实时应用中用户在线状态管理与会话销毁时的数据清理策略

// server.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 $activeUsers; // 存储 ConnectionInterface 和用户ID的映射

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

    public function onOpen(ConnectionInterface $conn) {
        $this->clients->attach($conn);
        echo "New connection! ({$conn->resourceId})\n";
        // 在此处可以进行用户认证，并将用户ID与$conn关联
        // 例如：$conn->userId = $authenticatedUserId;
        // 假设已通过某种方式获取到用户ID
        // $this->activeUsers[$conn->resourceId] = $conn->userId;
        // 数据库操作：将用户ID添加到 activeuserlist
        // $this->addToActiveUserList($conn->userId);
    }

    public function onMessage(ConnectionInterface $from, $msg) {
        // 处理消息，例如广播给其他用户
        // ...
    }

    public function onClose(ConnectionInterface $conn) {
        $this->clients->detach($conn);
        echo "Connection {$conn->resourceId} has disconnected\n";
        // 获取断开连接的用户ID
        // $userId = $this->activeUsers[$conn->resourceId] ?? null;
        // if ($userId) {
        //     数据库操作：从 activeuserlist 中移除该用户ID
        //     $this->removeFromActiveUserList($userId);
        //     unset($this->activeUsers[$conn->resourceId]);
        // }
    }

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

    // 辅助函数，用于数据库操作（需要替换为实际的数据库连接和操作）
    // private function addToActiveUserList($userId) {
    //     // INSERT INTO activeuserlist (user_id, status) VALUES (:userId, 'online');
    // }
    // private function removeFromActiveUserList($userId) {
    //     // DELETE FROM activeuserlist WHERE user_id = :userId;
    // }
}

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

$server->run();

// client.js
var conn = new WebSocket('ws://localhost:8080');

conn.onopen = function(e) {
    console.log("Connection established!");
    // 可以在这里发送用户认证信息给服务器
    // conn.send(JSON.stringify({ type: 'auth', userId: currentUserId }));
};

conn.onmessage = function(e) {
    console.log(e.data);
};

conn.onclose = function(e) {
    console.log("Connection closed!");
    // 可以在这里处理连接断开后的客户端逻辑
};

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

// client.js
function sendHeartbeat() {
    fetch('/api/heartbeat.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
            // 可以包含认证信息，例如Session ID或Token
        },
        body: JSON.stringify({ userId: currentUserId }) // 假设currentUserId已定义
    })
    .then(response => response.json())
    .then(data => {
        if (data.status === 'success') {
            console.log('Heartbeat sent successfully.');
        } else {
            console.error('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);

// 页面关闭或刷新时尝试发送一个最终的心跳或通知
window.addEventListener('beforeunload', function() {
    // 理论上，可以在这里发一个同步请求通知下线，但实际操作中不推荐，因为会阻塞页面关闭
    // 且浏览器可能阻止同步XHR在beforeunload中发送
    // 更好的方式是依赖服务器端的超时清理机制
});

<?php
// heartbeat.php
header('Content-Type: application/json');

// 假设已建立数据库连接 $pdo
$pdo = new PDO('mysql:host=localhost;dbname=your_db', 'user', 'password');
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

// 获取用户ID (从session或POST数据中获取，这里简化为POST)
$input = json_decode(file_get_contents('php://input'), true);
$userId = $input['userId'] ?? null;

if (!$userId) {
    echo json_encode(['status' => 'error', 'message' => 'User ID is required.']);
    exit;
}

try {
    // 更新用户的最后活跃时间
    $stmt = $pdo->prepare("INSERT INTO activeuserlist (user_id, last_active_time) VALUES (:userId, NOW()) ON DUPLICATE KEY UPDATE last_active_time = NOW()");
    $stmt->execute([':userId' => $userId]);

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

// 清理离线用户的函数 (可以在这里调用，或由定时任务调用)
function cleanupInactiveUsers($pdo, $timeoutMinutes = 5) {
    $stmt = $pdo->prepare("DELETE FROM activeuserlist WHERE last_active_time < NOW() - INTERVAL :timeoutMinutes MINUTE");
    $stmt->execute([':timeoutMinutes' => $timeoutMinutes]);
    return $stmt->rowCount();
}

// 可以在每次心跳请求后尝试清理，但更推荐使用Cron Job
// cleanupInactiveUsers($pdo, 5);
?>

# 每隔5分钟执行一次PHP脚本来清理离线用户
*/5 * * * * /usr/bin/php /path/to/your/cleanup_script.php

<?php
// cleanup_script.php
$pdo = new PDO('mysql:host=localhost;dbname=your_db', 'user', 'password');
$pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);

$timeoutMinutes = 5; // 定义离线超时时间
$stmt = $pdo->prepare("DELETE FROM activeuserlist WHERE last_active_time < NOW() - INTERVAL :timeoutMinutes MINUTE");
$stmt->execute([':timeoutMinutes' => $timeoutMinutes]);

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