管理用户在线状态：会话销毁时数据库记录的同步删除策略

// server.php (WebSocket 服务器端)
<?php
require dirname(__DIR__) . '/vendor/autoload.php';

use Ratchet\MessageComponentInterface;
use Ratchet\ConnectionInterface;
use Ratchet\Server\IoServer;
use Ratchet\Http\HttpServer;
use Ratchet\WebSocket\WsServer;

class Chat implements MessageComponentInterface {
    protected $clients;
    protected $onlineUsers; // 存储用户ID与ConnectionInterface的映射

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

    public function onOpen(ConnectionInterface $conn) {
        // 当有新连接打开时
        $this->clients->attach($conn);
        echo "New connection! ({$conn->resourceId})\n";

        // 假设用户ID通过某种方式（如URL参数或第一次消息）传递
        // 这里简化为模拟，实际应用中需验证用户身份
        // $userId = getUserFromSessionOrToken($conn); 
        // $this->onlineUsers[$userId] = $conn;

        // 示例：首次连接时，客户端发送一个包含用户ID的JSON消息
        // $conn->send(json_encode(['type' => 'init', 'userId' => 123])); 
        // 在实际应用中，这里需要等待客户端发送用户身份信息
    }

    public function onMessage(ConnectionInterface $from, $msg) {
        $data = json_decode($msg, true);

        if (isset($data['type']) && $data['type'] === 'login' && isset($data['userId'])) {
            $userId = $data['userId'];
            $this->onlineUsers[$userId] = $from;
            // 连接数据库，将用户ID插入 activeuserlist 表
            // 示例：
            // $pdo = new PDO('mysql:host=localhost;dbname=chat_db', 'user', 'pass');
            // $stmt = $pdo->prepare("INSERT INTO activeuserlist (user_id, connection_id) VALUES (?, ?) ON DUPLICATE KEY UPDATE connection_id = ?");
            // $stmt->execute([$userId, $from->resourceId, $from->resourceId]);
            echo "User {$userId} logged in via WebSocket.\n";
        }
        // ... 处理其他消息，如聊天消息 ...
    }

    public function onClose(ConnectionInterface $conn) {
        // 当连接关闭时
        $this->clients->detach($conn);
        echo "Connection {$conn->resourceId} has disconnected\n";

        // 查找是哪个用户断开了连接
        $disconnectedUserId = null;
        foreach ($this->onlineUsers as $userId => $userConn) {
            if ($userConn === $conn) {
                $disconnectedUserId = $userId;
                unset($this->onlineUsers[$userId]);
                break;
            }
        }

        if ($disconnectedUserId) {
            // 连接数据库，从 activeuserlist 表中删除该用户ID
            // 示例：
            // $pdo = new PDO('mysql:host=localhost;dbname=chat_db', 'user', 'pass');
            // $stmt = $pdo->prepare("DELETE FROM activeuserlist WHERE user_id = ?");
            // $stmt->execute([$disconnectedUserId]);
            echo "User {$disconnectedUserId} logged out (disconnected).\n";
        }
    }

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

$server = IoServer::factory(
    new HttpServer(
        new WsServer(
            new Chat()
        )
    ),
    8080 // WebSocket 端口
);

$server->run();

// client.js (浏览器端)
const userId = 123; // 假设从后端获取当前登录用户ID
const conn = new WebSocket('ws://localhost:8080');

conn.onopen = function(e) {
    console.log("Connection established!");
    // 发送用户ID给服务器，以便服务器知道哪个用户连接了
    conn.send(JSON.stringify({ type: 'login', userId: userId }));
};

conn.onmessage = function(e) {
    console.log(e.data);
    // 处理服务器发送的消息
};

conn.onclose = function(e) {
    console.log("Connection closed!");
    // 可以在这里进行一些清理工作，但数据库更新由服务器处理
};

conn.onerror = function(e) {
    console.error("WebSocket Error:", e);
};

// 当用户显式点击登出按钮时，可以主动关闭WebSocket连接
document.getElementById('logoutButton').addEventListener('click', function() {
    conn.close(); // 这会触发服务器端的 onClose 事件
    // 也可以同时发送一个登出请求到HTTP后端，清理会话
    fetch('/logout.php', { method: 'POST' });
});

// client.js (浏览器端)
function sendHeartbeat() {
    fetch('/heartbeat.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            // 如果需要，可以添加认证头
        },
        // body: JSON.stringify({ userId: currentUserId }) // 如果服务器需要明确的用户ID
    })
    .then(response => response.json())
    .then(data => {
        if (data.status === 'success') {
            console.log("Heartbeat sent successfully.");
        } else {
            console.warn("Heartbeat failed:", data.message);
        }
    })
    .catch(error => {
        console.error("Error sending heartbeat:", error);
    });
}

// 每隔 30 秒发送一次心跳
setInterval(sendHeartbeat, 30 * 1000);

// 用户显式登出时，立即发送登出请求
document.getElementById('logoutButton').addEventListener('click', function() {
    fetch('/logout.php', { method: 'POST' })
    .then(() => {
        // 清理客户端状态，重定向等
        window.location.href = '/login.php';
    });
});

// heartbeat.php
<?php
session_start(); // 确保会话已启动

header('Content-Type: application/json');

if (!isset($_SESSION['user_id'])) {
    echo json_encode(['status' => 'error', 'message' => 'Not authenticated.']);
    exit;
}

$userId = $_SESSION['user_id'];
$currentTime = date('Y-m-d H:i:s');

try {
    $pdo = new PDO('mysql:host=localhost;dbname=chat_db', 'user', 'pass');
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 插入或更新用户的活跃时间
    $stmt = $pdo->prepare("INSERT INTO activeuserlist (user_id, last_active) VALUES (?, ?) ON DUPLICATE KEY UPDATE last_active = ?");
    $stmt->execute([$userId, $currentTime, $currentTime]);

    echo json_encode(['status' => 'success', 'message' => 'Active status updated.']);

} catch (PDOException $e) {
    echo json_encode(['status' => 'error', 'message' => 'Database error: ' . $e->getMessage()]);
}
?>

// cron_job_cleanup.php
<?php
// 这个脚本应该通过服务器的 Cron Job 每隔几分钟运行一次

$inactiveThreshold = time() - (5 * 60); // 5分钟前的时间戳

try {
    $pdo = new PDO('mysql:host=localhost;dbname=chat_db', 'user', 'pass');
    $pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

    // 删除 last_active 超过阈值的用户
    $stmt = $pdo->prepare("DELETE FROM activeuserlist WHERE UNIX_TIMESTAMP(last_active) < ?");
    $stmt->execute([$inactiveThreshold]);

    echo "Cleaned up " . $stmt->rowCount() . " inactive users.\n";

} catch (PDOException $e) {
    echo "Database error during cleanup: " . $e->getMessage() . "\n";
}
?>

# 每隔 5 分钟执行一次 PHP 清理脚本
*/5 * * * * /usr/bin/php /path/to/your/cron_job_cleanup.php >> /var/log/chat_cleanup.log 2>&1