I'm wondering how to disable css caching when you use the function drupal_add_css. In hook_preprocess I have some dynamic css loading with this function and by default it generates a cached version of the css file (f.e. style.css?ow65jm) and I couldn't find any information on how to disable this. It gives an issue with some third party applications how rebuild a page view (f.e. Hotjar) who expect a single version of an certain file.

I've checked the performance settings (admin/config/development/performance) and CSS and JS merge/compression is disabled.

Adding the CSS files directly into the tpl files can fixes this but can this also be accomplished with in the preprocess hook and with the drupal_add_css function.

Update - Added template.php and .tpl code:


function mytheme_preprocess(&$vars, $hook) {
if (!(path_is_admin(current_path())) || (arg(0) == 'user' && arg(2) == 'edit')) {
      drupal_add_css('https://fonts.googleapis.com/css?family=Merriweather:700', array('type' => 'external'));
      drupal_add_css( $path_odisee . '/css/normalize.css', array('group' => CSS_THEME, 'every_page' => TRUE, 'weight' => -10));
      drupal_add_css( $path_odisee . '/css/odisee.css', array('group' => CSS_THEME, 'every_page' => TRUE, 'weight' => 0));
      drupal_add_css( $path_odisee . '/css/override.css', array('group' => CSS_THEME, 'every_page' => TRUE, 'weight' => 0));


  <?php print $head; ?>
  <title><?php print $head_title; ?></title>
  <meta name="viewport" content="width=device-width,initial-scale=1">

  <?php print $styles; ?> <!-- here the preprocessed CSS gets loaded -->


Additional information: The people over at Hotjar suggested to keep the cached versions of the css files on the server. Any suggestion on how to force this?

  • Can you provide your current code for drupal_add_css as well as the code that you put in the tpl file?
    – mikeytown2
    Sep 12, 2017 at 16:46
  • I'm still confused as to what you're trying to accomplish. Can you define what you mean when you say "css caching"? Are you using adaptivetheme? I know adaptivetheme will put mutiple css files into $theme_name . '.responsive.styles.css'. From the theme's code: You can disable responsive capability using the theme settings - look under the Global settings.
    – mikeytown2
    Sep 13, 2017 at 16:45
  • The problem is mainly temporary css files which is created (styles.css?ow65jm) every time the cache is cleared a new version of styles.css gets created and the analytics tool (Hotjar) i use can't rebuild the page because of the absence of the file. So there are two options preventing the cached css and force the static file or finding a way to save the 'old' versions of the styles.
    – kim.kaho
    Sep 15, 2017 at 7:22
  • The creation of styles.css is most likely something related to the theme you're using; not apart of Drupal core and thus a lot harder to solve.
    – mikeytown2
    Sep 15, 2017 at 10:09

1 Answer 1


You can try using AdvAgg. Not sure it'll fix your issue because the source of the problem hasn't been identified. https://www.drupal.org/project/advagg

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