How do I retrieve node data for a referenced node in a template file?

Question

I have two content types, Event and Gallery. Each Event has a node-reference field to a gallery. I am now trying to style the gallery node page from inside the template file. I need to have a way of creating a link which links back to its parent, the Event.

How can I find this information?

Answer 1

it seems you need to know value of node which is referring the current node. I am assuming machine name for the refernce field you have on event content type as "field_event_gallery"

In your custom module or template.php // function to get backrefernce value.

function mymodulename_get_back_refernce_value($current_nid) {
  $nids = array();
  $results = db_select('field_data_field_event_gallery','n')
            ->fields('n',array('entity_id'))
            ->condition('field_event_gallery_nid',$current_nid)
            ->execute()
            ->fetchAll();
  if(is_array($results) && count($results) > 0) {
    foreach($results as $result) {
      $nids[] = $result->entity_id
    }
  }
  return $nids;
}

Now in your theme template.php use template_preprocess_node(),something like below

function MYTHEME_preprocess_node(&$variables) {
  $node = $variables['node'];
  if ($node->type == 'gallery') {
    //get referring nids
    $referring_nids = mymodulename_get_back_refernce_value($variables['node']->nid);
   if(count($referring_nids) > 0) {
     foreach($referring_nids as $referring_nid) {
       $referring_node = node_load($referring_nid);
       $variables['parent_event_link'][$referring_nid] = l(t('View parent event: @event_title', array('@event_title' => $referring_node->title)), 'node/' . $referring_nid);
   }
  }
}

finally in your template loop through $variables['parent_event_link'] and print it.

My codes are not tested, you have to debug to make them workign for you

Answer 2

The best way to prepare this for template is through hook_preprocess_node() implementation.

This code should be in your theme's template.php file:

function MYTHEME_preprocess_node(&$variables) {
  $node = $variables['node'];
  if ($node->type == 'gallery') {
    // You can add new attributes to the $variables variable and they will be
    // available automatically in the node template file as direct variables.
    $variables['parent_event_link'] = l(t('View parent event: @event_title', array('@event_title' => $variables['field_gallery_event'][0]['node']->title)), 'node/' . $variables['field_gallery_event'][0]['nid']);
  }
}

And in your node.tpl.php or node--gallery.tpl.php file you can use:

<?php print $parent_event_link; ?>