Reply To: Accept only unique values

• John Huebner

• November 4, 2016 at 10:30 pm

Since posting that I’ve leaned some thing, like I don’t need to create a post ID field and hide it. I’ve also refined the function so that I can use the same function for any field where I want to have a unique value, just add it as a filter to any field you want to be unique.

<?php 
  
  add_filter('acf/validate_value/name='.$field_name, 'acf_unique_value_field', 10, 4);
  
  function acf_unique_value_field($valid, $value, $field, $input) {
    if (!$valid || (!isset($_POST['post_ID']) && !isset($_POST['post_id']))) {
      return $valid;
    }
    if (isset($_POST['post_ID'])) {
      $post_id = intval($_POST['post_ID']);
    } else {
      $post_id = intval($_POST['post_id']);
    }
    if (!$post_id) {
      return $valid;
    }
    $post_type = get_post_type($post_id);
    $field_name = $field['name'];
    $args = array(
      'post_type' => $post_type,
      'post_status' => 'publish, draft, trash',
      'post__not_in' => array($post_id),
      'meta_query' => array(
        array(
          'key' => $field_name,
          'value' => $value
        )
      )
    );
    $query = new WP_Query($args);
    if (count($query->posts)){
      return 'This Value is not Unique. Please enter a unique '.$field['label'];
    }
    return true;
  }
    
?>

I did notice an error in your code, this:

'key' => $field['type'],

should be

'key' => $field['name'],