Required Field type Issue

[lmregus]

Hello, I am building an integration with an external webhook, unfortunately the webhook returns 2 slightly different payloads depending if the payload has a collection of objects or not.

I am trying to use the OneOfSchema to allow my endpoint to support these 2 different schemas, but when I hit the endpoint it fails saying that it requires the type field, when I add the type field with the expected value it works fine, the problem with this is that I have no access to the real payload being created which means that I can not ask the third party service to add the type key with the expected value to the payload before sending it.

In code I have something like this:

@bp.route(
    f"/{RESOURCE}/endpoint"
)
class className(MethodView):
    @bp.arguments(OneOfSchemaClass)
    @bp.response(200)
    def post(self, data: dict):

Is this something that's not supported/achievable? Unless the type key is explicitly set in the incoming payload?

[lmregus]

Solved it with @pre_load

[lmregus]

I will re-open, because @pre_load does not work, is there any solutions for this? Or is it not expected to be used the way I am using it?