PHP Notice

Hello
I have a php notice :
[07-Jul-2017 14:20:00 UTC] PHP Notice: Undefined index: HTTP_HOST in wp-content/plugins/custom-content-shortcode/includes/modules/url.php on line 44

static function init() {

global $wp;

// Get routes
self::$route = $wp->request;
self::$routes = explode(‘/’, self::$route);

// Get queries: direct method
$request_url = untrailingslashit( ‘http://’ . $_SERVER[‘HTTP_HOST’] . $_SERVER[‘REQUEST_URI’] );

https://stackoverflow.com/questions/12347048/undefined-index-http-host-even-though-it-is-checked

You need test $_SERVER[‘HTTP_HOST’] is set before use it

regards