Basic but well working way to find favicons by domain in Ruby

favicon_finder.rb

class FaviconFinder
  require 'open-uri'
  attr_accessor :favicon_url

  def initialize domain = "example.com"
    @favicon_url = nil

    ["/favicon.ico", "/favicon.png"].each do |file|
      url = "http://#{domain}#{file}"
      uri = URI(url)
      request = Net::HTTP.new uri.host
      response= request.request_head uri.path
      if response.code.to_i == 301
        url = response.header['location']
        uri = URI(url)
        request = Net::HTTP.new uri.host
        response= request.request_head uri.path
      end
      @favicon_url = url if response.code.to_i == 200
    end

    if @favicon_url.nil?
      index = open("http://#{domain}")
      data = Nokogiri::HTML(index.read)
      @favicon_url = data.css('link[rel="shortcut icon"]').first
      @favicon_url = data.css('link[rel="icon"]').first if @favicon_url.nil?
      if !@favicon_url.nil? && !@favicon_url['href'].include?(index.base_uri.to_s)
        @favicon_url = "#{index.base_uri.to_s}#{@favicon_url['href']}"
      end
    end
  end
end

usage.rb

FaviconFinder.new("facebook.com").favicon_url
FaviconFinder.new("google.com").favicon_url