Zally reports violation of rule #110 for endpoints returning binary data

I have endpoint which returns file content as binary

  "/reports/{report-id}":
    get:
      produces:
        - application/pdf
      responses:
        '200':
          description: Return report as a PDF file
          schema:
            type: file

Zally reports violation:

MUST – Response As JSON Object
Always Return JSON Objects As Top-Level Data Structures To Support Extensibility
Rule: https://zalando.github.io/restful-api-guidelines/#110

But in fact this is totally valid according to rule 168

[tkrop]

A media type is defined to have the following form:

top-level type name / subtype name [ ; parameters ]
top-level type name / [ tree. ] subtype name [ +suffix ] [ ; parameters ]

As a consequence the actual regex must look like:

^[^/]+/(json|[^+;]+\+json)(;.*)?$

[mkulak]

I propose to reverse this logic. Since we assume that JSON is default data type I think it makes sense to check for it by default. And skip this check only for those endpoints that both have content type specified and value of this content type doesn’t contain substring “json”. What do you think? @netme @tkrop @maxim-tschumak