Battlefield 2 RCon module

bf2rcon.js

var net = require('net');
var crypto = require('crypto');
var util = require('util');
var events = require('events');
function rcon(options) {
  $rcon = this;
	this.client = net.connect(
		{
			host: options.host,
			port: options.port
		}, function() {
			console.log("Connected!");
		}
	);
	this.client.on('data', function(data) {
		var sent = data.toString();
		if(sent.indexOf('### Digest seed: ') != -1) {
			var seed = sent.replace("### Digest seed: ", "").trim();
			console.log("seed: " + seed);
			$rcon.client.write("login " + crypto.createHash('md5').update(seed + options.password).digest('hex') + "\n");
		}
		if(sent.indexOf('Authentication successful') != -1) {
			$rcon.emit('authed');
		}
	});
}
util.inherits(rcon, events.EventEmitter);
rcon.prototype.send = function(data, callback) {
	this.client.write(data + "\n");
	this.client.once("data", function(data) {
		callback(data);
	});
}
exports.rcon = rcon;

listplayers.js

var bf2 = require('./bf2rcon');
var options = {
  host: "127.0.0.1",
	port: 12345,
	password: "*password*"
}
var rcon = new bf2.rcon(options);
var usermatch = /Id: \s?([0-9]*) - (.*) is remote ip: ([0-9\.]*):([0-9]*)/g;
var userlist = [];
rcon.on("authed", function() {
	userlist = [];
	this.send("exec admin.listPlayers", function(data) {
		data = data.toString();
		match = usermatch.exec(data);
		while(match != null) {
			userlist.push({
				id: match[1],
				name: match[2],
				ip: match[3],
				port: match[4]
			});
			match = usermatch.exec(data);
		}
		console.log(userlist);
	});
});

Nice RCON script. Is there a way to change this script so the RCOn port ( connection ) stays open and the userlist will be retrieved every second?