class Grape::Middleware::Versioner::Path

def before
  path_info = Grape::Router.normalize_path(env[Rack::PATH_INFO])
  return if path_info == '/'
  [mount_path, Grape::Router.normalize_path(prefix)].each do |path|
    path_info.delete_prefix!(path) if path.present? && path != '/' && path_info.start_with?(path)
  end
  slash_position = path_info.index('/', 1) # omit the first one
  return unless slash_position
  potential_version = path_info[1..slash_position - 1]
  return unless potential_version.match?(pattern)
  version_not_found! unless potential_version_match?(potential_version)
  env[Grape::Env::API_VERSION] = potential_version
end