Slim Framwork在facebook画布应用程序中返回404

Question

我想尝试使用Slim Framework进行测试路由等。所以除了我发送Facebook通知时强制用户访问Facebook画布游戏页面，它的工作效果很好。当您输入链接时，Slim正在呈现404。

$app->notFound(function () use ($app) {
    ... THIS IS WHAT I GET ...
});

在php中我得到：

$_GET = Array
    (
        [fb_source] => notification
        [request_ids] => SOME_ID
        [ref] => notif
        [app_request_type] => user_to_user
        [notif_t] => app_request
    )
$_POST =Array
    (
        [signed_request] => A_SIGNED_REQUEST
        [fb_locale] => my_LO
    )
$_COOKIE = Array
    (
        ...SOME COOKIE  STUFF HERE...
    )
$_REQUEST = Array
    (
        [fb_source] => notification
        [request_ids] => SOME_ID
        [ref] => notif
        [app_request_type] => user_to_user
        [notif_t] => app_request
        [signed_request] => A_SIGNED_REQUEST
        [fb_locale] => my_LO
    )

但是当我尝试很多

的变种时

$app->GET('/:fb_source', function ($fb_source) use ($app) {
   ... 
});

我仍然坚持使用404 ......现在我做错了什么？