referencing a json-schema from openapi3

Start with factories.py:SpecFactory:create and reproduce the failure using the provided test.yaml and test.json examples. Check how openapi_spec_validator handles the external $ref and review the linked OpenAPI Schema Object reference. Done means documenting or implementing the supported handling for this reference, including whether client-side validation can be bypassed.

Hello,

I am currently in the process of creating a python based REST api. I wrote an openapi 3.0 interface that reference an external json-schema file using $ref: 'test.json' (openapiref)[https://github.com/OAI/OpenAPI-Specification/blob/master/versions/3.0.0.md#schemaObject] as I thought this is supposed to be possible.

Now I wanted to use openapi-core to validate requests and responses but I hit a problem which is that the validation of my openapi interface file does not go through because I get an error of type:

{'description': 'some external json', 'content': {'application/json': {'schema': {'$ref': './test.json', 'x-scope': ['file:///c:/Users/anderegg/Documents/dev/OSPARC/jsonschematest/testapi.yaml']}}}}
is not valid under any of the given schemas

Failed validating 'oneOf' in schema['properties']['paths']['patternProperties']['^/']['properties']['get']['properties']['responses']['properties']['default']:
    {'oneOf': [{'$ref': '#/definitions/response'},
               {'$ref': '#/definitions/reference'}]}

On instance['paths']['/']['get']['responses']['default']:
    {'content': {'application/json': {'schema': {'$ref': './test.json',
                                                 'x-scope': ['file:///c:/Users/anderegg/Documents/dev/OSPARC/jsonschematest/testapi.yaml']}}},
     'description': 'some external json'}

my example openapi interface looks like this:

# test.yaml
openapi: "3.0.0"
info:
  description: This is a test api
  version: 1.0.0
  title: Test API

paths:
  /:
    get:
      tags: 
        - users
      summary: Returns a nice greeting
      description: Returns a nice greeting
      operationId: root_get
      responses:
        default:
          description: some external json
          content:
            application/json:
              schema:
                $ref: './test.json'

and my example json-schema:

// test.json
{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "title": "Test",
    "type": ["string", "null"],
    "format": "date-time"
}

Now I understand the problem comes from factories.py:SpecFactory:create where openapi_spec_validator is failing in validating my file because the ref does not follow #/something.

Am I wrong in thinking I can direclty reference a JSON schema?
If not, is it possible to disable the spec validation from client side? Or should I change something in the way I reference it?

Thanks for any input on this...