rss-event.php

<?php
/*
Template Name: Events RSS
*/

$numposts = 5;

function yoast_rss_date( $timestamp = null ) {
  $timestamp = ($timestamp==null) ? time() : $timestamp;
  echo date(DATE_RSS, $timestamp);
}

function yoast_rss_text_limit($string, $length, $replacer = '...') { 
  $string = strip_tags($string);
  if(strlen($string) > $length) 
    return (preg_match('/^(.*)\W.*$/', substr($string, 0, $length+1), $matches) ? $matches[1] : substr($string, 0, $length)) . $replacer;   
  return $string; 
}



$args = array(
	'post__not_in' => get_option('sticky_posts'),
   'meta_key' => 'is_event',
   'orderby' => 'meta_value_num',
   'order' => 'DESC',
   'posts_per_page' => -1

 
);
$the_query = new WP_Query( $args );	 
$lastpost = $numposts - 1;
header("Content-Type: application/rss+xml; charset=UTF-8");
echo '<?xml version="1.0"?>';
?>

<rss version="2.0">
<channel>
  <title>MIT Libraries Events</title>
  <link>//libraries.mit.edu/news/events/</link>
  <description>The latest events from the MIT Libraries</description>
  <language>en-us</language>
  <pubDate><?php yoast_rss_date( strtotime($ps[$lastpost]->post_date_gmt) ); ?></pubDate>
  <lastBuildDate><?php yoast_rss_date( strtotime($ps[$lastpost]->post_date_gmt) ); ?></lastBuildDate>
  <managingEditor>hartman@mit.edu (Stephanie Hartman)</managingEditor>
<?php while ( $the_query->have_posts() ) : $the_query->the_post(); ?>

  <item>
    <title><?php echo get_the_title($post->ID); ?></title>
    <link><?php echo get_permalink($post->ID); ?></link>
    <description><?php echo '<![CDATA['.yoast_rss_text_limit($post->post_content, 500).'<br/><br/>Keep on reading: <a href="'.get_permalink($post->ID).'">'.get_the_title($post->ID).'</a>'.']]>';  ?></description>
    <pubDate><?php yoast_rss_date( strtotime($post->post_date_gmt) ); ?></pubDate>
    <guid><?php echo get_permalink($post->ID); ?></guid>
  </item>
<?php endwhile; ?>
</channel>
</rss>