rewrite endpoints

gistfile1.aw

<?php

/**
 * Blog Rewrite Endpoint
 * Used for filtering blog posts. Ex: most comments
 *
 * @since 1.0
 */
function be_add_blog_rewrite_endpoint() {
	add_rewrite_endpoint( 'filter', EP_ALL );
}
add_action( 'init', 'be_add_blog_rewrite_endpoint' );

/**
 * Blog Filters
 * If using the 'filter' rewrite endpoint, modify the blog query
 *
 * @since 1.0
 * @param $query object
 */
function be_blog_filters( $query ) {
	global $wp_the_query;
	if( $query === $wp_the_query && 'comments' == get_query_var( 'filter' ) )
		$query->set( 'orderby', 'comment_count' );
}
add_action( 'pre_get_posts', 'be_blog_filters' );