download_railscasts.rb

#!/usr/bin/env ruby

require 'rss'

subscriber_id = "41TjtXC14dnMq0aFyllyKw"
download_dir = "/srv/http/data.ineu.pp.ua/shared/public/system/railscasts"

url = "http://railscasts.com/subscriptions/#{subscriber_id}/episodes.rss"
feed = RSS::Parser.parse(url)

# only pro/revised episodes
urls = feed.items.map { |i| i.enclosure.url }.select {|url| url =~ /subscriptions/ }

Dir.chdir download_dir
local_ids = Dir['*'].map { |i| i.split('-').first }
remote_ids = urls.map { |url| File.basename url }.map { |i| i.split('-').first }

diff = remote_ids - local_ids

diff.each do |id|
  url = urls.detect { |url| url.include? id }
  `wget #{url}`
end