das_download.rb

#! /usr/bin/env ruby
# usage:
# $ das_download.rb

require "mechanize"
require "fileutils"

class DasDownloader
  attr_reader :agent, :email, :password

  def initialize
    @agent = Mechanize.new
  end

  def screencasts
    screencasts = []
    screencasts_metadata_html.each do |html|
      next unless (meta = html.at("h1.season_title"))

      season = meta.at("img").attr("alt")

      html.search(".episode").each do |episode|
        title = episode.at(".title").text.gsub("/", "-")
        url = episode.at("a").attr("href")
        download_url = url + "/download"
        description = episode.at(".subtitle").text
        duration = episode.at(".duration").text

        screencasts << Screencast.new(season, title, description, duration, download_url)
      end
    end

    screencasts
  end

  def run
    screencasts.each do |screencast|
      download screencast
    end
  end

  private

  def download(screencast)
    puts "Downloading #{screencast.season} - #{screencast.title}"

    FileUtils::mkdir_p(screencast.season)
    Dir.chdir(screencast.season) do
      FileUtils::mkdir_p(screencast.title)
      Dir.chdir(screencast.title) do
        File.open("metadata.txt", "w") do |metadata|
          metadata.puts "Title: #{screencast.title}"
          metadata.puts "Description: #{screencast.description}"
          metadata.puts "Duration: #{screencast.duration}"
        end
        
        agent.get("https://destroyallsoftware.com#{screencast.url}").save("screencast.mov")
      end
    end
  end

  def screencasts_metadata_html
    agent.get "https://www.destroyallsoftware.com/screencasts/catalog"
    agent.page.search(".season").reverse
  end

  Screencast = Struct.new(:season, :title, :description, :duration, :url)
end

DasDownloader.new.run