Add body classes to 404 and 403 error pages

Question

I need to add a body class to the page when either a 403 or 404 error is served, I'm not sure how to go about this. I'm using logintoboggan which sets the default 403 page to toboggan/denied so don't want to override that and break functionality.

Any pointers would be great.

Answer 1

You can implement hook_preprocess_page(), and alter the value of $variables['body_classes'], which contains a list of CSS classes separated with a comma.
In Drupal 6, code similar to the following one should work:

function mymodule_preprocess_page(&$variables) {
  $headers = drupal_get_headers();

  if (preg_match('@HTTP/1\.[01]\x20+403@', $headers)) {
    $variables['body_classes'] .= 'error-403,';
  }
  elseif (preg_match('@HTTP/1\.[01]\x20+404@', $headers)) {
    $variables['body_classes'] .= 'error-404,';
  }  
}

Replace "error-403" and "error-404" with the actual CSS classes you want to use.

This is similar to the code I have used in a module hosted on Drupal.org, which had to detect when Drupal 6 shown an "access denied" page, or a "page not found" page.

Answer 2

For anyone working with Drupal 7, the function names and the way you pass variables are a bit different. The D7 solution for a 404 would look like this:

function MYMODULE_preprocess_html(&$variables) {
  $headers = drupal_get_http_header();

  if (isset($headers['status']) && $headers['status'] == '404 Not Found') {
    $variables['classes_array'][] = 'page-404';
  }
}

The drupal_get_headers() function from D6 is now drupal_get_http_header() in D7. The values returned are structured a bit differently. You can view the contents of the array with "dpm($headers);" if you're using the devel module.

Finally, additional class variables can be added as elements of the $variables['classes_array'] by assigning them to an empty index, which will then be added to the html body tag via the template_process() function.

Answer 3

I've created a custom module in order to have a custom twig template for my 404 error page.

I needed to have a custom body class for this page for theming purpose.

Here is what I've done :

function MYTHEME_preprocess_html(&$variables) {

    // Check if current request is an exception to get error type
    $status = \Drupal::requestStack()->getCurrentRequest()->attributes->get('exception');

    // add body classes.
    if ($status && $status->getStatusCode() == 404) {
        $variables['attributes']['class'][] = 'path-error-404';
    }

    if ($status && $status->getStatusCode() == 403) {
        $variables['attributes']['class'][] = 'path-error-404';
    }

}