why Real Time?

Improve UX

Native apps to the Web

Real-time data

It's all about collaboration

Others

Make the slides for Real(Time)

http://192.168.0.100

Real Time in Computer Science

Also

Hard

Missing a deadline is a total system failure.

Firm

Infrequent deadline misses are tolerable, but may degrade the system's quality of service. The usefulness of a result is zero after its deadline.

Soft

The usefulness of a result degrades after its deadline, thereby degrading the system's quality of service.

Error

Real-time computing is sometimes misunderstood to be high-performance computing

Real-Time Discovery

network is always a bottleneck

Solutions

Past

Present

              new WebSocket('ws://chat.example.com/games');
            

The Good Parts

The Bad Parts

• No cross-browser
• Different implementations
• 3G can break websockets
• Sending invalid UTF-8 stops the connection
• Non-standard ports(firewalls)

Finding the right tool

• Browser support
• Usable from our main programming language
• Fast to develop/deploy
• Websockets and fallbacks
• Easy upgrade

Node.js

Socket.io

Ruby

EventMachine + Websockets

Python

Twisted

PHP

Ratchet

Redis

Pub/Sub

Socket.io

Server

              
                var io = require('socket.io').listen(80);

                io.sockets.on('connection', function (socket) {
                  socket.emit('news', { hello: 'world' });
                  socket.on('my other event', function (data) {
                    console.log(data);
                  });
                });
              
            

Client

              
                <script src="/socket.io/socket.io.js"></script>
                <script>
                  var socket = io.connect('http://localhost');
                  socket.on('news', function (data) {
                    console.log(data);
                    socket.emit('my other event', { my: 'data' });
                  });
                </script>