parse

# File actionpack/lib/action_dispatch/http/mime_type.rb, line 197
      def parse(accept_header)
        if !accept_header.include?(',')
          accept_header = accept_header.split(PARAMETER_SEPARATOR_REGEXP).first
          parse_trailing_star(accept_header) || [Mime::Type.lookup(accept_header)].compact
        else
          list, index = [], 0
          accept_header.split(',').each do |header|
            params, q = header.split(PARAMETER_SEPARATOR_REGEXP)

            next unless params
            params.strip!
            next if params.empty?

            params = parse_trailing_star(params) || [params]

            params.each do |m|
              list << AcceptItem.new(index, m.to_s, q)
              index += 1
            end
          end
          AcceptList.sort! list
        end
      end