gtk2_live_wallpaper_from_reddit.rb

#!/usr/bin/env ruby
# OP
# Author : Emad Elsaid (https://github.com/blazeeboy)
# Added backup.
# Author : Oskar Truffer (https://github.com/otruffer) 
#
# autochanging wallpaper from reddit images
# you have to point the script to your existing
# file you set it as a wallpaper and it will override
# it with a new image every 5 minutes.
# 
# this script works on centos 6 with GNOME/GTK2 interface
require 'open-uri' # we'll need to download image with that
require 'ruby_reddit_api' # gem install ruby_reddit_api

# class will be initialized with
# a subreddit to monitor and a 
# destination file to write the
# downloaded image to it
class RedditWallpaper

  def initialize( subreddit, destination_file = 'img/bg.jpg', backup_folder = '' )
    @subreddit = subreddit
    @path = destination_file
    @downloaded = []
    @not_downloaded = []
    @backup_folder = backup_folder
  end

  # download the url to destination
  def download( url )
    image = open( "#{url}.jpg" ).read
    File.write  @path, image
  
    #if a backup folder is specified we save a backup of the wallpaper
    unless @backup_folder == ''
      backup image
    end
  end
  
  # add a copy of the image in the backup folder
  def backup( image )
    md5 = Digest::MD5.hexdigest(image)
    backup_file = File.join(@backup_folder, md5.to_s + '.jpg')

    File.open(backup_file, "w+") do |f|     
      f.write(image)   
    end
  end

  # update wallpaper and update images cache
  def update
    # make me a reddit client please
    r = Reddit::Api.new

    # update earth
    posts = r.browse @subreddit
    posts.each do |r|
      @not_downloaded << r.url if r.url.include?('imgur') and !@downloaded.include?(r.url)
    end

    image = @not_downloaded.shift
    download image
  end

end

# i'll get images from earthporn
# they have lots of great images of
# nature places
# and then i'll update it every 5 minutes
downloader = RedditWallpaper.new 'earthPorn', '/home/vagrant/ruby/wallpaperchanger/img/bg.jpg', '/home/vagrant/Pictures/Wallpapers'
loop do
  downloader.update
  sleep 5*60 # wait for 5 minutes
end