<?php
class gstorage {
    private $_client;
    private $_storage;
    public function __construct() {
        $scopes = implode(' ', array(
            Google_Service_Storage::DEVSTORAGE_READ_WRITE,
        ));

        $this->_client = new Google_Client();
        $jsonAuth = file_get_contents("<FILENAME TO AUTH.JSON>");
        $this->_client->setAuthConfig(json_decode($jsonAuth, true));
        $this->_client->setScopes($scopes);

        $this->_storage  = new Google_Service_Storage( $this->_client );
    }
?>