WordPress Plugin: T5 Short Feed

t5-short-feed.php

<?php # -*- coding: utf-8 -*-
/**
 * Plugin Name: T5 Short Feed
 * Plugin URI:  https://gist.github.com/toscho/86d6ebcdec3be4d04af8
 * Description: Creates a feed with just the excerpt, no matter what you have set for the main feed. Please visit the permalinks page once after activation. The feed is then available at <code>/feed/summary/</code>. Requires PHP 5.3.
 * Version:     07.05.15
 * Required:    4.2
 * Author:      Thomas Scholz <info@toscho.de>
 * Author URI:  http://toscho.de
 * License:     MIT
 * License URI: http://www.opensource.org/licenses/mit-license.php
 */

add_action( 'wp_loaded', function() {
	add_feed( 'summary', function() {
		add_filter( 'pre_option_rss_use_excerpt', '__return_true' );
		require ABSPATH . WPINC . '/feed-rss2.php';
	});
});