@extend_schema has no effect on GET/retrieve extra actions in a ModelViewSet

DRF v3.11.1 drf-spectacular v0.15.0

When adding an extra GET action (not merely overriding create or retrieve) in a ModelViewSet and decorating it with @extend_schema, the specified request serializer is not represented as a component in the generated schema.

In the example below, the search/ endpoint shows up under paths, but the fields under SearchRequestSerializer are not included under components/schemas. Changing the action to a POST method instead of a GET resolves the issue, but I believe the method really should be a GET.

Example View and method:

  class MyObjectViewSet(viewsets.ModelViewSet):

    http_method_names = ['get', 'post']
    serializer_class = MyObjectSerializer

    
    @sensitive_variables('access_token')
    @extend_schema(
        request=SearchRequestSerializer,
        responses={
            (200,'application/gzip'): OpenApiTypes.BINARY,
            401: OpenApiResponse(response=GeneralResponseSerializer),
            404: OpenApiResponse(response=GeneralResponseSerializer)
        },
    )
    @action(detail=False, methods=['GET'])
    def search(self, request):
      data = SearchRequestSerializer(data=self.request.query_params)
      data.is_valid(raise_exception=True)

      ...

      return response

Excerpt from the generated schema (as a GET):

paths:
/api/documents/search/:
    get:
      operationId: documents_search_retrieve
      tags:
      - documents
      security:
      - basicAuth: []
      - tokenAuth: []
      - {}
      responses:
        '200':
          content:
            application/gzip:
              schema:
                type: string
                format: binary
          description: ''
        '401':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GeneralResponse'
          description: null
        '404':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GeneralResponse'
          description: null

Excerpt from the generated schema (if I change it to a POST):

  /api/documents/search/:
    post:
      operationId: documents_search_create
      tags:
      - documents
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/SearchRequest'
          application/x-www-form-urlencoded:
            schema:
              $ref: '#/components/schemas/SearchRequest'
          multipart/form-data:
            schema:
              $ref: '#/components/schemas/SearchRequest'
        required: true
      security:
      - basicAuth: []
      - tokenAuth: []
      - {}
      responses:
        '200':
          content:
            application/gzip:
              schema:
                type: string
                format: binary
          description: ''
        '401':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GeneralResponse'
          description: null
        '404':
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GeneralResponse'
          description: null

...

components:
  schemas:
    SearchRequest:
      <details from the SearchRequest serializer>

I would expect a componentcalled SearchRequest to be included in the schema, along with the field metadata defined in SearchRequestSerializer.

I realize I may be misunderstanding the expected behavior here. If so, I could really use a pointer in the right direction.

[cantus-firmus]

Yes it does- thank you very much! I didn’t understand the distinction between the request and parameters args and how they correlate to the HTTP structures.

I assumed versions would be more tightly coupled, but I’ll go ahead and update in my dev environment today.

Thanks for your help!

[tfranzel]

Thanks for the reply. Updating to a newer release of drf is in our roadmap.

you can update spectacular regardless. Our latest version supports DRF>=3.10.4 which is clearly the case for your DRF version.