Headers & Non-2XX status Codes

[dbushong]

Some REST APIs like to respond with non-2XX status codes, and sometimes they have important details you need in the response headers (two separate issues, but related when you get 30X + Location header, e.g.)

Proposal:

1. For all properties in the responses object in a swagger operation entry, set min/maxStatusCode properties in the fetch to support them; this is gofer-specific behavior, and overly broad, but should be an adequate workaround for now
2. For all responses that have defined response headers, make the headers, conforming to their defined schemae, available in one enclosing response dictionary-style object, keyed by the lowercase header names, under...some unique version of the word "headers"(?)

e.g.:

paths:
  '/go/{id}':
    get:
      responses:
        301:
          description: redirect to page for id
          headers:
            Location:
              type: string
              format: uri

and then in your GraphQL query you should be able to ask for { headers { location } } - the only question is how to choose the name headers so it doesn't conflict with something in the body schema, potentially.