OpenAPI AutoSchema manual_fields

[illing2005]

The AutoSchema class for OpenAPI does not have a get_manual_fields method like coreapi implementation used to have it.
What is the best practive of adding manual fields to a schema?

[carltongibson]

When you say "manual fields", what do you want to add, exactly?

[illing2005]

Let's say I have a APIView that does not use any serializer or filters, but requires a parameter foo.
AutoSchema can't discover this parameter and I want to add it manually to the schema:

class MyView(APIView):
    # That's how it worked with coreapi.AutoSchema
    schema = AutoSchema(
        manual_fields=[
            coreapi.Field(
                    "foo",
                    location="query",
                    schema=coreschema.String(),
                ),
        ]
    )

    def get(self, request):
        # how can I tell AutoSchema to add foo to the schema?
        foo = request.query_params.get("foo")
        ...

[carltongibson]

Define an AutoSchema subclass and add the parameter in get_operation().

Something like:

from rest_framework.schemas.openapi import AutoSchema

class CustomSchema(AutoSchema):
    def get_operation(self, path, method):
        op = super().get_operation(path, method)
        operation['parameters'].append({
            "name": "foo",
            "in": "query",
            "required": True,
            "description": "What foo does...",
            'schema': {'type': 'string'}
        )
        return op

Should do you.

[illing2005]

Thanks!
Is there any reason why this feature is not available in AutoSchema?
It seems like very common use case to me

[carltongibson]

More or less, the two lines saved aren't, on balance worth the extra API surface area. Just subclass.