Workerman development: How to implement an online whiteboard based on the WebSocket protocol-Workerman-php.cn

Workerman development: How to implement an online whiteboard based on the WebSocket protocol

王林

Release： 2023-11-07 10:42:49

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Workerman development: How to implement an online whiteboard based on the WebSocket protocol

Workerman Development: How to implement an online whiteboard based on the WebSocket protocol

Introduction:
Online collaboration and remote work have become an important trend in today's society, and Online whiteboards are a common collaboration tool that help users share and edit documents, graphics, and other information in real time from a distance. This article will introduce how to use Workerman to develop an online whiteboard based on the WebSocket protocol and provide specific code examples.

1. Preparation
First, we need to ensure that PHP and Workerman are installed. Workerman is a framework for creating high-performance PHP TCP/UDP asynchronous event-driven, very suitable for developing real-time communication applications, including online whiteboards based on the WebSocket protocol.

2. Build the server
First, we need to create a server to listen for WebSocket connections. The following is a simple sample code:

<?php
require_once __DIR__ . '/Workerman/Autoloader.php';
use WorkermanWorker;

// 创建一个Worker实例，监听8080端口
$ws_worker = new Worker("websocket://0.0.0.0:8080");

// 启动4个进程对外提供服务
$ws_worker->count = 4;

// 当客户端连接成功时触发的回调函数
$ws_worker->onConnect = function($connection) {
    echo "New connection
";
};

// 当收到客户端消息时触发的回调函数
$ws_worker->onMessage = function($connection, $data) {
    // 处理客户端发送的消息
    // ...
};

// 当客户端断开连接时触发的回调函数
$ws_worker->onClose = function($connection) {
    echo "Connection closed
";
};

// 运行Worker
Worker::runAll();

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3. Processing client messages
When the client sends a message, we need to broadcast it to all online clients. The following is a simple message processing code example:

// 当收到客户端消息时触发的回调函数
$ws_worker->onMessage = function($connection, $data) use ($ws_worker) {
    // 广播消息给所有在线的客户端
    foreach($ws_worker->connections as $client_conn) {
        $client_conn->send($data);
    }
};

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4. Implementing the online whiteboard function
In order to implement the online whiteboard function, we need to define several protocols to handle drawing operations. The following is a simple sample code:

// 当收到客户端消息时触发的回调函数
$ws_worker->onMessage = function($connection, $data) use ($ws_worker) {
    // 解析客户端发送的消息
    $json_data = json_decode($data, true);

    // 根据消息类型进行不同的处理
    switch ($json_data['type']) {
        case 'draw':
            // 广播绘图命令给所有在线的客户端
            foreach($ws_worker->connections as $client_conn) {
                $client_conn->send($data);
            }
            break;
        case 'clear':
            // 清除白板命令处理
            // ...
            break;
        // 其他命令处理
        // ...
    }
};

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5. Client code example
Finally, we also need to write a simple front-end page to test our online whiteboard. The following is a sample code based on JavaScript:

<!DOCTYPE html>
<html>
<head>
    <title>Online Whiteboard</title>
</head>
<body>
    <canvas id="whiteboard" width="800" height="500"></canvas>
    <script>
        var canvas = document.getElementById("whiteboard");
        var context = canvas.getContext("2d");

        var ws = new WebSocket("ws://localhost:8080");

        ws.onopen = function() {
            console.log("Connected to server");
        };

        ws.onmessage = function(event) {
            var data = JSON.parse(event.data);

            // 根据消息类型进行不同的处理
            switch (data.type) {
                case 'draw':
                    // 处理绘图命令
                    var x = data.x;
                    var y = data.y;
                    // ...
                    break;
                // 其他命令处理
                // ...
            }
        };

        canvas.addEventListener("mousemove", function(event) {
            // 获取鼠标位置
            var x = event.clientX;
            var y = event.clientY;

            // 绘图命令
            var data = {
                type: 'draw',
                x: x,
                y: y
            };

            // 发送绘图命令给服务器
            ws.send(JSON.stringify(data));
        });
    </script>
</body>
</html>

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Conclusion:
Through the above code example, we can implement an online whiteboard based on Workerman and WebSocket protocols, and users can share and edit drawing information in real time at different locations . I hope this article will help you understand how to use Workerman to develop an online whiteboard.

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