Implementing Oauth2 login, Fatal error: Class 'Google_Service' not found

Question

I am updating my website\'s login system from LightOpenID to Google\'s Oauth 2.0.

When I require the Client.php and the Service/Oauth2.php I get an error

Answer 1

After following what Durandal had posted I tried it, but the new path for me is :

require_once 'google-api-php-client/src/Google/autoload.php';

Once I made this changed it worked. Thanks for the help.