railscast video download script from ery/railscasts-downloader

railscasts_downloader.rb

require 'rss'

if File.exist?("rss.index")
  p 'Read rss index'
  rss_string = ''
  File.open('rss.index', 'r') do |file|
    while line = file.gets
      rss_string += line
    end
  end
else
  p 'Downloading rss index'
  rss_string = open('http://feeds.feedburner.com/railscasts').read
  File.open('rss.index', 'w') {|file| file.puts rss_string }
end

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
  p filename
  p %x(wget -c #{video_url} -O #{filename}.tmp )
  p %x(mv #{filename}.tmp #{filename} )
end
p 'Finished synchronization'