利用PHP WebSocket实现多设备实时更新：构建Pub/Sub系统教程

// 概念性 PHP WebSocket 服务器核心逻辑 (使用一个简化的伪代码表示)
// 实际生产环境应使用成熟的库，如 RatchetPHP 或 Swoole WebSocket Server
class MyWebSocketServer {
    private $clients = []; // 存储所有连接的客户端
    private $channels = []; // 存储频道订阅关系

    public function start($port) {
        // 监听指定端口，接受新的WebSocket连接
        // ...
        $this->onNewConnection(function($conn) {
            $this->clients[] = $conn;
            echo "新客户端连接: " . $conn->resourceId . "\n";

            $conn->onMessage(function($msg) use ($conn) {
                $data = json_decode($msg, true);
                if (isset($data['type'])) {
                    switch ($data['type']) {
                        case 'subscribe':
                            $channel = $data['channel'];
                            if (!isset($this->channels[$channel])) {
                                $this->channels[$channel] = [];
                            }
                            $this->channels[$channel][$conn->resourceId] = $conn;
                            echo "客户端 " . $conn->resourceId . " 订阅了频道 " . $channel . "\n";
                            break;
                        case 'broadcast':
                            $this->broadcastToChannel($data['channel'], $data['message']);
                            break;
                        // ... 其他消息类型
                    }
                }
            });

            $conn->onClose(function() use ($conn) {
                // 移除断开连接的客户端及其订阅
                foreach ($this->channels as $channelName => &$subscribers) {
                    unset($subscribers[$conn->resourceId]);
                }
                unset($this->clients[$conn->resourceId]);
                echo "客户端断开: " . $conn->resourceId . "\n";
            });
        });
        // ... 启动服务器循环
    }

    public function broadcastToChannel($channel, $message) {
        if (isset($this->channels[$channel])) {
            foreach ($this->channels[$channel] as $client) {
                $client->send(json_encode([
                    'type' => 'broadcast',
                    'channel' => $channel,
                    'message' => $message
                ]));
            }
        }
    }
}

// 实例化并启动服务器 (实际代码会更复杂)
// $server = new MyWebSocketServer();
// $server->start(8080);

// client.js
const WEBSOCKET_SERVER_URL = 'ws://localhost:8080'; // 替换为您的WebSocket服务器地址

const ws = new WebSocket(WEBSOCKET_SERVER_URL);

ws.onopen = () => {
    console.log('成功连接到WebSocket服务器');
    // 连接成功后，发送订阅请求
    // 假设我们订阅一个名为 'my_channel' 的频道
    ws.send(JSON.stringify({ type: 'subscribe', channel: 'my_channel' }));
};

ws.onmessage = (event) => {
    const data = JSON.parse(event.data);
    if (data.type === 'broadcast' && data.channel === 'my_channel') {
        console.log('收到实时更新消息:', data.message);
        // 在这里处理更新，例如：
        // document.getElementById('status-message').innerText = data.message;
        // alert('您有新的更新：' + data.message);
    }
};

ws.onclose = () => {
    console.log('WebSocket连接已关闭');
    // 可以尝试重连
};

ws.onerror = (error) => {
    console.error('WebSocket发生错误:', error);
};

// update_handler.php (由AJAX请求触发的PHP脚本)

require 'vendor/autoload.php'; // 假设您使用Composer安装了WebSocket客户端库

use WebSocket\Client; // 假设您使用了一个名为 'web-socket-client' 的库

// 1. 处理业务逻辑 (例如，更新数据库)
// ...
echo "业务逻辑处理完成。\n";

// 2. 向WebSocket服务器发送广播消息
try {
    $wsClient = new Client("ws://localhost:8080"); // 连接到WebSocket服务器
    $message = json_encode([
        'type' => 'broadcast',
        'channel' => 'my_channel', // 指定要广播的频道
        'message' => '您的数据已更新，请刷新页面！' // 实际更新内容
    ]);
    $wsClient->send($message);
    $wsClient->close();
    echo "广播消息已发送到WebSocket服务器。\n";
} catch (\Exception $e) {
    error_log("发送WebSocket消息失败: " . $e->getMessage());
    echo "发送实时更新失败。\n";
}

// 3. (可选) 响应原始AJAX请求
echo json_encode(['status' => 'success', 'message' => '操作成功']);