How Can I Change a Taxonomy URL Based On The Originating URL?

Question

I previously wrote a question about rewriting a URL based on an originating URL and Milo provided me with a working answer for pages/posts. But now I am trying to do a taxonomy rewrite and the same functionality seems to break things.

Here is my code:

function lqd_series_link( $term_id, $taxonomy ) {
  if ( $taxonomy == 'gc-sermon-series' && isset( $wp_query->query_vars['app-view'] ) ) {
    return $taxonomy; // I've also tried $link
  }
  return $taxonomy;
}
add_filter( 'term_link', 'lqd_series_link' );

What is strangest is what this results in. So if I do the code as Milo instructed on the question linked above I end up with a URL for pages like:

https://liquidchurch.com/messages/app-view/

But when I use the above code I end up with the same exact thing:

https://liquidchurch.com/messages/app-view/

Thoughts?

Answer 1

The term_link filter has a different signature for its callback function than the page_link filter, meaning the arguments in your callback are different. (Also note you'll need to explicitly set the argument number when you call add_filter because by default add_filter will only setup 1 argument. For example:

add_filter( 'term_link', 'lqd_series_link', 10, 3 ); // Where 3 is the number of arguments for your callback function

Then in your callback:

function lqd_series_link( $url, $term, $taxonomy ) {
    global $wp_query;
    if ( $taxonomy == 'gc-sermon-series' && isset( $wp_query->query_vars['app-view'] ) ) {
        return $url . 'app-view/';
    }
    return $url;
}