def accept_uri_http
    OptionParser.accept URI::HTTP do |value|
      begin
        uri = URI.parse value
      rescue URI::InvalidURIError
        raise OptionParser::InvalidArgument, value
      end

      unless ['http', 'https', 'file'].include?(uri.scheme)
         raise OptionParser::InvalidArgument, value
      end

      value
    end
  end
#
Allows OptionParser to handle HTTP URIs.