mixin.rb

    module Request
      HEADERS = { 'Content-Type' => 'application/json' }.freeze
      
      def self.add_headers(headers)
        HEADERS.merge!(headers)
      end

      def get_request(path)
        uri = URI.parse(path)
        http = Net::HTTP.new(uri.host, uri.port)
        request = Net::HTTP::Get.new(uri.request_uri, HEADERS)
        response = http.request(request)
      end
    end

class Client
  include Request
  
  def initialize()
    Request.add_headers("X-Custom" => "foo")
  end
end