PHP Undefined index: HTTP_USER_AGENT

Question

The following code validates the user agent accessing the site however I am getting the error. What do I need to update to accommodate scenarios where there is no user agent

Answer 1

use isset:

if( !isset( $_SERVER['HTTP_USER_AGENT'])){
    $name = "none";
}else{
     $userAgent = strtolower($_SERVER['HTTP_USER_AGENT']);

    if (preg_match('/opera/', $userAgent)) {
        $name = 'opera';
    } [... yourcode ...]
}