tube.rb

require 'net/http'
require 'cgi'
require 'rubygems'
require 'xmlsimple'

class TubeUpdates
  API_URL = 'http://api.tubeupdates.com/?method=%s&lines=%s&format=%s'

  def initialize(stations, options = {})
    @stations = stations
    @options = { :format => :xml, :method => 'get.status' }
  end

  def stations
    CGI.escape @stations.join(',')
  end

  def url
    sprintf API_URL, @options[:method], stations, @options[:format]
  end

  def get_updates
    get_and_parse_api_data
  end

  def get_api_data
    data = Net::HTTP.get_response(URI.parse(url)).body
    XmlSimple.xml_in(data, { 'ForceArray' => false, 'GroupTags' => { 'lines' => 'line', 'messages' => 'message' } })
  end

  def parse(data)
    lines = {}
    data['lines'].each do |line|
      lines[line['name']] = line
    end
    lines
  end

  def get_and_parse_api_data
    parse get_api_data
  end
end

tube = TubeUpdates.new(%w(central hammersmithcity victoria))
tube.get_updates.each do |name, values|
  puts "#{name}: #{values['status']}"
end