用户管理器/登录/注册/退出 [整合版]

带类型的请求:
如：serHandle.php?action=login

<?php
// 用户管理器/登录/注册/退出
// 1.开启会话
session_start();
// 2. 加载用户数据
require __DIR__ . '/../config/common.php';
$users = require DATA_PATH . '/users.php';
// 3. 获取get请求参数
$action = strtolower($_GET['action']);
// 4. 操作白名单
$allowOpts = ['login','register', 'logout'];
// 5. 操作结果默认值
$prompt = false;
// 6. 检测操作类型是否合法?
if (!in_array($action, $allowOpts)) {
    echo <<< TIPS
    <script>
        alert('操作类型非法');
        location.href='../login.php';
    </script>
    TIPS;
    die;
}
// 7. 判断要做什么
switch ($action) {
    // 7.1 登录
    case 'login':
        // 获取json,转array
        $json = file_get_contents('php://input');
        $user = json_decode($json, true);
        $email = $user['email'];
        $password = md5($user['password']);
        $result = array_filter($users, function ($user) use ($email, $password) {
            return  $user['email'] === $email && $user['password'] === $password;
        });
        if (count($result) === 1) {
            $prompt = true;
            // 登录成功,将用户信息写入session
            $_SESSION['user'] = array_pop($result);
        }
        break;
        // 7.2. 注册
    case 'register':
        $oriCount = count($users);
        $json = file_get_contents('php://input');
        $user = json_decode($json, true);
        $user['password'] = md5($user['password']);
        $user['id'] = count($users)+1;
        $users[] = $user;
        if (count($users) === $oriCount + 1) {
            $prompt = true;
        }
        break;
        // 7.3 退出
    case 'logout':
        if (session_destroy()) {
            $prompt = true;
        }
        break;
}
// 8. 结果返回前端
echo json_encode($prompt);
die;