Question

I’m developing using the Facebook PHP SDK.

I wanted to make it so that when the user logs out of Facebook, they will automatically be logged out of my website too.

I am using the following code to detect the session, using the session cookie:

$facebook->getUser();

For some reason, the getUser() function still returns the user’s Facebook ID, even after they have logged out of Facebook on their website.

Am I to detect the session first using another Function?

On the official documentation example here, is the following excerpt from their comments:

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

// We may or may not have this data based on whether the user is logged in.
//
// If we have a $user id here, it means we know the user is logged into
// Facebook, but we don't know if the access token is valid. An access
// token is invalid if the user logged out of Facebook.

This lead me to believe that the session cookie for Facebook would become unset upon Facebook logout?

Kind Regards,

Luke

Answer 1

I have the same issue!

The FB PHP SDK saves those things into the $_SESSION!
You can delete them like this when your user clicks logout:

$_SESSION['fb_'.APP_ID.'_user_id'] = '';
$_SESSION['fb_'.APP_ID.'_access_token'] = '';

Although this is not the final solution, it works for now.

I appreciate comments and solutions on that!