title: Facebook PHP SDK v5 - AccessToken expiration date
body: <p>I have two PHP files for making a login-link and receiving the access token (callback). My problem is, I cannot receive or get the expiration date of the access token.</p>
  
  <p>This is my script for creating a link:</p>
  
  <pre><code>&lt;?php
  session_start();
  
  define('FACEBOOK_SDK_V4_SRC_DIR', __DIR__ . '/facebook/');      
  require_once __DIR__ . '/autoload.php';
  
  $fb = new Facebook\Facebook( array('app_id' =&gt; 'XX', 'app_secret' =&gt; 'XX', 'default_graph_version' =&gt; 'v2.5'));
  
  $permissions = ['email', 'user_likes', 'user_birthday', 'manage_pages ', 'user_photos', 'publish_actions', 'publish_pages' ];
  
  $helper = $fb -&gt; getRedirectLoginHelper();
  $loginUrl = $helper -&gt; getLoginUrl('blabla/facebook-login-callback.php', $permissions);
  
  echo '&lt;a href="' . $loginUrl . '"&gt;Log in with Facebook!&lt;/a&gt;'; ?&gt;
  </code></pre>
  
  <p><strong>This works fine</strong>, my callback file is called.</p>
  
  <pre><code>&lt;?php
  
  session_start();
  
  define('FACEBOOK_SDK_V4_SRC_DIR', __DIR__ . '/facebook/');
  require __DIR__ . '/autoload.php';
  
  $fb = new Facebook\Facebook(['app_id' =&gt; 'XX', 'app_secret' =&gt; 'XX', 'default_graph_version' =&gt; 'v2.5']);
  $helper = $fb -&gt; getRedirectLoginHelper();
  
  try {
  
      try {
          $accessToken = $helper -&gt; getAccessToken();
  
          $isexpired = $accessToken -&gt; isExpired();
          $expiresAt = $accessToken -&gt; getExpiresAt();
  
          echo "AccessToken: ";
          echo $accessToken -&gt; getValue();
  
          echo "&lt;br/&gt;ExpiresAt: ";
          echo $expiresAt;
  
          echo "&lt;br/&gt;IsExpired: ";
          echo $isexpired;
  
          die();
  
      } catch(Facebook\Exceptions\FacebookSDKException $e) {
          // There was an error communicating with Graph
          echo $e -&gt; getMessage();
          exit ;
      }
  } catch(Facebook\Exceptions\FacebookResponseException $e) {
      // When Graph returns an error
      echo 'Graph returned an error: ' . $e -&gt; getMessage();
      exit ;
  } catch(Facebook\Exceptions\FacebookSDKException $e) {
      // When validation fails or other local issues
      echo 'Facebook SDK returned an error: ' . $e -&gt; getMessage();
      exit ;
  } ?&gt;
  </code></pre>
  
  <p>BUT now my problem is, that I DONT get the expiration date as well as the 'isExpired' value, its just empty. The only thing I get is the access token as a string (by 'getValue()').</p>
  
  <p>Can somebody help me? I think my code should be correct? </p>