nodereferrer.module

<?php



/**
 * @file
 * Defines a field type for backlinking referencing nodes.
 *
 * @todo
 *    -clear content cache with nodeapi.
 *    -query nids for access on load/view..
 */

/**
 * Implementation of hook_help().
 */
function nodereferrer_help($path, $arg) {
  switch ($path) {
    case 'admin/modules#description':
      return t('<strong>CCK:</strong> Defines a field type for displaying referrers to a node. <em>Note: Requires content.module.</em>');
  }
}

/**
 * Implementation of hook_field_info().
 */
function nodereferrer_field_info() {
  return array(
    'nodereferrer' => array('label' => t('Node Referrers')),
  );
}

/**
 * Implementation of hook_field_settings().
 */
function nodereferrer_field_settings($op, $field) {
  switch ($op) {
    case 'views data':
      $data = content_views_field_views_data($field);
      if (is_array($data)) {
        foreach ($data as $k => $v) {
          $data[$k] = array();
        }
      }
      else {
        $data = array();
      }
      return $data;

    case 'callbacks':
      return array('view' => CONTENT_CALLBACK_CUSTOM);

    case 'form':
      $form = array();
      // Hide unused options
      $form['required'] = array(
        '#type' => 'hidden',
        '#value' => FALSE,
      );
      $form['multiple'] = array(
        '#type' => 'hidden',
        '#value' => 0,
      );

      $form['referrer_types'] = array(
        '#type' => 'checkboxes',
        '#title' => t('Referring Node Types'),
        '#multiple' => TRUE,
        '#default_value' => is_array($field['referrer_types']) ? $field['referrer_types'] : array(),
        '#options' => node_get_types('names'),
      );

      $options = nodereferrer_nodereference_field_options();
      $form['referrer_fields'] = array(
        '#type' => 'checkboxes',
        '#title' => t('Referring Fields'),
        '#multiple' => TRUE,
        '#default_value' => is_array($field['referrer_fields']) ? $field['referrer_fields'] : array(),
        '#options' => $options,
      );

      if (module_exists('translation')) {
        $form['referrer_translations'] = array(
          '#type'  => 'checkbox',
          '#title' => t('Show on translations'),
          '#description' => t('If this is checked, referrers will also show on translations of the referenced node'),
          '#default_value' => is_int($field['referrer_translations']) ? $field['referrer_translations'] : 0,
        );
      }

      $form['referrer_nodes_per_page'] = array(
        '#type' => 'textfield',
        '#title' => t('Referrers Per Page'),
        '#description' => t('Referring nodes to display per page. 0 for no paging.'),
        '#default_value' => !empty($field['referrer_nodes_per_page']) ? $field['referrer_nodes_per_page'] : 0,
      );

      $form['referrer_pager_element'] = array(
        '#type' => 'textfield',
        '#title' => t('Pager element'),
        '#description' => t('Use this to avoid clashes if you have several pagers on one page'),
        '#default_value' => !empty($field['referrer_pager_element']) ? $field['referrer_pager_element'] : 0,
      );

      $form['referrer_order'] = array(
        '#type' => 'select',
        '#title' => t('Refferer Sort Order'),
        '#options' => array(
          'CREATED_ASC' =>  t('Chronological Order'),
          'CREATED_DESC' => t('Reverse Chronological Order'),
          'TITLE_ASC' =>  t('Title Order'),
          'TITLE_DESC' => t('Reverse Title Order'),
        ),
        '#default_value' => strlen($field['referrer_order']) ? $field['referrer_order'] : 'TITLE_ASC',
      );

      return $form;

    case 'save':
      $settings = array('referrer_types', 'referrer_fields', 'referrer_nodes_per_page', 'referrer_pager_element', 'referrer_order');
      if (module_exists('translation')) {
        $settings[] = 'referrer_translations';
      }
      return $settings;
  }
}

/**
 * Implementation of hook_field().
 */
function nodereferrer_field($op, &$node, $field, &$items, $teaser, $page) {
  switch ($op) {
    case 'load':
      $types = isset($field['referrer_types']) ? array_values(array_filter($field['referrer_types'])) : array();
      $fields = isset($field['referrer_fields']) ? array_values(array_filter($field['referrer_fields'])) : array();
      $order = $field['referrer_order'];
      $translations = isset($field['referrer_translations']) ? $field['referrer_translations'] : 0;
      $values = nodereferrer_referrers($node->nid, $fields, $types, $translations, $order);
      // Pass referring node objects into CCK content_load() cache. 24/08/2006 sun
      $items = array();
      foreach ($values as $nid => $rnode) {
        $items[] = $rnode;
      }

      if (count($items) == 0) {
        return array($field['field_name'] => array());
      }

      $output = array(
        'items' => $items,
        'limit' => empty($field['referrer_nodes_per_page']) ? 0 : $field['referrer_nodes_per_page'],
        'element' => empty($field['referrer_pager_element']) ? 0 : $field['referrer_pager_element'],
        'pager' => '',
      );

      return array($field['field_name'] => array($output));

    case 'delete':
    case 'update':
      // clear cache on nodes that refer to me.
      $types = array_values(array_filter($field['referrer_types']));
      $fields = array_values(array_filter($field['referrer_fields']));

      // clear any modules referring to me as my title or other data may change.
      // and nodereference doesn't clear the cache yet.
      foreach (nodereferrer_referrers($node->nid, $fields, $types, false) as $delta => $item) {
        $cid = 'content:' . $item['nid'] . ':' . $item['vid'];
        cache_clear_all($cid, 'cache_page');
      }
      return;
  }
}

/**
 * Implementation of hook_field_formatter_info().
 */
function nodereferrer_field_formatter_info() {
  return array(
    'default' => array(
      'label' => 'Node Title Link (Default)',
      'field types' => array('nodereferrer'),
      'multiple values' => CONTENT_HANDLE_CORE,
    ),
    'plain' => array(
      'label' => 'Node Title Plain Text',
      'field types' => array('nodereferrer'),
      'multiple values' => CONTENT_HANDLE_CORE,
    ),
    'teaser' => array(
      'label' => 'Node Teaser',
      'field types' => array('nodereferrer'),
      'multiple values' => CONTENT_HANDLE_CORE,
    ),
   'full' => array(
      'label' => 'Node Body',
      'field types' => array('nodereferrer'),
      'multiple values' => CONTENT_HANDLE_CORE,
    ),
    'count' => array(
      'label' => 'Node Count',
      'field types' => array('nodereferrer'),
      'multiple values' => CONTENT_HANDLE_CORE,
    ),
  );
}

/**
 * Implementation of hook_theme().
 */
function nodereferrer_theme() {
  return array(
    'nodereferrer_formatter_default' => array(
      'arguments' => array('info' => NULL),
    ),
    'nodereferrer_field_default' => array(
      'arguments' => array('element' => NULL),
    ),
    'nodereferrer_formatter_plain' => array(
      'arguments' => array('element' => NULL),
    ),
    'nodereferrer_field_plain' => array(
      'arguments' => array('element' => NULL),
    ),
    'nodereferrer_formatter_teaser' => array(
      'arguments' => array('element' => NULL),
    ),
    'nodereferrer_field_teaser' => array(
      'arguments' => array('element' => NULL),
    ),
    'nodereferrer_formatter_full' => array(
      'arguments' => array('element' => NULL),
    ),
    'nodereferrer_field_full' => array(
      'arguments' => array('element' => NULL),
    ),
    'nodereferrer_formatter_count' => array(
      'arguments' => array('element' => NULL),
    ),
  );
}

/**
 * Generic formatter function
 */
function nodereferrer_theme_formatter($formatter, $info) {
  $items = isset($info['#item']['items']) ? $info['#item']['items'] : array();
  $limit = isset($info['#item']['limit']) ? $info['#item']['limit'] : 0;
  $element = isset($info['#item']['element']) ? $info['#item']['element'] : array();
  $pager = '';

  if ($limit) {
    // Fake the values set by pager query...
    global $pager_page_array, $pager_total, $pager_total_items;
    $page = isset($_GET['page']) ? $_GET['page'] : '';

    // Convert comma-separated $page to an array, used by other functions.
    $pager_page_array = explode(',', $page);
    // We calculate the total of pages as ceil(items / limit).
    $pager_total_items[$element] = count($items);
    $pager_total[$element] = ceil($pager_total_items[$element] / $limit);
    $pager_page_array[$element] = max(0, min((int)$pager_page_array[$element], ((int)$pager_total[$element]) - 1));

    // only display the select elements.
    if (is_array($items)) {
      $items = array_slice($items, $pager_page_array[$element] * $limit, $limit);
    }

    $pager =  theme('pager', array(), $limit, $element);
  }

  $themed_items = array();
  foreach ($items as $i) {
    $i['field'] = $info; // Add some extra information the themer might like to have
    $themed_items[] = theme('nodereferrer_field_' . $formatter, $i);
  }
  $out = theme('item_list', $themed_items) . $pager;

  return $out;
}

/**
 * Theme functions for 'default' field formatter.
 */
function theme_nodereferrer_formatter_default($info) {
  return nodereferrer_theme_formatter('default', $info);
}

function theme_nodereferrer_field_default($element) {
  return l($element['title'], 'node/' . $element['nid']);
}

/**
 * Theme function for 'plain' field formatter.
 */
function theme_nodereferrer_formatter_plain($info) {
  return nodereferrer_theme_formatter('plain', $info);
}

function theme_nodereferrer_field_plain($element) {
  return strip_tags($element['title']);
}

/**
 * Theme function for 'teaser' field formatter.
 */
function theme_nodereferrer_formatter_teaser($info) {
  return nodereferrer_theme_formatter('teaser', $info);
}

function theme_nodereferrer_field_teaser($element) {
  return node_view(node_load($element['nid']), TRUE);
}

/**
 * Theme function for 'full' field formatter.
 */
function theme_nodereferrer_formatter_full($info) {
  return nodereferrer_theme_formatter('full', $info);
}

function theme_nodereferrer_field_full($element) {
  return node_view(node_load($element['nid']));
}

/**
 * Theme function for 'count' field formatter.
 */
function theme_nodereferrer_formatter_count($info) {
  return count($info['#item']['items']);
}

/**
 * Implementation of hook_widget_info().
 */
function nodereferrer_widget_info() {
  return array(
    'nodereferrer_list' => array(
      'label' => t('Read-Only List'),
      'field types' => array('nodereferrer'),
      'multiple values' => CONTENT_HANDLE_MODULE,
      'callbacks' => array(
        'default value' => CONTENT_CALLBACK_NONE,
       ),
    ),
  );
}

/**
 * Implementation of hook_content_is_empty().
 */
function nodereferrer_content_is_empty($item, $field) {
  return TRUE;
}

/**
 * Get an array of referrer nids, by node.type & field.type
 * @param nid
 *     the nid we want to find referres for
 * @param fieldnames
 *     array of fieldnames to be checked for referrers
 * @param nodetypes
 *     array of node types to be checked for referrers
 * @param translations
 *     boolean if true, also return nodes that referrer to translations of the given node
 */

function nodereferrer_referrers($nid,  $fieldnames = array(), $nodetypes = array(), $translations = 0, $order = 'DESC') {
  if ($nodetypes) {
    $filter_nodetypes = "AND n.type IN ('" . implode("', '", $nodetypes) . "')";
  }
  else {
    $filter_nodetypes = '';
  }
  $fields = content_fields();
  // Set default values of fieldnames.
  if (!count($fieldnames)) {
    $fieldnames = array_keys($fields);
  }

  // For Postgresql compatibility ordered fields should be in SELECT too.
  $select_field = '';
  switch ($order) {
    case 'TITLE_ASC':
      $order = 'n.title ASC';
      break;

    case 'TITLE_DESC':
      $order = 'n.title DESC';
      break;

    case 'ASC':
    case 'CREATED_ASC':
      $order = 'n.created ASC';
      $select_field = ', n.created';
      break;

    default :
    case 'DESC':
    case 'CREATED_DESC':
      $order = 'n.created DESC';
      $select_field = ', n.created';
      break;
  }


  $values = array();
  foreach ($fieldnames as $fieldname) {
    if ($fields[$fieldname]['type'] == 'nodereference') {
      $db_info = content_database_info($fields[$fieldname]);

      if ($translations) {
        $query = "SELECT       n.nid, n.vid, n.title $select_field
                  FROM         {" . $db_info['table'] . "} nr
                  INNER JOIN   {node} current_node ON current_node.nid = %d
                  INNER JOIN   {node} n ON n.vid = nr.vid AND n.status = 1 " . $filter_nodetypes . "
                  LEFT JOIN    {node} translations ON current_node.tnid > 0 AND translations.tnid = current_node.tnid
                  WHERE        (current_node.tnid = 0 AND nr." . $db_info['columns']['nid']['column'] . " = current_node.nid)
                               OR
                               (current_node.tnid > 0 AND nr." . $db_info['columns']['nid']['column'] . " = translations.nid)
                  ORDER BY     " . $order;
      }
      else {
        $query = "SELECT       n.nid, n.vid, n.title $select_field
                  FROM         {" . $db_info['table'] . "} nr
                  INNER JOIN   {node} n ON n.vid = nr.vid AND n.status = 1 " . $filter_nodetypes . "
                  WHERE        nr." . $db_info['columns']['nid']['column'] . " = %d
                  ORDER BY     " . $order;
      }

      $query = db_rewrite_sql($query);
      $result = db_query($query, $nid);

      while ($value = db_fetch_array($result)) {
        // avoid duplicate referrers by using nid as key
        $values[$value['nid']]['nid'] = $value['nid'];
        $values[$value['nid']]['vid'] = $value['vid'];
        $values[$value['nid']]['title'] = $value['title'];
        //Store the nodereference fieldnames in the nodereferrer data in the node,
        //so that it can be looked up without needing to load the referring node.
        $values[$value['nid']]['referrers'][$fieldname] = $fieldname;
      }
    }
  }
  return $values;
}


/**
 * Helper function to create an options list of nodereference fields.
 */
function nodereferrer_nodereference_field_options() {
  $options = array();
  $types = content_fields();
  foreach($types as $type) {
    if ($type['type'] == 'nodereference') {
      $options[$type['field_name']] = $type['field_name'] . ' (' . $type['widget']['label'] . ')';
    }
  }
  return $options;
}

/**
 * Implementation of hook_nodeapi().
 */
function nodereferrer_nodeapi($node, $op) {
  switch ($op) {
    case 'insert':
    case 'update':
    case 'delete':
      // Clear content cache to help maintain proper display of nodes.
      $nids = array();
      $type = content_types($node->type);
      if (!empty($type['fields'])) {
        foreach ($type['fields'] as $field) {
          // Add referenced nodes to nids. This will clean up nodereferrer fields
          // when the referencing node is updated.
          if ($field['type'] == 'nodereference') {
            $node_field = isset($node->$field['field_name']) ? $node->$field['field_name'] : array();
            foreach ($node_field as $delta => $item) {
              $nids[$item['nid']] = $item['nid'];
            }
          }
        }
      }

      // Clear Content cache for nodes that reference the node that is being updated.
      // This will keep nodereference fields up to date when referred nodes are
      // updated. @note this currenlty doesn't work all that well since nodereference
      // doesn't respect publishing states or access control.
      if (isset($node->nid)) {
        $referrers = nodereferrer_referrers($node->nid);
        $referrer_nids = array_keys($referrers);
        $nids = array_merge($nids, $referrer_nids);
      }

      foreach ($nids as $nid) {
        $cid = "content:$nid:";
        // define a table to delete from or else this complains
        cache_clear_all($cid, 'cache_content', TRUE);
      }
  }
}

/**
 * Implementation of hook_views_api().
 */
function nodereferrer_views_api() {
  return array(
    'api' => '2.0',
    'path' => drupal_get_path('module', 'nodereferrer') . '/views',
  );
}