How can I modify a CCK fields display via a module?

Question

Hi.

I'm working on a drupal module, and one thing that it needs to do is modify the display of cck file fields automatically (using template files is not an option). For example, this array:

$node->field_images[0]['view'];

That is what I would like to get into. The 'view' part will output an image based on the display settings for the content type. I would like to attach a link to each image before the node is displayed to the user.

One thing I've tried:

function mymodule_nodeapi(&$node, $op, $teaser, $page) {
      switch ($op) {
          case 'view':
            $node->content['field_images']['view'] = array(
              '#value' => "hello",
              '#weight' => 10
            );
          break;
      }
 }

This inserts the text one time after the last image. I tried using a foreach to loop through all of them and produced no results at all.

I've also tried this:

function mymodule_nodeapi(&$node, $op, $teaser, $page) {
      switch ($op) {
          case 'view':
              // Attach link           
              foreach($node->field_images as $media) {
                  $media['view'] .= generate_link($node->nid, $media);
              }           
          break;
      }
    }

It seems like it should work, but it doesn't. I've searched everywhere for solutions without any luck.

If someone could help me out I would really appreciate it.

Thanks a lot.

Answer 1

Edit

To modify the CCK values before the page is loaded outside the templating system, use the alter op in hook_nodeapi. view is called before the node is rendered, alter is called after.

---

As you noticed, the CCK fields are not populated in time for the places you're trying to put code. Instead, you need to use a preprocessing function—template_preprocess_node()—which will let you modify values just before the rendered output is displayed.

function mymodule_preprocess_node(&$variables) {
  // $variables['field_name'] contains the CCK array for field_name
}

This won't change the rendered output of $content in your node template (unless you really want to get into resetting $variables['content'], but it will allow you to use $field_name in your template with your preprocessed values.

Alternatively, you could create your own custom formatter for the field, which will affect the rendered output of $content. Check out googletorp's blog post on Creating a field formatter for CCK.