Facebook SDK getAccessToken（）问题

Question

I have been having some trouble with the facebook SDK, specifically retrieving an access token. The App is set up on Facebook correctly and has been given permission. As far as I can tell, the code is correct and I am not sure what is going wrong with getAccessToken().

$facebook->getAccessToken(); is returning "12345678|abcdefghijklmnop", basically some kind of variable which is made up of the App ID and Secret ID separated by a |

$facebook->getUser(); is returning '0'

<?php
     require_once("facebook.php"); //Up-to-date SDK files from Git

     $app_id = "12345678"; //replaced with fake
     $app_secret = "abcdefghijklmnop"; //replaced with fake

     $facebook = new Facebook(array(
         'appId' => $app_id,
         'secret' => $app_secret,
         'cookie' => true; //I have tried 'false' here as well
     ));

     $token = $facebook->getAccessToken();
?>

Thank you in advance!

Answer 1

From Facebook SDK:

  public function getAccessToken() {
    if ($this->accessToken !== null) {
      return $this->accessToken;
    }

    $this->setAccessToken($this->getApplicationAccessToken());
    $user_access_token = $this->getUserAccessToken();
    if ($user_access_token) {
      $this->setAccessToken($user_access_token);
    }

    return $this->accessToken;
  }

  protected function getApplicationAccessToken() {
    return $this->appId.'|'.$this->appSecret;
  }

Your access token will be APP ID|APP SECRET which is the application token, or A RANDOM TOKEN HERE, which is the user access token, when you have a user signed:

$facebook->getUser();

When getUser() return 0 (which is same as false, and user not signed) you need to request a login, and authorization (if have not authorized yet) for your application:

if (!$facebook->getUser())
{
    $login_url = $facebook->getLoginUrl(array(
            'scope' => 'publish_stream' // Permissions goes here
        ) 
    );
?>
    <script type="text/javascript">
        top.location.href = " <?php echo $login_url; ?>";
    </script>
<?php
    exit;
}

see available permissions types here: https://developers.facebook.com/docs/authentication/permissions/