$middleware = function($request, $next) {
    // 執(zhí)行一些額外的邏輯（例如記錄日志、驗(yàn)證身份等）
    echo "Executing middleware before request\n";
    
    // 調(diào)用下一個(gè)中間件或路由處理函數(shù)
    $response = $next($request);
    
    // 執(zhí)行一些后續(xù)邏輯（例如清理資源、設(shè)置響應(yīng)頭等）
    echo "Executing middleware after request\n";
    
    return $response;
};

// 定義路由和處理邏輯
$routes = [
    '/home' => function() {
        echo "Welcome to the home page";
    },
    '/about' => function() {
        echo "About Us";
    },
    '/contact' => function() {
        echo "Contact Us";
    }
];
// 獲取當(dāng)前請(qǐng)求的路由
$requestUrl = $_SERVER['REQUEST_URI'];
// 檢查請(qǐng)求的路由是否存在，并執(zhí)行相應(yīng)的處理邏輯
if (isset($routes[$requestUrl]) && is_callable($routes[$requestUrl])) {
    $closure = $routes[$requestUrl];
    $closure();
} else {
    echo "404 Not Found";
}

$numbers = [1, 2, 3, 4, 5];
// 使用閉包將數(shù)組中的每個(gè)元素乘以2
$multipliedNumbers = array_map(function($num) {
    return $num * 2;
}, $numbers);
print_r($multipliedNumbers);
// 使用閉包過濾出所有大于3的元素
$filteredNumbers = array_filter($numbers, function($num) {
    return $num > 3;
});
print_r($filteredNumbers);

function processAsyncRequest($callback)
{
    // 模擬異步請(qǐng)求處理
    sleep(3);
    $response = "Async response";
    
    // 調(diào)用回調(diào)函數(shù)處理響應(yīng)
    $callback($response);
}
// 定義回調(diào)函數(shù)作為閉包
$callback = function($response) {
    echo "Received response: " . $response;
};
// 調(diào)用函數(shù)并傳入閉包作為回調(diào)
processAsyncRequest($callback);