huttj · December 26, 2014 04:25
diff --git a/index.html b/index.html
 <!doctype html>
 <html>
    <head>
        <title>Heartbeat test.</title>
        <script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
    </head>
    <body>
        <script>
            // Let the user set the ID in the query variable
            var id = parseInt((window.location.search.match(/id=(\d{2})/) || []) [1]);

            // If the user did  not set the ID, choose one at random and set it
            // as the query variable (for easy copy-and-paste)
            if (!id) {
                id = Math.round(Math.random()*100), 10
                window.location.search = "?id=" + id;
            }

            // Show the current client ID
            $('body').append($('<h1></h1>').text('Your ID: ' id));

            // Show a  list of the connected clients
            var clients = $('<p class="clients"></p>');
            $('body').append(clients);

            // Poll the server with a heartbeat request every second.
            var heartbeat = setInterval(function() {

                $.get('http://localhost:9001/heartbeat?id=' + id, function(data) {
                    var d = JSON.parse(data);
                    clients.text(d.join(', ') + ' (' + d.length + ' clients)');
                    console.log(data);
                });

            }, 1000);


        </script>
    </body>
 </html>
diff --git a/index.js b/index.js
 var http = require('http');
 var fs = require('fs');

 // Simple client page that sends a "heartbeat" GET request every second
 var index = fs.readFileSync('index.html');

 // List of clients' setTimeout IDs keyed on client-provided 'ID'
 // Represents 'active' clients
 var clients = {};

 // Single request
 http.createServer(function(req, res) {
    console.log(req.url);

    // If the word 'heartbeat' is present, get the ID associated with the
    // request and reset its self-removal timeout--that is, give it another
    // Five seconds to check back in before removing it from the list
    if (req.url.match(/heartbeat/)) {

        // Get the ID from the request header
        var id = req.url.match(/id=(\d+)/)[1];

        // Remove the timeout that would remove the ID from the clients list
        clearTimeout(clients[id]);

        // Set a new timeout to remove the client if they haven't checked in
        // within five seconds from now
        clients[id] = setTimeout((function(_id) {
            // Capture the ID in a local variable so it's accessible in this scope
            return function() {
                console.log('deleting', _id);
                delete clients[_id];
            }
        }(id)), 5000);

        // Send out a list of the connected clients the the client
        var clientList = [];
        for (var prop in clients) {
            clientList.push(prop);
        }
        res.end(JSON.stringify(clientList));
    } else {

        // If 'heartbeat' is not in the url, send a copy of the index file.
        res.writeHead(200, {'Content-Type': 'text/html'});
        res.end(index);
    }
 }).listen(9001);

 console.log('Listening on port ' + 9001);
	<!doctype html>
	<html>
	<head>
	<title>Heartbeat test.</title>
	<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
	</head>
	<body>
	<script>
	// Let the user set the ID in the query variable
	var id = parseInt((window.location.search.match(/id=(\d{2})/) \|\| []) [1]);

	// If the user did not set the ID, choose one at random and set it
	// as the query variable (for easy copy-and-paste)
	if (!id) {
	id = Math.round(Math.random()*100), 10
	window.location.search = "?id=" + id;
	}

	// Show the current client ID
	$('body').append($('<h1></h1>').text('Your ID: ' id));

	// Show a list of the connected clients
	var clients = $('<p class="clients"></p>');
	$('body').append(clients);

	// Poll the server with a heartbeat request every second.
	var heartbeat = setInterval(function() {

	$.get('http://localhost:9001/heartbeat?id=' + id, function(data) {
	var d = JSON.parse(data);
	clients.text(d.join(', ') + ' (' + d.length + ' clients)');
	console.log(data);
	});

	}, 1000);


	</script>
	</body>
	</html>
	var http = require('http');
	var fs = require('fs');

	// Simple client page that sends a "heartbeat" GET request every second
	var index = fs.readFileSync('index.html');

	// List of clients' setTimeout IDs keyed on client-provided 'ID'
	// Represents 'active' clients
	var clients = {};

	// Single request
	http.createServer(function(req, res) {
	console.log(req.url);

	// If the word 'heartbeat' is present, get the ID associated with the
	// request and reset its self-removal timeout--that is, give it another
	// Five seconds to check back in before removing it from the list
	if (req.url.match(/heartbeat/)) {

	// Get the ID from the request header
	var id = req.url.match(/id=(\d+)/)[1];

	// Remove the timeout that would remove the ID from the clients list
	clearTimeout(clients[id]);

	// Set a new timeout to remove the client if they haven't checked in
	// within five seconds from now
	clients[id] = setTimeout((function(_id) {
	// Capture the ID in a local variable so it's accessible in this scope
	return function() {
	console.log('deleting', _id);
	delete clients[_id];
	}
	}(id)), 5000);

	// Send out a list of the connected clients the the client
	var clientList = [];
	for (var prop in clients) {
	clientList.push(prop);
	}
	res.end(JSON.stringify(clientList));
	} else {

	// If 'heartbeat' is not in the url, send a copy of the index file.
	res.writeHead(200, {'Content-Type': 'text/html'});
	res.end(index);
	}
	}).listen(9001);

	console.log('Listening on port ' + 9001);