gistfile1.rb

require 'rubygems'
require 'hpricot'
require 'net/http'

class AlbumArt
  @api_key = "yourapikey"  

  # get_artwork_url_for_size :size => "small" (|| medium || large)
  # :artist => "Artist name", :album => "Album Name"
  def self.get_url(params)    
    sizes = {"small" => "SmallImage", "medium" => "MediumImage", "large" => "LargeImage"}
    
    asin = get_asin_for(params[:album], params[:artist])
  
    unless asin == nil
      url = build_url_for_lookup(asin)
      xml_data = Net::HTTP.get_response(URI.parse(url)).body
    
      doc = Hpricot.XML(xml_data)
    
      return doc.search("Item").at(sizes[params[:size]]).at("URL").innerHTML
    else
      return nil
    end
  end
  
  private
  def self.build_url_for_search(album, artist)
    # Remove any brackets, eg. (single version)
    album = album.gsub /\([^)]*\)/, ''
    
    keywords = CGI::escape("#{album}, #{artist}")
    url = "http://ecs.amazonaws.com/onca/xml?Service=AWSECommerceService&AWSAccessKeyId=#{@api_key}&Operation=ItemSearch&SearchIndex=Music&Keywords=#{keywords}&Count=1"
  end
  
  def self.build_url_for_lookup(asin)
    url = "http://ecs.amazonaws.com/onca/xml?Service=AWSECommerceService&AWSAccessKeyId=#{@api_key}&Operation=ItemLookup&ItemId=#{asin}&ResponseGroup=Images"
  end

  def self.get_asin_for(album, artist)
    url = build_url_for_search(album, artist)
  
    xml_data = Net::HTTP.get_response(URI.parse(url)).body
    
    if(xml_data != nil)
      doc = Hpricot.XML(xml_data)
      
      unless(doc.search("TotalResults").inner_html.to_i == 0)
        return doc.search("Item").at("ASIN").inner_html
      else
        return nil
      end
    else
      return nil
    end
  end
end