Use THEME_preprocess_page() to add a "subsection" body class.
The Zen Theme for Drupal is a great place to start building a standards-compliant Drupal site. One of the useful features of Zen for site design is the fact that it adds multiple classes to the document body (in addition to the classes already added by Drupal core). But if these classes are not enough, we can easily add more through THEME_preprocess_page().
By default, Zen uses the URL path to create "section" and "page" classes which are added as to the body tag. Take for example, the hypothetical page: site.com/spectrum/red the body tag would include the classes:
- page-spectrum-red
- section-spectrum
In most cases this is sufficient to craft CSS selectors to style a specific page, or collection of pages within a section. However, what about the case where content is buried deeper? For example, imagine these urls:
- site.com/spectrum/visible/orange
- site.com/spectrum/visible/yellow
- site.com/spectrum/ultraviolet/90nm
It would be nice to be able to able to add a selector to style all of the pages in the "visible" subsection differently than those in the "ultraviolet" subsection. Lets imagine that for site.com/spectrum/visible/orange, the the following selectors were available to us:
- page-spectrum-orange
- section-spectrum
- subsection-visible
We can do this by implementing hook_preprocess_page() in template.php, with the following (where THEME is the id of our theme):
<?php
/**
* Override or insert variables into the page templates.
*
* NRD: Output body a body class based on the "subsection" which works
* much like the default Zen "section" body class.
* E.g.: /section0/subsection1/page2 =>
* section-section0
* subsection-subsection1
*
* @param $vars
* An array of variables to pass to the theme template.
* @param $hook
* The name of the template being rendered ("page" in this case.)
*/
function zen_THEME_preprocess_page(&$vars, $hook) {
// Add unique class for each subsection (e.g. /section0/subsection1/page2
$path = drupal_get_path_alias($_GET['q']);
$sections = explode('/', $path,3);
// If subsection *and* page are defined
if ($sections[1] && $sections[2]) {
$classes[] = zen_id_safe('subsection-' . $sections[1]);
}
// Add classes to body
$vars['body_classes_array'] = $classes;
$vars['body_classes'] = implode(' ', $classes); // Concatenate with spaces.
}
?>Now we can select and style all pages in the "visible" subsection with a CSS selector such as:
body.subsection-visible #somecontainer {
background-color: #f0f0f0;
}
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Comments
#1 Without Zen?
Submitted by Andre M. (not verified) on Wed, 03/24/2010 - 10:05.
Since I developed my own theme, is it possible to do this without the use of zen theme?
#2 Zen not required...
Submitted by Eric Weik on Wed, 03/24/2010 - 11:24.
Hi Andre,
Yes, you can implement this in any theme. Add the
function THEME_preprocess_page(&$vars, $hook) {} code from my example to your template.php (replacing THEME with your theme name). It calls a Zen theme function called zen_id_safe(), so you'll need to implement this in your theme as provided by the Zen theme (it just makes sure that the id output conforms to W3C specifications for ID attributes).
If I were you, I would download the Zen theme and open up zen/zen/template.php, and simply copy and paste the zen_id_safe function declaration into your theme's template.php. While it is open, poke around and see how the Zen theme does things. Even when I am doing theme development "from scratch", I often pull in parts of the Zen theme as recipes. It does a number of useful things.
Or if you want, you can just copy and paste from here:
<?php/**
* Converts a string to a suitable html ID attribute.
*
* <a href="http://www.w3.org/TR/html4/struct/global.html#h-7.5.2" title="http://www.w3.org/TR/html4/struct/global.html#h-7.5.2">http://www.w3.org/TR/html4/struct/global.html#h-7.5.2</a> specifies what makes a
* valid ID attribute in HTML. This function:
*
* - Ensure an ID starts with an alpha character by optionally adding an 'id'.
* - Replaces any character except alphanumeric characters with dashes.
* - Converts entire string to lowercase.
*
* @param $string
* The string
* @return
* The converted string
*/
function zen_id_safe($string) {
// Replace with dashes anything that isn't A-Z, numbers, dashes, or underscores.
return strtolower(preg_replace('/[^a-zA-Z0-9-]+/', '-', $string));
}
?>
I hope this helps! -Eric
#3 The urls
Submitted by Andre M. (not verified) on Fri, 03/26/2010 - 14:34.
Hi Eric
Thanks for replying... How unfortunate I cannot test this, since the server I was working on is down at the moment... :( As soon as it becomes online I will try and post here.
Thank you,
Andre M.
#4 Some problem
Submitted by Andre M. (not verified) on Mon, 03/29/2010 - 11:05.
Hi Eric
I put the mytheme_id_safe function first. Then, below it, I put the mytheme_preprocess_page function. I also added the following code into page.tpl.php:
<?php echo $body_classes; ?>However, Drupal didn't add any class or id (with subsection-) in body. Also, in admin page, I have the following warning:
warning: implode() [function.implode]: Bad arguments. in /path-to/mytheme/template.php on line 457.Referring to the following line:
$vars['body_classes'] = implode(' ', $classes);I must have done something wrong...
Thanks,
Andre
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