server/www/session.js

function Session(modules) {
  var key = null;
  var name = null;
  var loggedIn = false;

  modules.messaging.addEventListener(["Welcome"], function(o) {
    key = o.key;
    modules.save.set('player.id', key);
  });

  modules.messaging.addEventListener(["Relay", "LogIn"], function(o) {
    if(is(o.from)) {
      name = o.message.name;
    }
  });

  return {
    is: is,
    getKey: getKey,
    loggedIn: loggedIn,
    start: start
  };

  function is(sessionKey) {
    return key == sessionKey;
  }

  function getKey() {
    return key;
  }

  function isLoggedIn() {
    return loggedIn;
  }

  function start(name) {
    var myID = modules.save.get('player.id');
    if(myID != undefined) {
      modules.messaging.send({tag: 'Tadaima', myID: myID, name: name});
    } else {
      modules.messaging.send({tag: 'Hello', name: name});
    }
    modules.save.set('player.name', name);
  }
}