【Drupal 8】依據使用者的不同在body上面增加Class

function YOU_THEME_NAME_preprocess_html(&$variables)
{
    // The getRoles() method will return us the machine names, so there is no
    // need to process roles names additionally. However, I suggest prefixing
    // the names with "role-", so it's more obvious.
    
    foreach ($variables['user']->getRoles() as $role) {
        $variables['attributes']['class'][] = 'role-' . $role;
    }
}