How to make web socket daemons with PHP. Also in this talk we'll look at some similar topics like MQs

1. WebSockets with PHP:
Mission Impossible

2. Who am I?
✔ Yoan-Alexander Grigorov
✔ Proud PHP developer
✔ Likes to screw around with OOP

3. So what is a WebSocket after all?

5. WebSocket boosts UX
✔ Forget client pulls
✔ Forget long polling
✔ Make your application event based

6. What google say about
WebSockets:
✔ It's easy to build WebSocket server with node.js
✔ It's hard to build WebSocket server with PHP

7. Research! Research! Research!

8. Available tools for PHP
✔ Ratchet
✔ … it's only that. Seriously, it's only Ratchet
✔ Ok, there are some other libraries, all of them
named PHPWS

9. Ratchet
http://socketo.me

10. First things first

11. Install with composer

12. Setting up a server with Ratchet
<?php
use RatchetMessageComponentInterface;
use RatchetConnectionInterface;
class Handler implements MessageComponentInterface {
public function onOpen(ConnectionInterface $conn) {}
public function onMessage(ConnectionInterface $from, $msg) {}
public function onClose(ConnectionInterface $conn) {}
public function onError(ConnectionInterface $conn, Exception $e) {}
}

13. Setting up a server with Ratchet
<?php
use RatchetServerIoServer;
use RatchetHttpHttpServer;
use RatchetWebSocketWsServer;
$handler = new AppHandler();
$server = IoServer::factory(
new HttpServer(new WsServer(
$handler
)
), 8123);
$server->run();

14. In the browser
var ws = new WebSocket('ws://127.0.0.1:8123');
// ... in some event
ws.send('Гледай кви ръки, чуек!');
// ... listener for messages:
ws.onmessage = function (message) {
alert(message);
};

15. Let's make a chat!

16. What do we need?
✔ Keep all active connection objects
✔ When a connection sends a message, notify all
others
✔ On disconnect – remove connection object from
the in-memory cache (map)

17. Connections handling
<?php
class Handler implements MessageComponentInterface {
private $connections = [];
public function onOpen(ConnectionInterface $conn) {
$this->connections[$conn->resourceId] = $conn;
}
public function onMessage(ConnectionInterface $from, $msg) {
foreach ($this->connections as $receiver) {
$receiver->send($msg);
}
}
public function onClose(ConnectionInterface $conn) {
unset($this->connections[$conn->resourceId]);
}
}

18. That's it!

19. Keep an eye on:
✔ Run it like a daemon (/etc/init.d/skeleton)
✔ Fatal errors and exceptions – they kill the
daemon
✔ ORMs like Doctrine help you a lot

20. Doctrine uses Identity Map

22. Identity map gives you wings!

23. Web Servers and Web Sockets

24. Don't forget good old Ajax!

25. But how ajax could send messages
to the WebSocket server?

26. Message Queues

28. ZeroMQ
✔ Libzmq
✔ Has a PHP extension in PECL
✔ React/ZMQ (PHP wrapper)
✔ "react/zmq": "0.2.*|0.3.*" in Composer

29. What you need to know
✔ There are ZeroMQ listeners
– They use simple TCP
✔ There are ZeroMQ contexts (senders)
– They connect to ZeroMQ listeners and send
messages

30. What you need to know
✔ You need ZeroMQ listener in the WebSocket
daemon
✔ Ordinary PHP scripts send messages to the
listener
✔ Since ZeroMQ is in the WebSocket daemon, it
could easily interact with WebSocket
connections

31. Let's add ZeroMQ to our application!

32. Add callback for ZeroMQ messages
<?php
class Handler implements MessageComponentInterface
{
// ...
// this is CUSTOM method (not from interface)
public function onZMQMessage($message)
{
}
}

33. Add ZeroMQ listener to the daemon
<?php
use ...
$handler = new AppHandler();
$server = IoServer::factory(
new HttpServer(new WsServer(
$handler
)
), 8123);
// Listen on 127.0.0.1:4444
$context = new ReactZMQContext($server->loop);
$pull = $context->getSocket(ZMQ::SOCKET_PULL);
$pull->bind("tcp://127.0.0.1:4444");
$pull->on('message', function ($data) use ($handler) {
$handler->onZMQMessage($data);
});
$server->run();

34. In your Ajax server script
<?php
// ... add stuff to the database, other things...
// notify using ZeroMQ:
$context = new ZMQContext();
$socket = $context->getSocket(ZMQ::SOCKET_PUSH, 'pusher');
$socket->connect("tcp://127.0.0.1:4444");
$socket->send('Глей кви ръки! Туй аз ли съм!?');

35. Go! Try it yourself!

36. Working code examples from this talk:
https://github.com/sasquatch-mc/ratchet-example
(check the branches)

37. References
✔ http://socketo.me
✔ http://zeromq.org

38. Thanks and good luck!
✔ joan.grigorov@gmail.com
✔ bgscripts.com