试图使用facebook-php-sdk库来检索Facebook的帖子

我正在将Facebook的帖子拉到我的网站上，以便我可以以我自己的格式保存和显示。我正在尝试使用Facebook开发人员页面上的Facebook-php-sdk库。我需要图书馆后，我使用以下代码：

I am trying to pull facebook posts onto my site so that I can save and display it in my own format. I am trying to use the facebook-php-sdk library, found on the Facebook Developer pages. I used the following code after I required the library:

$facebook = new Facebook(array(
'appId'  => 'MY APP ID',
'secret' => 'MY APP SECRET',
));

// Get User ID
$user = $facebook->getUser();
print_r($facebook);
print_r($user);

print_r到$ facebook显示了一个完整的Facebook对象，所以我知道它正在创建。

The print_r into $facebook showed me a full facebook object, so I know its being created properly.

 object(Facebook)#325 (9) { ["sharedSessionID":protected]=> NULL ["appId":protected]=> string(15) "[MYAPPID]" ["appSecret":protected]=> string(32) "[MYAPPSECRET]" ["user":protected]=> int(0) ["signedRequest":protected]=> NULL ["state":protected]=> NULL ["accessToken":protected]=> string(48) "[MYAPPID]|[MYAPPSECRET]" ["fileUploadSupport":protected]=> bool(false) ["trustForwarded":protected]=> bool(false) }

（我从上面的报价中拿出了我的应用程序ID和应用程序密码）。

(I took my app id and app secret codes out of the quote above).

但是，print_r到$ user显示

However, the print_r into $user displayed

int(0).

我在这里缺少什么？