How can I use a hyperschema that references external schemas?

Hello, I started this question as a comment at brandur/json_schema#22, but it's perhaps more appropriate here.

I'd like to break my API hyperschema into a separate files for better modularity and easier management; and in fact I may want to refer to schemas that are defined externally, but I'm not certain how to do that with Committee:Middleware::RequestValidation.

For example, the hyperschema might include something like:

"links": [
    {
      "description": "Create a widget",
      "href": "/widgets",
      "method": "POST",
      "rel": "create",
      "title": "Create Widget",
      "schema": { "$ref": "file://schemas/widget-create-request.schema.json" },
      "targetSchema": { "$ref": "file://schemas/widget-create-response.schema.json" }
    },
    ...
  ]

The request and response schemas might themselves refer to a URI for an externally-defined widget schema, e.g. something like:

{
    "type": "object",
    "properties": {
         "metadata": { "type": "object" }
         "widget": { "$ref": "http://widget-host.com/schemas/widget.schema.json" }
    },
    "required": ["widget"]
}

In the discussion at brandur/json_schema#22 it seems that one must set things up to use "id" rather than $ref, and must pre-load the external schemas into a JsonSchema::DocumentStore which is then used to expand references on a JsonSchema object.

I can probably figure out the use of "id" in my schemas, but how can I use JsonSchema::DocumentStore when configuring the middleware -- there's no documented parameter for it at:

 use Committee::Middleware::RequestValidation, schema: JSON.parse(File.read(...))

Thanks for any advice!

PS. Lacking anything else, I'll probably do a preprocessing step on my own to load the schema and recursively expand $ref's, before passing it to use Committee::Middleware::RequestValidation. Not the most elegant thing in the world, but should work.

Start with Committee::Middleware::RequestValidation and the documented schema configuration, then trace how JsonSchema::DocumentStore is expected to relate to external references. No file or test is named; done would be documentation that explains whether and how external schemas can be configured, including the role of id and $ref.