Yoast custom feed template as add_feed function?

Question

I'm trying to make Yoast's Custom RSS feeds post display in an add_feed function.

Just putting Yoast's snippet inside add_feed results in:

ERROR: feedname is not a valid feed template.

I have tried two rewrite functions, but to no avail. What could I be missing?

Yoast's function untouched:

<?php
/*
Template Name: Custom Feed
*/

$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;
}

$posts = query_posts('showposts='.$numposts);

$lastpost = $numposts - 1;

header("Content-Type: application/rss+xml; charset=UTF-8");
echo '<?xml version="1.0"?>';
?><rss version="2.0">
<channel>
  <title>Yoast E-mail Update</title>
  <link><a class="linkclass" href="http://yoast.com/">http://yoast.com/</a></link>
  <description>The latest blog posts from Yoast.com.</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><a class="linkclass" href="mailto:[email protected]">[email protected]</a></managingEditor>
<?php foreach ($posts as $post) { ?>
  <item>
    <title><?php echo get_the_title($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 } ?>
</channel>
</rss>

Function one:

function myPlugin_add_feed(  ) {
  global $wp_rewrite;
  add_feed('feedname', 'my_feed');
  add_action('generate_rewrite_rules', 'myPlugin_rewrite_rules');
  $wp_rewrite->flush_rules();
}
add_action('init', 'myPlugin_add_feed');

and function two:

function custom_feed_rewrite($wp_rewrite) {
$feed_rules = array(
'feed/(.+)' => 'index.php?feed=' . $wp_rewrite->preg_index(1),
'(.+).xml' => 'index.php?feed='. $wp_rewrite->preg_index(1)
);
$wp_rewrite->rules = $feed_rules + $wp_rewrite->rules;
}
add_filter('generate_rewrite_rules', 'custom_feed_rewrite');

Answer 1

You have add_feed('feedname', 'my_feed'); but no my_feed function to actually generate the feed output.

Create a my_feed function and have it call the template to generate the feed output. Like this:

function my_feed() {
  include 'path-to-that-template-file.php';
}
add_feed('feedname','my_feed');

Then regenerate your permalinks, one time only, by resaving the permalink settings.

Also, you don't need any of that extra rewrite nonsense at all. Just the add_feed is enough. WP handles the rest, and your feed will be at /feed/feedname.

Answer 2

First, correct way is to use add_feed(), but you should not touch rewrite. add_feed() handles that by itself.

Second, you didn't provide your callback my_feed() function? I am not sure but from that error message I think it fails to get hooked properly.