Saving Google Drive access Tokens for future calls - php

Question

I have a PHP set of scripts using Google's Drive API and PHP examples, but I do not seem to be able to cache authorization requests...
<?php
echo 'This is a new request... setting parameters';
$drive_fileid=$_GET['drive_fileid'];
$drive_userid=$_GET['drive_userid'];
$drive_permission=$_GET['drive_permission'];
$_SESSION['drive_fileid']=$drive_fileid;
$_SESSION['drive_userid']=$drive_userid;
$_SESSION['drive_permission']=$drive_permission;
if($_SESSION['drive_fileid']==''){
echo 'Invalid drive file id. Aborting...';
exit;
} else $drive_fileid=$_SESSION['drive_fileid'];
if($_SESSION['drive_userid']==''){
echo 'Invalid drive user id. Aborting...';
exit;
} else $drive_userid=$_SESSION['drive_userid'];
if($_SESSION['drive_permission']==''){
echo 'Invalid drive permission. Aborting...';
exit;
} else $drive_permission=$_SESSION['drive_permission'];
// Now, if we have been through all this before, lets grab stored tokens...
// These never seem to work.
$getFormSQL="SELECT * from `users` where email='".$email."'";
$getFormData=mysql_query($getFormSQL) or die("Died trying to get auth token from the database with this user");
$formRow = mysql_fetch_array($getFormData);
$oauthToken=$formRow['driveoauth'];
$oauthAccessToken=$formRow['driveoauthaccess'];
require_once 'src/Google_Client.php';
require_once 'src/contrib/Google_DriveService.php';
$client = new Google_Client();
$client->setClientId('myappid.apps.googleusercontent.com');
$client->setClientSecret('myclientsecret');
$client->setRedirectUri('https://www.mywebsite.net/driveapi/oauth2callback');
$client->setScopes(array('https://www.googleapis.com/auth/drive'));
$service = new Google_DriveService($client);
$authUrl = $client->createAuthUrl();
// Since we have no token, we redirect the user to the Google Auth page...
if($oauthToken=='')header( 'Location: '.$authUrl ) ;
$authCode = trim($oauthToken);
// Try authenticate access token
try {
$client->setAccessToken($oauthAccessToken);
$authed=1;
} catch (Exception $e) {
echo '<P>Couldnt authenticate access token';
$authed=0;
}
// If that didn't work, lets generate a new one
if($authed==0){
try {
$accessToken = $client->authenticate($authCode);
$client->setAccessToken($accessToken);
} catch (Exception $e) {
header( 'Location: '.$authUrl ) ;
}
echo 'Got an access token: '.$accessToken;
// Save access token
$accessData=json_decode($accessToken,true);
echo '<P>Extracted and saved: '.$accessData['access_token'].'<P>';
$updateQuery ="UPDATE `users` ";
$updateQuery.=" set ";
$updateQuery.="driveoauthaccess='".$accessData['access_token']."'";
$updateQuery.=" where email='".$email."'";
mysql_query($updateQuery) or die("Unable to update database! ".mysql_error());
}
echo '<P><B>Existing permissions on the file/folder:</B><BR>';
$existingpermissions= $service->permissions->listPermissions($drive_fileid);
$existingpermissionarray=$existingpermissions['items'];
?>
Why am I not able to reuse the tokens I generate?