Rotating backgrounds for OS X Lion

gistfile1.rb

#!/usr/bin/env ruby

require 'nokogiri' 
require 'open-uri'
require 'pathname'
require 'appscript'
require 'json'

include Appscript, MacTypes

@count_file = "/path/random_screenshot/count"

# All the top backgrounds
if File.exists?(@count_file) then
  open(@count_file, 'r') do |f|
    while line = f.gets
      @count = line.to_i + 1
    end
  end
else
  @count = 1
end

# Create a new file and write to it
open(@count_file, 'w') do |f|
  f.puts @count
end

@offset = 0
while (@offset + 20) < @count do
   @offset += 20
end

@count = @count - @offset

@url = "http://wallbase.cc/toplist/#{@offset}/213/gteq/1366x768/000/110/20/0"


doc = Nokogiri::HTML(open(@url))
href = doc.css(".thumb:nth-child(#{@count}) a.thdraggable").first.attributes['href']
doc = Nokogiri::HTML(open(href))
@src = doc.css('#bigwall img').first.attributes['src']

# Looks the same for both cases
filename = Pathname.new(@src).basename.to_s
new_photo = '/path/'+filename
photo = open(@src).read

open(new_photo, 'wb') do |file|
  file << photo
end

app('Finder').desktop_picture.set(FileURL.path(new_photo))