I want to add a custom field in the rss title of each post, but don't want it to be shown on the site

Question

I've seen that other sites have done this but didn't manage to do it myself.

I have certain custom fields for each post and I want one of these custom fields to be shown in the RSS feed in the title for each item after the item's actual title. For example, if the post is named "Abracadabra and hocus pocus" and is written by James A. Author I would like the feed item title to be "Abracadabra and hocus pocus by James A. Author".

How can this be done?

Answer 1

I've never actually tried this, but I think the following should work:

function wpse_96096_append_author( $title, $post_id ) {
    if( is_feed() ) {
        $author = get_post_meta( $post_id, '{YOUR CUSTOM FIELD KEY}', true );
        $title = $title . ' by ' . $author;
    }
    return $title;
}
add_filter( 'the_title', 'wpse_96096_append_author', 10, 2 );

What this does is add a filter to the title field that is only applied when is_feed() returns true. When it does, it queries the custom field and tacks it on to the title.