bijin_wallpaper.rb

#!/usr/bin/env ruby
# * * * * * bijin_wallpaper.rb

require 'pathname'
require 'open-uri'
require 'fileutils'

include FileUtils

IMAGE_DIR = '/Users/youpy/Documents/bijint'

def main
  now = Time.now
  image_path = image_path(now)

  mkdir_p image_path.dirname

  unless image_path.exist?
    File.open(image_path, "w") do |f|
      open(image_url(now)) do |img|
        f.write img.read
      end
    end
  end

  set_desktop_picture(image_path)
end

def image_path(now)
  Pathname.new(IMAGE_DIR) + '%s.jpg' % now.strftime('%H%M')
end

def image_url(now)
  'http://www.bijint.com/jp/img/photo/%s.jpg' % now.strftime('%H%M')
end

def set_desktop_picture(path)
  IO.popen("osascript", "r+") do |io|
    io.puts <<END
tell application "Finder"
  set pFile to POSIX file "#{path}" as string
  set current to desktop picture as string
	if current is not pFile then
		set desktop picture to file pFile
	end if
end tell
END
  end
end

main