How to Use Hook Prepocess Field in Drupal Websites

In this blog, we are going to discuss the implementation of hook preprocess in your drupal websites. We have a special hook to preprocess a field in drupal 7. A hook is hook_preprocess_HOOK(), the first "hook" is the name of your module or theme. The second "HOOK" is the hook you want to preprocess, for example node, block, link, field. But we are going to concentrate on 'field' in this blog.

We can use hook_preprocess_field for different purposes in a field. Be it adding extra class, changing output of a field on a certain condition etc. We can use this in a module file as well as in template.php of our theme.

Sample code on how it is implemented in a module is given below :-

/**
* Implements hook_preprocess_field().
*/

function mymodulename_preprocess_field(&$vars)
{
// do something.
}

Currently the code above works for all fields that you will be having on your drupal web page. So how to make it work for single field only? Answer lies in $vars. In $vars you will get the field name for which you want to make your condition work. You can fetch the field name from $vars['element']['#field_name'].

/**
* Implements hook_preprocess_field().
*/

function mymodulename_preprocess_field(&$vars)
{
if ($vars['element']['#field_name'] == 'my_field_name')
{
// do something.
}
}

You can alter or do anything with the output of the field you use $vars['items']. Some other useful elements in the hook_preprocess_field() are:-

  • Weight
  • Access
  • View mode

I hope the above blog will help you in implementing hook preprocess in your Drupal Websites. For more information on Drupal development you can contact us at info@tekritisoftware.com

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