Gestion de sessions multi-utilisateurs et notifications en temps réel pour le système de chat en direct PHP

CREATE TABLE users (
    id INT PRIMARY KEY AUTO_INCREMENT,
    username VARCHAR(50) NOT NULL,
    password VARCHAR(255) NOT NULL
);

<?php
session_start();

// 数据库配置
$servername = "localhost";
$username = "root";
$password = "password";
$dbname = "chat";

// 连接数据库
$conn = new mysqli($servername, $username, $password, $dbname);
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}

// 获取用户输入的用户名和密码
$username = $_POST['username'];
$password = $_POST['password'];

// 查询用户信息
$sql = "SELECT id, username, password FROM users WHERE username = '$username'";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    // 验证密码
    $row = $result->fetch_assoc();
    if (password_verify($password, $row['password'])) {
        // 登录成功
        $_SESSION['user_id'] = $row['id'];
        $_SESSION['username'] = $row['username'];
        header("Location: chat.php");
    } else {
        // 密码错误
        echo "密码错误";
    }
} else {
    // 用户不存在
    echo "用户不存在";
}

$conn->close();
?>

<?php
session_start();

// 引入WebSocket类
require('WebSocket.php');

class Chat extends WebSocket
{
    // 客户端连接成功时触发
    protected function onOpen($client_id)
    {
        $user_id = $_SESSION['user_id'];
        $username = $_SESSION['username'];

        echo "用户 $username 连接成功
";
    }

    // 客户端发送消息时触发
    protected function onMessage($client_id, $message)
    {
        $user_id = $_SESSION['user_id'];
        $username = $_SESSION['username'];

        echo "用户 $username 发送消息 $message
";

        // 处理消息
        // ...
    }

    // 客户端关闭连接时触发
    protected function onClose($client_id)
    {
        $user_id = $_SESSION['user_id'];
        $username = $_SESSION['username'];

        echo "用户 $username 断开连接
";
    }
}

// 实例化Chat类并启动WebSocket服务器
$chat = new Chat();
$chat->start();
?>