How to get the email address of the the user currently authenticated user? currently returning null

I would like to see the email and the profile name of the user currently logged in and authenticated in my WebApp.

The backend of my app is in PHP and I am currently using the offical google API PHP client library and gets access to the Google Drive account of the user.

In order to get the name i have been trying to go though the userinfo endpoint.

$service = new Google_Service_Drive($client);
echo(serialize($googleOAuth->userinfo->get()->name) . '   ');

However this is not giving me the users email address its currently returning empty.

These are the authorization scopes i have request of the user:


How do I get the email?

Source: Ask PHP