if self.action == "logs":
            return LogSerializer
        return self.serializer_class

    @action(detail=True, url_path="logs")
    def logs(self, request: Request, pk: int) -> Response:
        job = self.get_object()
        logs = retrieve_logs(job)
        return Response(LogSerializer(logs, many=True).data)

But how should I do it given that it needs to return the class def, not its instance? If I try to return ListSerializer(child=LogSerializer) it complains about child not being initialized and when I do initialize it, then it complains about ListSerializer object not callable.

The only workaround I found is to do:

class LogsSerializer(serializers.Serializer):
  results = LogSerializer(many=True)

but then I have a useless results key in the response.

[hnykda]

Yeah, thanks, I know, but that doesn't get represented in docs in such way - OpenAPI schema will have only a single LogSerializer instead of Array[LogSerializer]. That's what I am looking forward to fix. The way how we workaround this is:

class ExtendedAutoSchema(AutoSchema):
    """
    Some endpoints have false auto-generated response as a single object
    instead of Array of objects. This class make it possible to
    fix these endpoints.
    @param array_endpoints: endpoints forced to show array of results
    """

    def __init__(self, array_endpoints: List[str] = None, **kwargs: Any):
        self.array_endpoints = array_endpoints
        super().__init__(**kwargs)

    def get_responses(self, path: str, method: str) -> Dict[str, Any]:
        orig = super().get_responses(path, method)
        if self.array_endpoints and any(
            map(lambda end: path.endswith(end + "/"), self.array_endpoints)
        ):
            json_response_content = orig["200"]["content"]["application/json"]
            json_response_content["schema"] = {
                "type": "array",
                "items": json_response_content["schema"],
            }
        return orig

and then in the view:

class ViewSet(...):
    schema = ExtendedAutoSchema(array_endpoints=["logs"])

[hnykda]

#8109