How to tell Drupal to look for templates in module directory?

Question

I'd like to provide template implementation in my module and allow themes to override it. Basically, I add a suggestion by this simplified code:

function attach_preprocess_node(&$vars) {
  $vars['theme_hook_suggestions'][] = 'node__test';
}

(I don't want to use hook_theme to add a new theme because I want to reuse preprocess node functions. The theme name are awkward but I don't want to write node_attach_% to avoid confusion with node type.)

Then I use hook_theme_registry_alter() to add module path:

function attach_theme_registry_alter(&$theme_registry) {
  $path = drupal_get_path('module', 'attach') . '/themes';
  $theme_registry_copy = $theme_registry;
  _theme_process_registry($theme_registry_copy, 'phptemplate', 'theme_engine', 'node', drupal_get_path('module', 'node'));
  $theme_registry += array_diff_key($theme_registry_copy, $theme_registry);
  if (!isset($theme_registry['node']['theme paths'])) {
    $theme_registry['node']['theme paths'] = array();
  }
  if (!isset($theme_registry['node']['theme paths'])) {
    $first_element = array_shift($theme_registry['node']['theme paths']);
    if ($first_element) {
      array_unshift($theme_registry['node']['theme paths'], $first_element, $path);
    }
    else {
      array_unshift($theme_registry['node']['theme paths'], $path);
    }
  }
}

However it does not work. That means: the file themes/node--super.tpl.php is not used. It is used only if I copied it to the theme folder.

Answer 1

Basically you can save yourself a bit of headache by implementing hook_theme() instead of altering the registry.

I suggest a look at theming_example in the Examples project, handily reproduced on this API doc page, perhaps with especially helpful code on this page.

function theming_example_list_page() {
  $items = array(
    t('First item'),
    t('Second item'),
    t('Third item'),
    t('Fourth item'),
  );

  // First we'll create a render array that simply uses theme_item_list.
  $title = t("A list returned to be rendered using theme('item_list')");
  $build['render_version'] = array(
    // We use #theme here instead of #theme_wrappers because theme_item_list()
    // is the classic type of theme function that does not just assume a
    // render array, but instead has its own properties (#type, #title, #items).
    '#theme' => 'item_list',
    // '#type' => 'ul',  // The default type is 'ul'
    // We can easily make sure that a css or js file is present using #attached. 
    '#attached' => array('css' => array(drupal_get_path('module', 'theming_example') . '/theming_example.css')), 
    '#title' => $title, 
    '#items' => $items, 
    '#attributes' => array('class' => array('render-version-list')),
  );

  // Now we'll create a render array which uses our own list formatter,
  // theme('theming_example_list').
  $title = t("The same list rendered by theme('theming_example_list')");
  $build['our_theme_function'] = array(
    '#theme' => 'theming_example_list', 
    '#attached' => array('css' => array(drupal_get_path('module', 'theming_example') . '/theming_example.css')), 
    '#title' => $title, 
    '#items' => $items,
  );
  return $build;
}

This is all for Drupal 7.

Answer 2

Maybe this one works:

/**
 * Implements hook_theme().
 */
function MODULE_theme($existing, $type, $theme, $path) {
  return array (
    'node__CONTENTTYPE' => array (
      'variables' => array( . . . ),
      'template' => 'node--CONTENTTYPE' ,
      'base hook' => 'node',
      'path' => drupal_get_path('module', 'MODULE'),
    ),
  );
}

Important here is the key 'base hook'.

Answer 3

I like dashohoxha's solution of the hook_theme implementation but was not able to get it working. After some more googling I found a variation that worked nice for me:

/**
 * Implements hook_theme().
 */
function mymodule_theme($existing, $type, $theme, $path) {
  $theme = array();
  $theme['node__blog_post'] = array(
    'render element' => 'content',
    'base hook' => 'node',
    'template' => 'node--blog_post',
    'path' => drupal_get_path('module', 'mymodule') . '/templates',
   );
  return $theme;
}

Notes: my custom module is called 'mymodule' and my custom content type is called 'blog_post'. The tpl.php that I use is called 'node--blog_post.tpl.php' and it is located in the 'templates' sub folder of my module.

Answer 4

Here is my snippet to declare views templates stored in the "template" folder of my "custom_module":

/**
 * Implements hook_theme_registry_alter().
 */
function custom_module_theme_registry_alter(&$theme_registry) {
  $extension   = '.tpl.php';
  $module_path = drupal_get_path('module', 'custom_module');
  $files       = file_scan_directory($module_path . '/templates', '/' . preg_quote($extension) . '$/');

  foreach ($files as $file) {
    $template = drupal_basename($file->filename, $extension);
    $theme    = str_replace('-', '_', $template);
    list($base_theme, $specific) = explode('__', $theme, 2);

    // Don't override base theme.
    if (!empty($specific) && isset($theme_registry[$base_theme])) {
      $theme_info = array(
        'template'   => $template,
        'path'       => drupal_dirname($file->uri),
        'variables'  => $theme_registry[$base_theme]['variables'],
        'base hook'  => $base_theme,
        // Other available value: theme_engine.
        'type'       => 'module',
        'theme path' => $module_path,
      );

      $theme_registry[$theme] = $theme_info;
    }
  }
}

Hope it helps someone.

Answer 5

I asked this once on Stack Overflow. Basically, you have to implement hook_theme_registry_alter() to get your path added to the theme hook template path; then, on hook_enable(), you call drupal_theme_rebuild() to clear the theme registry cache and get your path scanned for templates.