$app = function ($request) {

    echo $request . "\n";

    return "项目运行中.....";

};

// 现在想在$app中加入一些额外的信息

$checkToken = function ($request, Closure $next) {

    echo "检测token中....\n";

    $response = $next($request);

    echo "检测token完成\n";

    return $response;

};

$checkPermission = function ($request, Closure $next) {

    echo "检测权限中....\n";

    $response = $next($request);

    echo "检测权限完成\n";

    return $response;

};

$middleware = [

    $checkToken,

    $checkPermission

];

$next = $app;

foreach ($middleware as $m) {

    $next = function ($request) use ($m, $next) {

        return $m($request, $next);

    };

}

$res = $next("haha");

echo $res;