template.php

Note: It's worth reading through the comments on this post, this technique isn't as useful as it first appears - Dale, Feb 18/09

The addition of preprocessor functions to Drupal 6 makes customizing template variables straightforward and clean (bravo to everyone who made this happen!). Have you ever wondered where the variables come from? It's actually helpful knowing, even if you're a themer with basic PHP knowledge.

Some reasons why:

Need to know absolutely, positively, and without-a-doubt what theming variables are available to your template? Here's a trick for total visibility.

In my previous post, Take Control of Your PHPTemplate Variables, I described the _phptemplate_variables function in template.php. It's passed a parameter named $vars which is an associative array of all the variables that will be created in the template . . . which is exactly what we're looking for!

Since _phptemplate_variables allows us to create theme variables, we have a simple way to get the $vars data into the template where we can look at it. Just put the following code in your template.php file:

function _phptemplate_variables($hook, $vars) {
  return array('vars_data' => $vars);
}

And the following code in your template file:

For your templating pleasure Drupal's PHPTemplate engine makes available a cast of variables, including such favourites as $title, $content, and $node. Modules also contribute: CCK adds CCK specific template variables as well as fields to the node object, and the comments module adds an entry to the $links variable. But what happens when something isn't formatted the way you or your customer wants, or you have a project specific variable you want to add?

Introducing the _phptemplate_variables function!

The _phptemplate_variables function lives in your theme's template.php file and is called by the PHPTemplate engine after the various modules have done their thing, and before PHPTemplate actually renders your node into HTML. _phptemplate_variables provides a single, common location to all .tpl.php files for adding or changing variables.