Add body class depending on current URL
I found a solution, I wrote this in a preprocess function:

function THEME_preprocess_html(&amp;$vars) {
  // Add body class if current url is configured to have header/footer hidden.
  $urls_to_test = array(
    $_GET['q'],
    drupal_get_path_alias($_GET['q']),
  );
  foreach (explode("\n", theme_get_setting('head_footer_hiding_urls')) as $url) {
    if (in_array($url, $urls_to_test)) {
      $vars['classes_array'][] = 'theme-hide-header-footer';
    }
  }
}