ars_live.rb

# Pipe Ars Technica's live Apple event coverage into a Campfire room.
# http://arstechnica.com/apple/news/2010/01/tablet-live-event-liveblog.ars 
#
# Usage:
#   $ gem install -r hpricot tinder
#   $ ruby -rubygems ars_live.rb -ssl mysubdomain myroomid myapikey

require "hpricot"
require "open-uri"
require "tinder"
require "time"

module ArsLive
  class Feed
    FEED_URL = "http://rss.coveritlive.com/rss.php?altcast_code=%s"

    def initialize(id)
      @url = FEED_URL % id
      @items = []
    end

    def new_items
      document = Hpricot(open(@url).read)
      modified = Time.parse(document.search("channel > lastBuildDate").inner_text)

      if @modified != modified
        @modified = modified
        new_items = items_from(document.search("item")) - @items
        @items += new_items
        new_items
      else
        []
      end
    end

    def items_from(elements)
      elements.map { |element| Item.new(element) }.sort_by { |item| item.date }.reverse
    end
  end

  class Item
    attr_reader :date

    def initialize(element)
      @date = Time.parse(element.search("pubdate").inner_text)
      @enclosure = element.search("enclosure")
      @description = Hpricot(element.search("description").inner_text)
    end

    def has_enclosure?
      @enclosure.any?
    end

    def image
      @enclosure.attr("url")
    end

    def text
      cells = @description.search("td")
      cells.last.inner_text.strip if cells.any?
    end

    def body
      @body ||= has_enclosure? ? image : text
    end

    def hash
      @hash ||= [date, body].join.hash
    end

    def eql?(other)
      hash == other.hash
    end
  end
end

if __FILE__ == $0
  ssl = ARGV.first == "-ssl" && ARGV.shift
  if ARGV.length < 3
    $stderr.puts "usage: #$0 [-ssl] subdomain roomid apikey"
    exit 1
  end

  subdomain, room_id, api_key = ARGV[0, 3]
  campfire = Tinder::Campfire.new(subdomain, :ssl => ssl)
  campfire.login(api_key, nil)
  room = Tinder::Room.new(campfire, "id" => room_id)

  feed = ArsLive::Feed.new("b0eff04045")
  feed.new_items  # don't print existing items, in case you have to restart the script

  loop do
    sleep 3
    begin
      feed.new_items.first(10).each do |item|
        room.speak(item.body)
      end
    rescue Errno::ETIMEDOUT, Timeout::Error
    end
  end
end