How to store google api (OAuth 2) permissions? - authentication

Question

i'm using the examples provided in the "google-api-php-client"-Library (http://code.google.com/p/google-api-php-client/) to implement user login and authorization on my website with google services.
I didn't make any changes to the examples, except adding my Client-ID, etc..
The authorization itself works fine: Users can login and i can fetch the provided informations.
However, when leaving the page, the whole authorization procedure is called again; users are not remembered and need to grant permissions again, which is some kind of annoying and not typical for google-logins as i know them.
For example: On stackoverflow, i'm logged in with my google account.
Whenever i revisit this site, i'm logged in automaticly, or (if logged out) just have to log in again - i do not have to confirm the general rights again.
Using the examples on my site however, forces the user to allow access whenever the site is visited again.
Did i make any mistakes, when using the examples?
What do i have to do, to avoid the permission request over and over again?
Thanks in advance for any kind of help!

Answer 1

Use this code for first time to retrieve access_code and save it to database:
<?php
require 'google-api-php-client/src/Google_Client.php';
require 'google-api-php-client/src/contrib/Google_DriveService.php';
require 'google-api-php-client/src/contrib/Google_Oauth2Service.php';
session_start();
$client = new Google_Client();
$client->setClientId(CLIENT_ID);
$client->setClientSecret(CLIENT_SECRET);
$client->setRedirectUri(REDIRECT_URI);
$client->setScopes(array(
'https://www.googleapis.com/auth/drive',
'https://www.googleapis.com/auth/userinfo.email',
'https://www.googleapis.com/auth/userinfo.profile'));
$client->setUseObjects(true);
$service = new Google_DriveService($client);
$client->authenticate();
$_SESSION['token'] = $client->getAccessToken();
const ACCESS_TOKEN=$_SESSION['token'];
//code here to save in database
?>
Once ACCESS_TOKEN is saved in database change code to:
<?php
require 'google-api-php-client/src/Google_Client.php';
require 'google-api-php-client/src/contrib/Google_DriveService.php';
require 'google-api-php-client/src/contrib/Google_Oauth2Service.php';
session_start();
$client = new Google_Client();
$client->setClientId(CLIENT_ID);
$client->setClientSecret(CLIENT_SECRET);
$client->setRedirectUri(REDIRECT_URI);
$client->setScopes(array(
'https://www.googleapis.com/auth/drive',
'https://www.googleapis.com/auth/userinfo.email',
'https://www.googleapis.com/auth/userinfo.profile'));
$client->setUseObjects(true);
$service = new Google_DriveService($client);
//ACCESS_TOKEN is already saved in database, is being saved on first time login.
$_SESSION['access_token'] = ACCESS_TOKEN;
if (isset($_SESSION['access_token'])) {
$client->setAccessToken($_SESSION['access_token']);
}
if ($client->getAccessToken())
{
$userinfo = $service->about->get();
echo '<script>console.log('.json_encode($userinfo).');</script>';
$userinfoService = new Google_OAuth2Service($client);
$user = $userinfoService->userinfo->get();
echo '<script>console.log('.json_encode($user).');</script>';
}
?>

Answer 2

That works fine for me.
Based on the kaushal's answer:
<?php
require_once 'globals.php';
require_once 'google-api-php-client/src/Google_Client.php';
require_once 'google-api-php-client/src/contrib/Google_DriveService.php';
$client = new Google_Client();
// Get your credentials from the APIs Console
$client->setClientId('YOUR_ID');
$client->setClientSecret('YOUR_SECRET');
$client->setRedirectUri('REDIRECT_URI');
$client->setScopes(array('https://www.googleapis.com/auth/drive'));
$service = new Google_DriveService($client);
$client->setUseObjects(true);
//if no token in the session
if ($_SESSION['google_token'] == '') {
//get stored token from DB
$sToken = $oDb->getOne("SELECT `google_token` FROM `users` WHERE `u_id` = " . (int)$_SESSION['user_id']);
//if no stored token in DB
if ($sToken == '') {
//autentificate user
$client->authenticate();
//get new token
$token = $client->getAccessToken();
//set token in session
$_SESSION['google_token'] = $token;
// set token in DB
$oDb->Query("UPDATE `users` SET `google_token`='$token' WHERE `u_id` = " . (int)$_SESSION['user_id']);
} else {
$_SESSION['google_token'] = $sToken;
}
}
$client->setAccessToken($_SESSION['google_token']);
//do what you wanna do with clients drive here
?>

Answer 3

The Google Drive SDK documentation includes a complete PHP sample application that you can use as a reference to get started:
https://developers.google.com/drive/examples/php
Basically, once the user is logged in and you retrieve access token and refresh token, you store those credentials in a database and reuse them instead of asking the user to authenticate every time.