itunes_feed.rb

require 'feedzirra'

module ItunesFeed
  module Music

    DEFAULT_FEED_TYPE = 'topalbums'

    def music
      @feed_type = ItunesFeed::Music::DEFAULT_FEED_TYPE
      self
    end

    def top_albums
      @feed_type = 'topalbums'
      self
    end

    def top_songs
      @feed_type = 'topsongs'
      self
    end

  end

  class Client

    DEFAULT_LIMIT = 10
    DEFAULT_EXPLICIT = true

    include ItunesFeed::Music

    def initialize(options={})
      @country    = options[:country]
      @limit      = options[:limit] || DEFAULT_LIMIT
      @explicit   = options[:explicit] || DEFAULT_EXPLICIT
      @feed_type  = options[:feed_type]
    end

    def country(c)
      @country = c
      self
    end

    def limit(l=DEFAULT_LIMIT)
      @limit = l
      self
    end

    def explicit(e=DEFAULT_EXPLICIT)
      @explicit = e
      self
    end

    def feed_type(ft)
      @feed_type = ft
      self
    end

    def genre(g)
      @genre = g
      self
    end


    def fetch
      Feedzirra::Feed.fetch_and_parse(feed_url)
    end

    private

    def feed_url
      url = 'http://itunes.apple.com/'
      url << @country
      url << '/rss/'
      url << "#{@feed_type}/"
      url << "limit=#{@limit}/"
      url << "genre=#{@genre}/" if @genre
      url << "explicit=true/" if @explicit
      url << "xml"
    end
  end
end

feed = ItunesFeed::Client.new.country('us').music.fetch
puts feed.inspect