AtomStream.rb

require 'rubygems'
require 'eventmachine'
require 'open-uri'
require 'libxml'



class XmlHandler
  include LibXML::XML::SaxParser::Callbacks

  def initialize()
    @parser = LibXML::XML::SaxParser.new(LibXML::XML::Parser::Context.new)
    @parser.callbacks = self
  end

  def parse(data)
    puts data
    LibXML::XML::SaxParser.string(data)
    @parser.parse
  end

  def on_error(error)
    puts "#{error}"
  end

  def on_start_element(element, attributes = {})
  end

  def on_end_element(element)
  end

  def on_characters(text)
  end

  def method_missing(method_name, *attributes, &block)
    puts method_name + " missing"
  end

end


class AtomStreamHandler < EventMachine::Connection
  def initialize(params)
    @uri = params[:uri]
    @callback = params[:callback]
    @elem = nil
    @xml_handler = XmlHandler.new()
    @started = false
    super
  end

  def post_init
    send_data("GET #{@uri.request_uri} HTTP/1.0\r\n" +
    "Host: #{@uri.host}\r\n" +
    "\r\n")
  end

  def receive_data(data)
    data.each_line do |line|
      @xml_handler.parse(line) if @started
      @started = true if line =~ /\A\r\n/
    end
  end
end


EventMachine::run do
  @uri = URI::parse("http://updates.sixapart.com/atom-stream.xml")
  EventMachine::connect @uri.host, @uri.port, AtomStreamHandler, {:uri => @uri}
end