Real-time communication using PHP and WebSocket

With the development of Internet technology, more and more websites and applications are beginning to focus on the realization of real-time communication. The WebSocket protocol is regarded as an effective way to achieve real-time communication. This article will introduce how to use PHP and WebSocket to implement real-time communication functions.

What is WebSocket

WebSocket is a TCP-based protocol that can establish a persistent connection between the browser and the server to achieve two-way real-time communication. Unlike the HTTP protocol, the WebSocket protocol is a full-duplex protocol. It does not require the browser to send a request to receive the server's response, but can directly communicate in both directions.

Because WebSocket uses a long connection method, it can greatly improve data transmission efficiency and reduce the load on the server. In real-time communication scenarios, WebSocket has become an indispensable technology.

PHP and WebSocket

As a server-side language, PHP also has some frameworks that support WebSocket. Among the more famous ones are Rachet framework, swoole framework, etc.

In this article, we use the Rachet framework to implement real-time communication functions. The Rachet framework is an open source framework for PHP. It provides a server-side implementation of WebSocket and can support a variety of web servers, such as Apache, Nginx, etc.

Implementation steps

1. Install the Rachet framework

Use Composer to install the Rachet framework:

composer require cboden/ratchet

2. Write PHP code

The following is a simple PHP code that uses the Rachet framework to implement real-time communication:

<?php
use RatchetMessageComponentInterface;
use RatchetConnectionInterface;
use RatchetServerIoServer;
use RatchetHttpHttpServer;
use RatchetWebSocketWsServer;

require 'vendor/autoload.php';

class MyChat implements MessageComponentInterface {
    protected $clients;

    public function __construct() {
        $this->clients = new SplObjectStorage;
    }

    public function onOpen(ConnectionInterface $conn) {
        $this->clients->attach($conn);
        echo "New connection! ({$conn->resourceId})
";
    }

    public function onMessage(ConnectionInterface $from, $msg) {
        foreach ($this->clients as $client) {
            if ($from !== $client) {
                $client->send($msg);
            }
        }
    }

    public function onClose(ConnectionInterface $conn) {
        $this->clients->detach($conn);
        echo "Connection {$conn->resourceId} has disconnected
";
    }

    public function onError(ConnectionInterface $conn, Exception $e) {
        echo "An error has occurred: {$e->getMessage()}
";
        $conn->close();
    }
}

$server = IoServer::factory(
    new HttpServer(
        new WsServer(
            new MyChat()
        )
    ),
    8080
);

$server->run();

The code defines a class named MyChat, which implements the MessageComponentInterface interface in the Ratchet framework. It contains the following 4 methods:

• onOpen() is called when a new connection is established.
• onMessage() Called when the code receives a message.
• onClose() Called when the connection is closed.
• onError() Called when an error occurs.

Among them, the onOpen() method records the information established by the new connection, and the onMessage() method broadcasts the received message to all connected clients. end, and the onClose() method records connection closing information.

Finally, the code uses IoServer::factory() to create the server and enable monitoring.

3. Test

Start the server in the command line:

php chat-server.php

Then open multiple client pages in the browser, each page can send and receive real-time messages to achieve the effect of real-time communication.

Summary

This article introduces how to use PHP and Rachet framework to implement real-time communication functions. By using the WebSocket protocol, a persistent connection can be established between the browser and the server and two-way real-time communication can be achieved. In real-time communication scenarios, the use of WebSocket protocol has become an indispensable technology, and the Rachet framework provides us with a simple and efficient implementation method.

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