实现PHP WebSocket多设备实时更新：构建Pub/Sub系统

<?php
// server.php
require __DIR__ . '/vendor/autoload.php'; // 假设你使用 Composer

use WebSocket\Server;

$server = new Server([
    'host' => '0.0.0.0', // 监听所有接口
    'port' => 8080,      // WebSocket端口
    'maxClients' => 1000 // 最大客户端连接数
]);

// 存储所有连接的客户端
$clients = [];
// 存储频道订阅信息
$channels = [];

$server->on('connect', function ($client) use (&$clients) {
    echo "Client connected: " . $client->id . "\n";
    $clients[$client->id] = $client;
    // 可以在这里处理客户端的初始订阅请求
});

$server->on('message', function ($client, $message) use (&$clients, &$channels, $server) {
    echo "Received message from client " . $client->id . ": " . $message . "\n";
    $data = json_decode($message, true);

    if (isset($data['type'])) {
        switch ($data['type']) {
            case 'subscribe':
                // 客户端订阅频道
                if (isset($data['channel'])) {
                    $channel = $data['channel'];
                    if (!isset($channels[$channel])) {
                        $channels[$channel] = [];
                    }
                    $channels[$channel][$client->id] = $client;
                    echo "Client " . $client->id . " subscribed to channel " . $channel . "\n";
                }
                break;
            case 'broadcast':
                // PHP应用（或其他客户端）发送广播消息
                if (isset($data['channel']) && isset($data['message'])) {
                    $targetChannel = $data['channel'];
                    $broadcastMessage = json_encode([
                        'channel' => $targetChannel,
                        'message' => $data['message']
                    ]);
                    echo "Broadcasting to channel " . $targetChannel . ": " . $broadcastMessage . "\n";

                    if (isset($channels[$targetChannel])) {
                        foreach ($channels[$targetChannel] as $subscriberClient) {
                            // 确保不要将广播消息发回给发送者（如果发送者也是一个订阅者）
                            // 对于PHP应用作为发布者的情况，通常不会收到自己发的消息
                            $server->send($subscriberClient, $broadcastMessage);
                        }
                    }
                }
                break;
            // 可以添加其他消息类型，如心跳、认证等
        }
    }
});

$server->on('disconnect', function ($client) use (&$clients, &$channels) {
    echo "Client disconnected: " . $client->id . "\n";
    unset($clients[$client->id]);

    // 从所有订阅频道中移除该客户端
    foreach ($channels as $channelName => &$channelClients) {
        unset($channelClients[$client->id]);
        if (empty($channelClients)) {
            unset($channels[$channelName]); // 如果频道为空，可以移除
        }
    }
});

$server->start();

// client.js
const ws = new WebSocket('ws://localhost:8080'); // 替换为你的WebSocket服务器地址

ws.onopen = () => {
    console.log('已连接到WebSocket服务器');
    // 连接成功后，发送订阅消息到服务器
    ws.send(JSON.stringify({ type: 'subscribe', channel: 'my-channel' }));
};

ws.onmessage = (event) => {
    const data = JSON.parse(event.data);
    console.log('收到消息:', data);

    if (data.channel === 'my-channel') {
        // 根据收到的消息更新UI
        const updateElement = document.getElementById('realtime-updates');
        if (updateElement) {
            updateElement.innerHTML += `<p>新消息：${data.message}</p>`;
        }
    }
};

ws.onclose = () => {
    console.log('与WebSocket服务器断开连接');
    // 可以在这里实现重连逻辑
};

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

// 页面中需要一个元素来显示实时更新
// <div id="realtime-updates"></div>

<?php
// ajax_handler.php (你的PHP业务逻辑文件)
require __DIR__ . '/vendor/autoload.php'; // 假设你使用 Composer

use WebSocket\Client; // 假设你使用了一个WebSocket客户端库，例如 textalk/websocket

if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['action'])) {
    // 1. 执行你的业务逻辑（例如，更新数据库）
    // ...
    $newStatus = "订单ID " . rand(1000, 9999) . " 已更新到 '已发货' 状态！";

    // 2. 连接到WebSocket服务器并发送广播消息
    try {
        $client = new Client('ws://localhost:8080'); // 替换为你的WebSocket服务器地址
        $client->send(json_encode([
            'type' => 'broadcast',
            'channel' => 'my-channel',
            'message' => $newStatus
        ]));
        $client->close();

        echo json_encode(['status' => 'success', 'message' => '更新已触发并广播']);
    } catch (Exception $e) {
        error_log("WebSocket广播失败: " . $e->getMessage());
        echo json_encode(['status' => 'error', 'message' => '无法连接到WebSocket服务器或发送消息']);
    }
} else {
    echo json_encode(['status' => 'error', 'message' => '无效请求']);
}
?>