I got it all working on one server of mine. Now I want to do the same on a customers server, but it works until after I accept the stuff at https://accounts.google.com/o/oauth2/auth. Then I return to my login_with_google.php page and the page stays empty with an URL like:
Manuel Lemos - 2014-11-07 00:13:57 - In reply to message 1 from snader
It is hard to tell without seeing your customer server.
If you are using the OAuth class, keep in mind that by default it uses session variables to store protocol state data, so make sure that sessions are working on your customer server.
In an case, blank pages pages may be sign of fatal PHP errors. Check in your browser developer tools if it is returning HTTP status 500. Also make sure PHP error log is really enabled and the Web server is restarted after changing PHP options, as new options may not be read until the server is restarted.