amazon-ecs usage for https://attonblog.blogspot.com/2017/12/okinawa-rb-advent-calendar-2017.html

fix_request.rb

result = Amazon::Ecs.send_request({response_group: 'Images,ItemAttributes,Large',
                          operation: 'ItemSearch',
                          browse_node: '2293143051',
                          minimum_price: 0,
                          maximum_price: 0,
                          search_index: 'Books'
                          marketplace: 'jp'})
# return items

kobo.rb

API_END_POINT  = 'https://app.rakuten.co.jp/services/api/Kobo/EbookSearch/20170426'
APPLICATION_ID = 'hoge'
AFFILIATE_ID   = 'fuga'

ElementInformations = ['largeImageUrl', 'title', 'affiliateUrl', 'itemPrice', 'publisherName']

DefaultOpts    = {affiliateId: AFFILIATE_ID,
                  applicationId: APPLICATION_ID,
                  elements: ElementInformations.join(','),
                  formatVersion: 2,
                  field: 0,
                  hits: 30,
                  koboGenreId: 101,
                  language: 'JA',
                  salesType: 0,
                  sort: '+itemPrice'}

def post hash
  uri           = URI.parse(API_END_POINT)
  https         = Net::HTTP.new(uri.host, 443)
  https.use_ssl = true
  path          = uri.path
  path         += '?'
  path         += URI.encode_www_form(DefaultOpts.merge(hash))

  request       = Net::HTTP::Post.new(path)
  https.request(request)
end
post(1) # request 1 page

request.rb

require 'amazon/ecs'
Amazon::Ecs.configure do |options|
  options[:subscription_id] = options[:AWS_access_key_id] = 'hoge'
  options[:AWS_secret_key]    = 'fuga'
  options[:associate_tag]     = 'piyo'
end
result = Amazon::Ecs.send_request({response_group: 'Images,ItemAttributes,Large',
                          operation: 'ItemSearch',
                          browse_node: '2293143051',
                          minimum_price: 0,
                          maximum_price: 0,
                          search_index: 'Books'})