Download all Railscasts episodes

download_railscasts.rb

require 'httparty'
require 'nokogiri'
require 'json'
require 'pry'

class Downloader
  def initialize(episode)
    system("wget #{episode.direct_link}")
  end
end

class Episode
  include HTTParty
  base_uri 'http://railscasts.com/episodes/'

  attr_reader :revised
  attr_reader :slug
  attr_reader :metadata

  def self.find(episode_number)
    full_url = self.get("http://railscasts.com/episodes/#{episode_number}").request.last_uri.to_s
    slug = full_url.scan(/episodes\/(.*)/).last.last

    Episode.new(slug)
  end

  def initialize(episode_slug)
    @slug = episode_slug
    episode_as_json = JSON.parse(HTTParty.get("http://railscasts.com/episodes/#{@slug}.json").body)
    @metadata = episode_as_json
    self
  end

  def has_revised?
    metadata["revised"]
  end

  def is_pro?
    metadata["pro"]
  end

  def revised
    return nil unless has_revised?

    episode_page = Nokogiri::HTML(self.class.get(slug).body)
    link = episode_page.xpath("//strong/a").first
    revised_slug = link.attributes['href'].value

    Episode.find(revised_slug)
  end

  def download
    Downloader.new(self)
  end

  def direct_link
    doc = ::Nokogiri::HTML(self.class.get("http://railscasts.com/episodes/#{slug}").body)
    doc.xpath("//ul[@class='downloads horizontal']/li/a").each do |link|
      value = link.attributes['href'].value
      return value if value.include? 'mp4'
    end
  end
end

(1..417).each do |episode_number|
  begin
    episode = Episode.find(episode_number)

    puts "Getting episode #{episode_number}"

    episode.download

    if episode.has_revised?
      revised = episode.revised
      puts "Getting revised episode"
      revised.download unless revised.is_pro?
    end

  rescue
    next
  end
end