Display Related Posts (WordPress)

relatedposts.php

function get_related_posts($args)
{
	global $post;
  
	$defaults = array (
		'num'       => '4', // number of posts to retrieve
		'post_type' => 'any', // any post type
		'post_id'   => $post->ID, // get current post ID
		'taxonomy'  => 'tag', // taxonomy term
		'orderby'   => 'rand' // defaults to random
	);

	$args = wp_parse_args($args, $defaults);
	extract($args, EXTR_SKIP);

	$taxonomies = wp_get_post_terms( $post_id, $taxonomy );
	
	if ( $taxonomies ) {
		$tax_ids = array();
		foreach( $taxonomies as $term ) $tax_ids[] = $term->term_id;
		$args = array(
			'tax_query'      => array(
				array(
					'taxonomy'   => $taxonomy,
					'terms'      => $tax_ids,
					'operator'   => 'IN'
				)
			),
			'post_type'      => $post_type,
			'post__not_in'   => array( $post_id ),
			'posts_per_page' => $num,
			'orderby'        => $orderby,
		);
	}
	
	$posts = get_posts($args);
	
	return $posts;
}