PHP - Wordpress - Search - wordpress custom search function that encompasses ACF/advanced custom fields and taxonomies and split expression before request

custom-search-acf-wordpress.php

<?php

**
 * [list_searcheable_acf list all the custom fields we want to include in our search query]
 * each array member is the name (slug) of the key we want to search
 * @return [array] [list of custom fields]
 */
function list_searcheable_acf(){
  $list_searcheable_acf = array("productean", "productidentart", "productnumart", "productauthors", "_sku");
  return $list_searcheable_acf;
}
/**
 * [advanced_custom_search search that encompasses ACF/advanced custom fields and taxonomies and split expression before request]
 * @param  [query-part/string]      $where    [the initial "where" part of the search query]
 * @param  [object]                 $wp_query []
 * @return [query-part/string]      $where    [the "where" part of the search query as we customized]
 * see https://vzurczak.wordpress.com/2013/06/15/extend-the-default-wordpress-search/
 * credits to Vincent Zurczak for the base query structure/spliting tags section
 */
function advanced_custom_search( $where, $wp_query ) {
    global $wpdb;
 
    if ( empty( $where ))
        return $where;

	// 1- get search expression
  	$terms_raw = $wp_query->query_vars[ 's' ];
  	// 2- check search term for XSS attacks
  	$terms_xss_cleared = strip_tags($terms_raw);
  	// 3- do another check for SQL injection, use WP esc_sql
  	$terms = esc_sql($terms_xss_cleared);
  
  
    // explode search expression to get search terms
    $exploded = explode( ' ', $terms );
    if( $exploded === FALSE || count( $exploded ) == 0 )
        $exploded = array( 0 => $terms );
         
    // reset search in order to rebuilt it as we whish
    $where = '';
    
    // get searcheable_acf, a list of advanced custom fields you want to search content in
    $list_searcheable_acf = list_searcheable_acf();
    foreach( $exploded as $tag ) :
        $where .= " 
          AND (
            (". $wpdb->prefix ."posts.post_title LIKE '%$tag%')
            OR (". $wpdb->prefix ."posts.post_content LIKE '%$tag%')
            OR EXISTS (
              SELECT * FROM ". $wpdb->prefix ."postmeta
	              WHERE post_id = ". $wpdb->prefix ."posts.ID
	                AND (";
        foreach ($list_searcheable_acf as $searcheable_acf) :
          if ($searcheable_acf == $list_searcheable_acf[0]):
            $where .= " (meta_key LIKE '%" . $searcheable_acf . "%' AND meta_value LIKE '%$tag%') ";
          else :
            $where .= " OR (meta_key LIKE '%" . $searcheable_acf . "%' AND meta_value LIKE '%$tag%') ";
          endif;
        endforeach;
	        $where .= ")
            )
            OR EXISTS (
              SELECT * FROM ". $wpdb->prefix ."comments
              WHERE comment_post_ID = ". $wpdb->prefix ."posts.ID
                AND comment_content LIKE '%$tag%'
            )
            OR EXISTS (
              SELECT * FROM ". $wpdb->prefix ."terms
              INNER JOIN ". $wpdb->prefix ."term_taxonomy
                ON ". $wpdb->prefix ."term_taxonomy.term_id = ". $wpdb->prefix ."terms.term_id
              INNER JOIN ". $wpdb->prefix ."term_relationships
                ON ". $wpdb->prefix ."term_relationships.term_taxonomy_id = ". $wpdb->prefix ."term_taxonomy.term_taxonomy_id
              WHERE (
          		taxonomy = 'post_tag'
            		OR taxonomy = 'category'          		
            		OR taxonomy = 'product_cat'
            		OR taxonomy = 'product_tag'
          		)
              	AND object_id = ". $wpdb->prefix ."posts.ID
              	AND ". $wpdb->prefix ."terms.name LIKE '%$tag%'
            )
        )";
    endforeach;

  	return $where;
}
 
add_filter( 'posts_search', 'advanced_custom_search', 500, 2 );