MWSのサンプルコードをオブジェクト指向っぽくしてみた。

mws.rb

# -*- encoding: utf-8 -*-
# Original code is http://aws.typepad.com/jp_mws/2012/12/amazon-mws-ruby-sample.html

require 'uri'
require 'time'
require 'openssl'
require 'base64'
require "net/https"
require "pp"
require 'active_support'
require 'active_support/core_ext'

module MWS
  class Base
    METHOD="GET"
    ENDPOINT_SCHEME = 'https://'
    ENDPOINT_URI    = '/Products/2011-10-01'
  
    def initialize(config)
      @c = self.class
      @params = {
        "AWSAccessKeyId"  => config[:access_key_id],
        "MarketplaceId"   => @c::MARKET_PLACE_ID,
        "SellerId"        => config[:seller_id],
        "SignatureMethod" => "HmacSHA256",
        "SignatureVersion"=> "2",
        "Version"         => "2011-10-01",
      }
      @private_key = config[:private_key]
    end
  
    def ListMatchingProducts(query, query_context_text_id)
      params = {
        "Action" => "ListMatchingProducts",
        "Query"  => query,
        "QueryContextId" => query_context_text_id,
      }
      self.request(params)
    end
  
    def request(params)
      params["Timestamp"] = Time.now.utc.iso8601
      req_params = @params.merge(params)
  
      #Sorting parameters - パラメータのソート
      values = req_params.keys.sort.collect {|key|  [url_encode(key), url_encode(req_params[key].to_s)].join("=") }
      param=values.join("&")
  
      #Creating Signature String - 電子署名の作成
      signtemp = METHOD+"\n"+@c::ENDPOINT_HOST+"\n"+ENDPOINT_URI+"\n"+param
      signature_raw = Base64.encode64(OpenSSL::HMAC.digest('sha256',@private_key,signtemp)).delete("\n")
      signature=URI.escape(signature_raw,Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))
  
      param+="&Signature="+signature
      #Creating URL - URLの作成
      url=ENDPOINT_SCHEME+@c::ENDPOINT_HOST+ENDPOINT_URI+"?"+param
      puts url
  
  
      uri=URI.parse(url)
  
      http = Net::HTTP.new(uri.host, uri.port)
      http.use_ssl = true
      http.verify_mode = OpenSSL::SSL::VERIFY_NONE
  
      #performing HTTP access - HTTPアクセスを実行
      request = Net::HTTP::Get.new(uri.request_uri)
      response = http.request(request)
  
      #output results - 結果を出力
      Hash.from_xml(response.body)
    end
  
    def url_encode(string)
      return URI.escape(string,Regexp.new("[^#{URI::PATTERN::UNRESERVED}]"))
    end
  end

  class US < Base
    ENDPOINT_HOST   = 'mws.amazonservices.com' #Endpoint to US MWS
    MARKET_PLACE_ID = 'ATVPDKIKX0DER';         #Markeplace is US
  end

  class JP < Base
    ENDPOINT_HOST   ='mws.amazonservices.jp' #Endpoint to JP MWS
    MARKET_PLACE_ID ='A1VC38T7YXB528';       #Markeplace is JP
  end
end

if $0 == __FILE__
  #####################CONFIG-各種設定項目#####################
  ACCESS_KEY_ID='************'
  PRIVATE_KEY='************'
  SELLER_ID='************'
  #####################CONFIG END##################

  #####################INPUT-入力項目#######################
  QUERY="red october"
  QUERYCONTEXTID="Books"
  #####################INPUT END###################
  config = {
    :access_key_id   => ACCESS_KEY_ID,
    :private_key     => PRIVATE_KEY,
    :seller_id       => SELLER_ID,
  }

  mws = MWS::US.new(config)
  puts mws.ListMatchingProducts(QUERY,QUERYCONTEXTID)
end