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This chapter is from the book

Alias: Page

Do you remember the TV show Alias? It was full of wigs and disguises and trickery and deception and intrigue! URL aliases are a bit like throwing a wig onto a system path—they change the way the path looks, but keep the content the same. If you want your site to use URLs that are more closely tied to page content than node/2868, you will need to use the module Path to create URL aliases. The bad news is that Drupal’s theming system cannot recognize the URL aliases that you have created with the wigs and the dark sunglasses. Instead, you must explicitly show Drupal how you want to convert these URLs into a template suggestion. In the next section, you will learn how to further customize this process to create template suggestions for each category.

The first step in this process is to grab the URL and examine its components before the page template is processed. Using the URL alias, you will compile a new list of suggested page templates. Being careful to match the alias for the page you want to redesign, you then add a new template file to your theme. Now when Drupal looks for the best match for its page template, it will use your new list of suggested file names and find the new page template.

New Templates from Aliased URLs

The work of compiling the new list of suggested templates happens in the page preprocess function in your theme’s template.php file. If you have already created a preprocess_page function in your theme’s template.php file, you may add this snippet to either the beginning or the end of the function. If you do not already have this function, you will need to include the very first (and very last) lines of this snippet in your theme’s template.php file.

It takes several steps to compile a new list of suggested templates for the URL alias of your page:

  1. Confirm that the module path is enabled. Without this module, your site will not have URL aliases and this function will be irrelevant.
  2. By default, Drupal allows you to access the system path, but not the URL alias. You need to use a special decoder ring, drupal_get_path_alias, to convert the system path back to its URL alias.
  3. Break the URL alias into its components using PHP function explode. You will use these components to build the new page template file name.
  4. Make sure your Web page is not an editing page. If it is, Drupal’s templates can be used and this function becomes irrelevant.
  5. Create a variable to hold the new template suggestions, and establish the base word for the new template’s file names. You could use any word here, but using the base word “page” allows you to keep all page templates together. For example, page-your-custom-url.tpl.php would be alphabetically close to page-front.tpl.php.
  6. Loop through each part of the URL and build new template suggestions. This mimics the way Drupal offers its templates. For example, if your URL alias is books/fiction/story-about-ping, you will now be able to create three new page templates: page-books.tpl.php, page-books-fiction.tpl.php, and page-books-fiction-story-about-ping.tpl.php.
  7. Add the new template suggestion to a list that will be handed back to Drupal.
  8. Finally, return the list of suggested template names back to Drupal.

In your file template.php, the PHP snippet for these eight steps is as follows:

function bolg_preprocess_page(&$variables) {
// Step 1:
if (module_exists('path')) {


// Step 2:
$path_alias = drupal_get_path_alias($_GET['q']);


// Step 3:
$alias_parts = explode('/', $path_alias);


// Step 4:
$last = array_reverse($alias_parts);
$last_part = $last[0];
if ($last_part != "edit") {


// Step 5:
  $templates = array();
  $template_name = "page";


// Step 6:
  foreach ($alias_parts as $part) {
    $template_name = $template_name . '-' . $part;


// Step 7:
    $templates[] = $template_name;
  }


// Step 8:
  $variables['template_files'] = $templates;


} // End of the edit check
} // End of the check for the path module
} // End of the preprocess_page function

After you place this snippet in your theme’s template.php file, you may use any part of the URL alias as a page template name. Note, however, that you must refresh the theme registry before Drupal sees your new template suggestions.

Page Templates for Views

The Views module is very clever. When you provide a URL alias for your page view, it automatically performs its version of the function that was described in the previous section. For example, if you have a view with the URL alias recent/screencasts, the Views module will automatically generate the following page template suggestions: page-recent.tpl.php and page-recent-screencasts.tpl.php. The default page template, page.tpl.php, will be used there if none of these files exist within the theme’s directory.

Adding CSS Classes

The Zen theme allows designers to adapt their layout based on the classes that are applied to the body. You can add this level of customization to your theme as well. To add classes to your page, you will need to alter the contents of the page variable $body_classes. This variable contains a list of classes all separated by a space. To add new classes to this variable, you can use the same function that was described previously in this chapter. In the code outlined in the section “New Templates from Aliased URLs,” replace step 8 with the following lines (the first line is a comment, not part of the functioning code):

// Step 8:
$classes = implode(' page-', $templates);
$variables['body_classes'] = $variables['body_classes'] . ' $classes';

This will add your new body classes to the end of the list of default classes.

Page Templates for Content Types

If necessary, you can change the way a node is displayed within a page with Drupal’s node templates. If you knew that one of your content types needed a different page layout, however, you could assign a new page template to that content type. This process is almost the same as that followed in the previous examples.

To make a content type-specific page template, you will need to know which type of content you are looking at. The only time you can know this with certainty is when you are looking at a page that contains only one node. This page would normally use the page template page-node.tpl.php.

To create a template suggestion based on content type, you will need to replace steps 6, 7, and 8 of the preprocess function described in the section “New Templates from Aliased URLs” with the following snippet. Notice the use of arg() in this example; arg() is a special variable that grabs individual parameters from the system path for the displayed page. For example, the value of arg(0) for node/2868 is “node” and the value of arg(1) is 2868.

if (arg(0) == "node" && is_numeric(arg(1))) {
   $node_type = $variables['node']->type;
   $variables['template_files'] = "$template_name-node-$node_type.tpl.php";
}

If you want to make templates for both URL aliases and content types, you can add this snippet after step 8 in the code snippet described in “New Templates from Aliased URLs:”

if (arg(0) == "node" && is_numeric(arg(1))) {
   $node_type = $variables['node']->type;
   array_push($variables['template_files'], "$template_name-node-$node_type.tpl.php");
}

The examples in this section should give you a solid toolkit for creating unique page templates. You may think of even more ways to customize your templates, too!

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