oauth2 access token expire - php

Question

<?php
session_start();
require_once realpath(dirname(__FILE__) . '/Google/src/Google/autoload.php');
/************************************************
ATTENTION: Fill in these values! Make sure
the redirect URI is to this page, e.g:
http://localhost:8080/user-example.php
************************************************/
$client_id = 'xxxxx-1l76cd2vi4ik5oqm5s20nj965riu4hum.apps.googleusercontent.com';
$client_secret = 'secret';
$redirect_uri = 'http://www.audit.polydevs.co.uk/oauth2callback.php?login';
$client = new Google_Client();
$client->setClientId($client_id);
$client->setClientSecret($client_secret);
$client->setRedirectUri($redirect_uri);
$client->setScopes('email');
/************************************************
If we're logging out we just need to clear our
local access token in this case
************************************************/
if (isset($_REQUEST['logout'])) {
unset($_SESSION['access_token']);
header("Location: login.php");
}
if (isset($_REQUEST['logoutInvalid'])) {
unset($_SESSION['access_token']);
header("Location: login.php?invalid");
}
/************************************************
If we have a code back from the OAuth 2.0 flow,
we need to exchange that with the authenticate()
function. We store the resultant access token
bundle in the session, and redirect to ourself.
************************************************/
if (isset($_GET['code'])) {
$client->authenticate($_GET['code']);
$_SESSION['access_token'] = $client->getAccessToken();
$redirect = 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF'];
header('Location: ' . filter_var($redirect, FILTER_SANITIZE_URL));
}
/************************************************
If we have an access token, we can make
requests, else we generate an authentication URL.
************************************************/
if (isset($_SESSION['access_token']) && $_SESSION['access_token']) {
$client->setAccessToken($_SESSION['access_token']);
} else {
$authUrl = $client->createAuthUrl();
}
/************************************************
If we're signed in we can go ahead and retrieve
the ID token, which is part of the bundle of
data that is exchange in the authenticate step
- we only need to do a network call if we have
to retrieve the Google certificate to verify it,
and that can be cached.
************************************************/
if ($client->getAccessToken()) {
$_SESSION['access_token'] = $client->getAccessToken();
$token_data = $client->verifyIdToken()->getAttributes();
}
if($client->isAccessTokenExpired()) {
echo 'Access Token Expired'; // Debug
$client->authenticate;
$newAccessToken = json_decode($client->getAccessToken());
$client->refreshToken($newAccessToken->refresh_token);
}
if (strpos($client_id, "googleusercontent") == false) {
echo missingClientSecretsWarning();
exit;
}
if (isset($_REQUEST['login'])) {
if (isset($authUrl)) {
header('Location:'.$authUrl);
} else {
require_once('func/connect.php');
$query = "SELECT * FROM users WHERE email = ?";
$stmt = $db->prepare($query);
$stmt->bindValue(1, $token_data['payload']['email']);
$stmt->execute();
$count = $stmt->rowCount();
if ($count > 0) {
header('Location: index.php');
} else {
$plus = new Google_Service_Plus( $client );
$me = $plus->people->get('me');
$query = "INSERT INTO users (name,email,role) VALUES(?,?,?)";
$stmt = $db->prepare($query);
$stmt->bindValue(1, $me['displayName']);
$stmt->bindValue(2, $token_data['payload']['email']);
$stmt->bindValue(3, 'regular');
$stmt->execute();
header('Location: index.php');
}
}
}
Specifically here
if($client->isAccessTokenExpired()) {
echo 'Access Token Expired'; // Debug
$client->authenticate;
$newAccessToken = json_decode($client->getAccessToken());
$client->refreshToken($newAccessToken->refresh_token);
}
Once my token expires, I cannot logout nor access any of the webpages as they require to have a valid token..
nor can i login, as that requires it too!
Or alternatively, can I just disable it!
EDIT
I'm very sorry, I'm tired and assuming everyone knows what I'm talking about.. The issue is that when the access token expires, I can either unset the $_SESSION['access_token'] and force relogging in ( major problem ) or have a way of just refreshing / disabling the token/expire so it won't impede on any ongoing processes for the user.

Answer 1

I would recommend reading a basic guide about OAuth so you can get the general idea.
Basically the server and the client go through a series of steps to prove that they are who they say they are. Once this has been completed the server will issue a short lived access_token and a refresh_token.
You can then use this access_token in all Api requests. However this access_token has a limited lifetime. When it expires you must give the refresh_token to the server and it will issue another access_token
To do this with the Google Api PHP library you use this code
//$client is the GApi Client
if($client->isAccessTokenExpired()) {
echo 'Access Token Expired'; // Debug
$client->refreshToken('your_refresh_token');
}