肥皂服务器不能在Laravel 5.2中工作

我正在尝试在laravel 5.2中创建一个soap服务器.这是我的代码：
SoapController.PHP的内容：

<?PHP namespace Giant\Http\Controllers;

class SoapController extends Controller {

    public function __construct() {
        parent::__construct();
        ini_set('soap.wsdl_cache_enabled', 0);
        ini_set('soap.wsdl_cache_ttl', 0);
        ini_set('default_socket_timeout', 300);
        ini_set('max_execution_time', 0);
    }

    public function server() {
        $location = url('server'); // http://payment.dev/server
        $namespace = $location;
        $class = "\\Giant\\Http\\Controllers\\HelloWorld";

        $wsdl = new \WSDL\WSDLCreator($class, $location);
        $wsdl->setNamespace($namespace);

        if (isset($_GET['wsdl'])) {
            $wsdl->renderWSDL();
            exit;
        }

        $wsdl->renderWSDLService();

        $wsdlUrl = url('wsdl/server.wsdl');
        $server = new \SoapServer(
            url('server?wsdl'),
            array(
                'exceptions' => 1,
                'trace' => 1,
            )
        );

        $server->setClass($class);
        $server->handle();
        exit;
    }

    public function client() {
        $wsdl = url('server?wsdl');
        $client = new \SoapClient($wsdl);

        try {
            $res = $client->hello('world');
            dd($res);
        } catch (\Exception $ex) {
            dd($ex);
        }
    }
}


class HelloWorld {
    /**
     * @WebMethod
     * @desc Hello Web-Service
     * @param string $name
     * @return string $helloMessage
     */
    public function hello($name) {
        return "hello {$name}";
    }
}

我的wsdl文件是：wsdl

而我的路线：

Route::any('/server', 'SoapController@server');
Route::any('/client', 'SoapController@client');

结果是：

Internal Server Error