API version format in Accept header

Hi,

The Versioning middleware specifies the syntax for the HTTP Accept header as follows:

module Grape
  module Middleware
    module Versioner
      # This middleware sets various version related rack environment variables
      # based on the HTTP Accept header with the pattern:
      # application/vnd.:vendor-:version+:format

In particular, "vnd.vendor-version" with a dash "-" between vendor and version. I've been trying to understand the origin of this syntax.

Is it possible to support dot "." version in addition to dash "-" version?

Such as:

vnd.vendor.version+format

Github, for example, uses this format. From https://developer.github.com/v3/:

Current Version

By default, all requests receive the v3 version of the API. We encourage you to explicitly request this version via the Accept header.

Accept: application/vnd.github.v3+json

A client that specifies the Accept header in this way, cannot be validated using the default versioning middleware in grape, with grape as the backend.

Thanks!

Start by locating the Grape::Middleware::Versioner implementation and the tests covering Accept-header version parsing. Trace how the existing vnd.vendor-version+format syntax is validated, then verify that vnd.vendor.version+format is accepted without breaking the dash form. Done means both formats are covered by tests and the GitHub-style header validates successfully.