gistfile1.txt

require 'rss'
require 'open-uri'
 
p "Downloading rss index"
 
# If you are a Railscasts Pro subscriber, you will have a different RSS feed with Pro casts
# If this is the case, go to http://railscasts.com/, find it and sub it below
rss_string = open('http://feeds.feedburner.com/railscasts').read
rss = RSS::Parser.parse(rss_string, false)
videos_urls = rss.items.map { |it| it.enclosure.url }.reverse
 
videos_filenames = videos_urls.map {|url| url.split('/').last }
existing_filenames = Dir.glob('*.mp4')
missing_filenames = videos_filenames - existing_filenames
p "Downloading #{missing_filenames.size} missing videos"
 
missing_videos_urls = videos_urls.select { |video_url| missing_filenames.any? { |filename| video_url.match filename } }
 
missing_videos_urls.each do |video_url|
  filename = video_url.split('/').last
  next if File.exists? filename
  p "Downloading #{video_url}..."
  File.open(filename, "wb") do |saved_file|
    open(video_url, 'rb') do |read_file|
      saved_file.write(read_file.read)
    end
  end
  p "-> #Downloaded to #{filename}!"
end
p 'Finished synchronization'