Custom GET "action" endpoint not displaying query params

Describe the bug Query params don’t show up in an “@action” that doesn’t take a list serializer class.

I understand the point of view here of query params being for listing resources, but I’d like to know if there’s any way to bypass this check to load the query params anyway.

To Reproduce

This won’t display query params.

class UserViewSet(GenericViewSet, ListModelMixin):
    filterset_class = FilterSetClass

    @action(
        detail=False,
        methods=["GET"],
        # Using this serializer solely to display correct output
        serializer_class=NonListSerializer,
    )
    def export_csv(...):
        # Use query params to setup an async job
        return Response({"job_id": <uuid>})

Expected behavior Should display query params correctly.

After a quick look at the code, seems like if if is_list_serializer(serializer) and if hasattr(self.view, 'action') happen after if isinstance(self.view, ListModelMixin) at drf_spectacular.openapi.AutoSchema._is_list_view, then it’d render the query params alright.

[jourdanrodrigues]

Thanks for the clarification, @tfranzel! I finally managed to get it working. I actually made a mistake in that PR I sent. Here’s the snipper for historical purpose:

from drf_spectacular.extensions import OpenApiFilterExtension
from drf_spectacular.openapi import AutoSchema as SpectacularAutoSchema


class AutoSchema(SpectacularAutoSchema):
    def _get_filter_parameters(self):
        if not (self._is_a_general_list_view() or self._is_list_view()):
            return []
        if getattr(self.view, 'filter_backends', None) is None:
            return []

        parameters = []
        for filter_backend in self.view.filter_backends:
            filter_extension = OpenApiFilterExtension.get_match(filter_backend())
            if filter_extension:
                parameters += filter_extension.get_schema_operation_parameters(self)
            else:
                parameters += filter_backend().get_schema_operation_parameters(self.view)
        return parameters

    def _is_a_general_list_view(self):
        return hasattr(self.view, "detail") and self.method.lower() == "get" and not self.view.detail

[tfranzel]

https://github.com/tfranzel/drf-spectacular/blob/deb83250f078ed4bce17b12972e098409ac69ec9/drf_spectacular/openapi.py#L367

is where you would insert something that bypasses self._is_list_view() for your specific filterset class. i would not touch is_list_view itself but rather bypass that return [] only in your specific case emerges.