function w3tc_cdn_google_drive_auth_set()
 {
     // thanks wp core for wp_magic_quotes hell
     $client_id = stripslashes($_POST['client_id']);
     $access_token = stripslashes($_POST['access_token']);
     $refresh_token = stripslashes($_POST['refresh_token']);
     $client = new \W3TCG_Google_Client();
     $client->setClientId($client_id);
     $client->setAccessToken($access_token);
     //
     // get folder details
     //
     $service = new \W3TCG_Google_Service_Drive($client);
     if (empty($_POST['folder'])) {
         $file = new \W3TCG_Google_Service_Drive_DriveFile(array('title' => $_POST['folder_new'], 'mimeType' => 'application/vnd.google-apps.folder'));
         $created_file = $service->files->insert($file);
         $used_folder_id = $created_file->id;
     } else {
         $used_folder_id = $_POST['folder'];
     }
     $permission = new \W3TCG_Google_Service_Drive_Permission();
     $permission->setValue('');
     $permission->setType('anyone');
     $permission->setRole('reader');
     $service->permissions->insert($used_folder_id, $permission);
     $used_folder = $service->files->get($used_folder_id);
     //
     // save new configuration
     //
     delete_transient('w3tc_cdn_google_drive_folder_ids');
     $this->_config->set('cdn.google_drive.client_id', $client_id);
     $this->_config->set('cdn.google_drive.refresh_token', $refresh_token);
     $this->_config->set('cdn.google_drive.folder.id', $used_folder->id);
     $this->_config->set('cdn.google_drive.folder.title', $used_folder->title);
     $this->_config->set('cdn.google_drive.folder.url', $used_folder->webViewLink);
     $this->_config->save();
     $cs = Dispatcher::config_state();
     $cs->set('cdn.google_drive.access_token', $access_token);
     $cs->save();
     wp_redirect('admin.php?page=w3tc_cdn', false);
 }
 private function parent_id_resolve_step($root_id, $folder)
 {
     // decode top folder
     $ids_string = get_transient('w3tc_cdn_google_drive_folder_ids');
     $ids = @unserialize($ids_string);
     if (isset($ids[$root_id . '_' . $folder])) {
         return $ids[$root_id . '_' . $folder];
     }
     // find folder
     $items = $this->_service->files->listFiles(array('q' => '"' . $root_id . '" in parents ' . 'and title = "' . $folder . '" ' . 'and mimeType = "application/vnd.google-apps.folder" ' . 'and trashed = false'));
     if (count($items) > 0) {
         $id = $items[0]->id;
     } else {
         // create folder
         $file = new \W3TCG_Google_Service_Drive_DriveFile(array('title' => $folder, 'mimeType' => 'application/vnd.google-apps.folder'));
         $parent = new \W3TCG_Google_Service_Drive_ParentReference();
         $parent->setId($root_id);
         $file->setParents(array($parent));
         $created_file = $this->_service->files->insert($file);
         $id = $created_file->id;
         $permission = new \W3TCG_Google_Service_Drive_Permission();
         $permission->setValue('');
         $permission->setType('anyone');
         $permission->setRole('reader');
         $this->_service->permissions->insert($id, $permission);
     }
     if (!is_array($ids)) {
         $ids = array();
     }
     $ids[$root_id . '_' . $folder] = $id;
     set_transient('w3tc_cdn_google_drive_folder_ids', serialize($ids));
     return $id;
 }