get_items_via_rakuten_webservice.rb

require 'rubygems'
require 'net/http'
require 'json'
require 'uri'

$KCODE='UTF-8'

dev_id = "YOUR DEVELOPER ID"
aff_id = "YOUR AFFILIATE ID"

request_address = "http://api.rakuten.co.jp/rws/3.0/json?" + 
  "developerId=#{dev_id}" + 
  "&affiliateId=#{aff_id}"+
  "&operation=ItemSearch" + 
  "&version=2009-04-15" + 
  "&keyword=#{URI.encode("keyword")}" +
  "&sort=#{URI.encode('+updateTimestamp', /[\-\+]/)}" 

request_uri = URI.parse(request_address)
response = Net::HTTP.get(request_uri.host, request_uri.path + "?" + request_uri.query, request_uri.port)

items = JSON.parse(response)['Body']['ItemSearch']['Items']['Item']
items.each do |item|
  puts <<-DETAIL
    商品名：#{item['itemName']}(#{item['itemCode']})
    商品価格：#{item['itemPrice']}
    URL：#{item['affiliateUrl']}
  DETAIL
end