facebook login将代码作为查询字符串中的变量返回

Question

I am using a Facebook login in one of my website using the sdk for PHP.

Sometimes the facebook login works and sometimes it doesn't.

Here is my index.php:

/// fb login area.....
include("facebook/src/facebook.php");

$facebook = new Facebook(array(
  'appId'  => '159326560901256',
  'secret' => 'c6b30bd2f80747b64d5b1d15a3da9e9c',
));

$user = $facebook->getUser();

$loginUrl = $facebook->getLoginUrl(array(
  'scope' => 'email',
  'redirect_uri' => 'http://xyz.com/login_fb.php'
));

<a href="<?=$loginUrl?>"><img class="fb_img" 
  src="images/fb_logo.png" width="153" height="38" /></a> 

it goes to login_fb.php:

https://www.facebook.com/dialog/oauth?client_id=123131231&redirect_uri=http%3A%2F%2Fxyz.com%2Flogin_fb.php&state=403bc8aaf9eaee4064e3cc27befc71ff&scope=email

now on login_fb.php i get this url:

login_fb.php?code=ASA&S^&*A^S&*A^S&*^A&*ASUAUIYSUIYASIYAUSYUIASA

and in $user I get 0

/// code for login_fb.php
include("facebook/src/facebook.php");

$facebook = new Facebook(array(
  'appId'  => '159326560901256',
  'secret' => 'c6b30bd2f80747b64d5b1d15a3da9e9c',
));


// Get User ID
$user = $facebook->getUser();
if ($user) {
    try {
        $user_profile = $facebook->api('/me');
    } 
    catch (FacebookApiException $e) {
        error_log($e);
        $user = null;
    }

    $logoutUrl = $facebook->getLogoutUrl(array(
      'next' => 'http://minuteville.com/index.php?val=fblogout'
    ));

Why isn't it working?

Answer 1

By adding the following line and using getAccessTokenFromCode in Facebook SDK, the problem can be resolved.

The acesss code expires. So getting new access code by exchanging code resolves the problem

$access_code = $facebook->getAccessTokenFromCode($_GET['code']);