Simple Amazon Product Advertisement api client, using Vacuum and Nokogiri. https://github.com/hakanensari/vacuum

amazon_item.rb

class AmazonItem
  attr_accessor :asin, :url, :manufacturer, :category, :title, \
                :ean, :item_number, :model, :lowest_price, :image_url, \
                :list_price, :offer_price

  def initialize(attributes = {})
    update_attributes(attributes)
  end

  def update_attributes(new_attributes)
    return update_attributes_from_xml(new_attributes) if new_attributes.respond_to?(:css)

    new_attributes.each do |key, value|
     if self.respond_to?("#{key}=".to_sym) then
       self.send("#{key}=".to_sym, value) unless value.nil?
     else
       raise ArgumentError, "unkown :#{key} attribute"
     end
    end
    self
  end

  def update_attributes_from_xml(item)
    return self unless item
    update_attributes(
      ean: item.css('ItemAttributes EAN').first.try(:text),
      item_number: item.css('ItemAttributes ItemPartNumber').first.try(:text),
      model: item.css('ItemAttributes Model').first.try(:text),
      lowest_price: get_price(item.css('LowestNewPrice Amount').first),
      list_price: get_price(item.css('ListPrice Amount').first),
      offer_price: get_price(item.css('Offer Price Amount').first),
      image_url: item.css('LargeImage URL').first.try(:text),
      asin: item.css('ASIN').first.text,
      url: item.css('DetailPageURL').first.text,
      manufacturer: item.css('ItemAttributes Manufacturer').first.text,
      category: item.css('ItemAttributes ProductGroup').first.text,
      title: item.css('ItemAttributes Title').first.text,
    )
  end

  def lookup
    return unless asin or ean
    req = self.class.get_vacuum
    to_request = %w{AlternateVersions Images ItemAttributes Similarities Offers}
    res = req.get query: {  'Operation'   => 'ItemLookup',
                            'ResponseGroup' => to_request.join(','),
                            'IdType' => asin ? 'ASIN' : 'EAN',
                            'ItemId' => asin || ean,
                            'SearchIndex' => asin ? '' : 'All' }
    lookup_doc = Nokogiri::XML(res.body)
    return unless lookup_doc
    update_attributes_from_xml lookup_doc.css('Item').first
  end

  class << self
    def search(search_query)
      req = get_vacuum
      search_query = search_query.join(' ') if search_query.is_a?(Array)
      res = req.get query: {  'Operation' => 'ItemSearch',
                              'SearchIndex' => 'All',
                              'Keywords'    => search_query }
      search_doc = Nokogiri::XML(res.body)
      items = search_doc.css('Item')
      items.map{ |item| new(item) }
    end

    def get_vacuum
      Thread.current[:amazon_vacuum] = begin
        vacuum = Vacuum.new('DE')
        vacuum.configure key: ENV['AMAZON_ACCESS_KEY'],
                         secret: ENV['AMAZON_SECRET'],
                         tag: ENV['AMAZON_TAG']
        vacuum
      end
    end
  end

  private
    def get_price(doc)
      return unless doc
      doc.text.to_f / 100
    end
end