Member ID tracking and cookies ID

CMS & WordPress
1

I have set it up a member ID tracking.$project_vars[‘session_name’] = “Dvigala_com_member”;

An example:

ob_start();

if(isset($project_vars['session_name']) && $project_vars['session_name']!="")
session_name($project_vars['session_name']);
session_start();

  $cookie_exp_time = time() + (60 * 60 * 24 * 15); // 15 days
    $cookie_name = $project_vars['session_name'] . "-uniq-id";
    if (isset($_COOKIE[$cookie_name])) {
        $cookie_id = $_COOKIE[$cookie_name];
    } else {
        $cookie_id = session_id();
    }
    setcookie($cookie_name, $cookie_id, $cookie_exp_time);

$project_vars['session_name'] = "Domain_net_member";

Can be improved ID tracking inside WordPress and placed programming code inside functions child theme as PHP?

2

Potentially undefined variable $project_vars.
Potentially undefined key ‘session_name’.