Find related posts with Elasticpress

elasticpress-mlt.php

<?php 


add_filter('ep_formatted_args', 'my_ep_formatted_args', 10, 2 );

function my_ep_formatted_args( $formatted_args, $args ) {
  // Handle more like this queries. WP_QUery arg formatting is: array( 'more_like' => $post_id )
  if ( ! empty( $args['more_like'] ) ) {
      $formatted_args['query'] = array(
          'more_like_this' => array(
              'ids'             => is_array($args['more_like']) ? $args['more_like'] : array( $args['more_like'] ),
              // Add any field to search in
              'fields'          => array('post_title', 'post_content', 'terms.post_tag.name'),
              // You can tweak elasticsearch parameters for better results
              'min_term_freq'   => 1,
              'max_query_terms' => 12,
              'min_doc_freq'    => 1
          )
      );
  }
  
  return $formatted_args;

}