Reply To: Setting Parent Posts from Frontend

• John Huebner

• February 9, 2021 at 12:07 am

To set the parent post from the front end you need a relationship field that is only available on the front end. Set this up to start. Add a post object field that only allows one selection.

Create the following filters for your field in functions.php

// only show field on front of site
// https://www.advancedcustomfields.com/resources/acf-prepare_field/
add_filter('acf/prepare_field/name=YOUR FIELD NAME HERE', 'field_only_on_front');
function field_only_on_front($field) {
  if (is_admin()) {
    return false;
  }
  return $field;
}

// alter the acf query of the post object field to only show top level posts
https://www.advancedcustomfields.com/resources/acf-fields-post_object-query/
add_filter('acf/fields/post_object/query/name=YOUR FIELD NAME HERE', 'only_top_level_posts', 20, 3);
function only_top_level_posts($args, $field, $post_id) {
  $args['post_parent'] = 0;
  return $args;
}

After you do this set up your taxonomy field to return term objects

Once all that is done then then create an acf/save_post filter in functions.php

add_action('acf/save_post', 'update_and_save_journal_post');
function update_and_save_journal_post($post_id) {
  // make sure to only do this on the right post type
  $post_type = get_post_type($post_id);
  if ($post_type != 'YOUR POST TYPE HERE') {
    return;
  }
  // get the post
  $post = get_post($post_id);
  // get the parent, unformatted, ID only
  $parent = get_field('YOUR POST OBJECT FIELD', $post_id, false);
  if ($parent ) {
    $post->post_parent = $parent;
  }
  
  // get the taxonomy field
  $terms = get_field('YOUR TAXONOMY FIELD;, $post_id);
  if (!empty($terms) && !is_wp_error($terms)) {
    $term = terms[0];
    $post->post_title = $term->name.$post->post_title;
  }
  // remove this action so that an infinite loop is not created
  remove_filter('acf/save_post', 'update_and_save_journal_post');
  // update the post
  wp_update_post($post);
  // re-add this filter
  add_action('acf/save_post', 'update_and_save_journal_post');
}

Please note that none of the above code has been tested for syntax errors.