couch_listener.js

var sys = require('sys');
var http = require('http');

var host = '127.0.0.1';

var couch = http.createClient(5984, host);

var listen = function() {
  sys.log("listening");
  var request = couch.request('GET', '/demo/_changes?feed=continuous', {'host': host});
  request.end();
  request.addListener('response', function (response) {
    if (response.statusCode == 200) {
      response.setEncoding('utf8');
      response.addListener('data', function (chunk) {
	sys.log(chunk);
      });
      response.addListener('end', listen);
    } else {
      setTimeout(listen, 5000);
    }
  });
};

listen();

couch_listener.rb

require "eventmachine"
require "em-http"

class CouchListen
  def initialize database
    @database = database
    @feed_url = "http://127.0.0.1:5984/#{database}/_changes?feed=continuous"
  end

  def listen
    http = EventMachine::HttpRequest.new(@feed_url).get :timeout => 0
    http.stream  {|chunk| print(".") }
    http.errback { EM.add_timer(5) {listen} }
  end
end

EventMachine.run { CouchListen.new("memolane").listen }