Editing Category RSS Feeds

Question

I have the following PHP code below that I would like to add to the category feed in WordPress.

<?php if(get_the_post_thumbnail()): ?>
<featured-item><?php echo wp_get_attachment_url(get_post_thumbnail_id($post->ID)); ?></featured-item>
<?php endif; ?>

I know that I can edit feed-rss2.php to add it into the general feed. But the same code isn't allowing me to add it to the category view of the same RSS feed.

Where do I place this code for the generated RSS feed?

Answer 1

FYI, you should never hack the WordPress core files. Instead, WordPress provides the handy rss2_item action hook. All we need to do is check if we're on a category feed or not:

function wpse_99336_category_feed_item() {

    if ( is_category() && get_the_post_thumbnail() ) {
        printf ( '<featured-item>%s</featured-item>',
            wp_get_attachment_url( get_post_thumbnail_id() )
        );
    }
}
add_action( 'rss2_item', 'wpse_99336_category_feed_item' );