Providing Placeholder Tokens for Drupal 7

The first of two steps required to add new tokens to Drupal 7 is implementing hook_token_info() in order to give Drupal a list of the placeholders your module provides. Placeholders can be grouped together by creating a new token type and placing new tokens under that grouping or by adding new tokens to an existing token type provided by another module like the node module. Token types can be defined as global meaning their value can be calculated without any additional context, or as 'needs-data' tokens that require additional information about the context in which they are being used in order to calculate their value. For example, a [node:title] token needs to know which node is being referenced, whereas a [system:date] token doesn't need any additional reference to calculate the current date. In this lesson we will be adding the following token types:

• [databasics-totals] - For tokens that can be calculated without any additional context.
• [databasics-page] - For tokens that require additional context in order to be rendered. In this case, they need to know which page is currently being viewed and are thus only useful in the context of viewing a page.

And these tokens:

• [databasics-totals:count] - Total page views for the entire site.
• [databasics-page:view-count] - Number of times the current page has been viewed by the current user..
• [databasics-page:last-viewed] - Date the current page was last viewed..

We use hook_token_info() to provide Drupal with information about available placeholder tokens and their types. Here's an example hook_token_info() implementation:

/**
 * Implements hook_token_info().
 */
function databasics_token_info() {
  $info = array();

  $info['types'] = array(
    'databasics-totals' => array(
      'name' => t('Databasics totals'),
      'description' => t('Global databasics tokens.'),
    ),
    // [databasics-page:]
    'databasics-page' => array(
      'name' => t('Databasics'),
      'description' => t('Tokens for databasics page counts.'),
      'needs-data' => array('databasics_record'),
    ),
  );

  $info['tokens'] = array(
    'databasics-totals' => array(
      // [databasics-totals:count]
      'count' => array(
        'name' => t('Total page views'),
        'description' => t('Total page views for entire site.'),
      ),
    ),
    // Page specific tokens.
    'databasics-page' => array(
      // Add a token for the view count.
      // [databasics-page:view-count]
      'view-count' => array(
        'name' => t('View count'),
        'description' => t('Number of times the page has been viewed by the current user.'),
      ),
      // [databasics-page:last-viewed]
      'last-viewed' => array(
        'name' => t('Last viewed'),
        'description' => t('Date the page was last viewed.'),
      ),
    ),
  );

  // [node:view-count], [node:view-count:last-viewed]
  $info['tokens']['node'] = array(
    'view-count' => array(
      'name' => t('View count'),
      'description' => t('Number of times the current node has been viewed by the current user.'),
      'type' => 'databasics-page', 
    ),
  );

  return $info;
}

Additional resources

• hook_token_info()