如何使用 PHP 实现用户注册和密码重置

<?php
// 数据库连接参数
$db_host = "localhost";
$db_username = "root";
$db_password = "password";
$db_name = "mydb";

// 创建数据库连接
$conn = new mysqli($db_host, $db_username, $db_password, $db_name);
if ($conn->connect_error) {
    die("数据库连接失败: " . $conn->connect_error);
}

// 获取用户提交的注册信息
$username = $_POST["username"];
$email = $_POST["email"];
$password = $_POST["password"];

// 检查用户名是否已被注册
$sql = "SELECT * FROM users WHERE username = '$username'";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
    echo "该用户名已被注册";
} else {
    // 将用户信息插入数据库
    $sql = "INSERT INTO users (username, email, password) VALUES ('$username', '$email', '$password')";
    if ($conn->query($sql) === true) {
        echo "注册成功";
    } else {
        echo "注册失败: " . $conn->error;
    }
}

// 关闭数据库连接
$conn->close();
?>

<?php
// 数据库连接参数
$db_host = "localhost";
$db_username = "root";
$db_password = "password";
$db_name = "mydb";

// 创建数据库连接
$conn = new mysqli($db_host, $db_username, $db_password, $db_name);
if ($conn->connect_error) {
    die("数据库连接失败: " . $conn->connect_error);
}

// 获取用户提交的邮箱地址
$email = $_POST["email"];

// 检查该邮箱地址是否存在于数据库中
$sql = "SELECT * FROM users WHERE email = '$email'";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
    // 生成一个随机的新密码
    $new_password = generateRandomPassword();

    // 更新用户密码
    $sql = "UPDATE users SET password = '$new_password' WHERE email = '$email'";
    if ($conn->query($sql) === true) {
        echo "密码已重置，请查收新密码邮件";
        sendEmail($email, $new_password); // 发送邮件
    } else {
        echo "密码重置失败: " . $conn->error;
    }
} else {
    echo "该邮箱地址不存在";
}

// 关闭数据库连接
$conn->close();

// 生成随机密码的函数
function generateRandomPassword() {
    $characters = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
    $password = '';
    for ($i = 0; $i < 8; $i++) {
        $index = rand(0, strlen($characters) - 1);
        $password .= $characters[$index];
    }
    return $password;
}

// 发送邮件的函数
function sendEmail($email, $password) {
    // 使用邮件库发送邮件
    // 这里只是示例，具体实现需使用合适的邮件库或服务
    // 使用 PHPMailer 实现的例子：
    /*
    require 'PHPMailer/PHPMailerAutoload.php';
    $mail = new PHPMailer;
    $mail->isSMTP();
    $mail->SMTPAuth = true;
    $mail->Host = 'smtp.gmail.com';
    $mail->Username = 'your-email@gmail.com';
    $mail->Password = 'your-email-password';
    $mail->SMTPSecure = 'tls';
    $mail->Port = 587;
    $mail->setFrom('your-email@gmail.com', 'Your Name');
    $mail->addAddress($email);
    $mail->Subject = 'New Password';
    $mail->Body = 'Your new password is: ' . $password;
    if (!$mail->send()) {
        echo '邮件发送失败: ' . $mail->ErrorInfo;
    }
    */
}
?>