Google Drive Api intergration with php - php

Question

I want to show my google drive into website. Which means if anybody use my website can see google drive files and folder without login. Here is some code which i am trying to implement.
include_once 'google-api-php-client/src/Google/autoload.php';
$scopes = array( 'https://www.googleapis.com/auth/drive','https://www.googleapis.com/auth/drive.appdata',
'https://www.googleapis.com/auth/drive.file','https://www.googleapis.com/auth/drive.metadata','https://www.googleapis.com/auth/drive.metadata.readonly','https://www.googleapis.com/auth/drive.photos.readonly','https://www.googleapis.com/auth/drive.readonly');
/**
* Create AssertionCredentails object for use with Google_Client
*/
$creds = new Google_Auth_AssertionCredentials(
$serviceAccountName,
$scopes,
file_get_contents($keyFile)
);
$creds->sub = $delegatedAdmin;
/**
* Create Google_Client for making API calls with
*/
$client = new Google_Client();
$client->setApplicationName($appName);
$client->setClientId($clientId);
$client->setAssertionCredentials($creds);
/**
* Get an instance of the Directory object for making Directory API related calls
*/
$service = new Google_Service_Drive($client);
$optParams = array(
'pageSize' => 10,
'fields' => "nextPageToken, files(id, name)"
);
$results = $service->files->listFiles($optParams);
print_r($results); exit;
/**
Can anybody tel me how to achieve this. I am getting this error
Fatal error: Uncaught exception 'Google_Auth_Exception' with message 'Error refreshing the OAuth2 token, message: '{ "error" : "unauthorized_client", "error_description" : "Unauthorized client or scope in request." }

Answer 1

You need to add
if ($client->getAuth()->isAccessTokenExpired()) {
$client->getAuth()->refreshTokenWithAssertion();
}
after
$client->setAssertionCredentials($creds);