My posts are all located at /blog/post-name/

I have a custom taxonomy called a 'Series'. The series can be accessed at /blog/series-name which shows all posts in that series.

What I would like to do is have all posts within the series have their URL changed to /blog/series-name/post-name, but all other posts just stay as /blog/post-name.

How can I do this in functions.php?

1 Answer 1


You can modify the permalinks using the the_permalink filter and add a rewrite rule using add_rewrite_rule to redirect the new permalinks to the standard post link.

function mysite_modify_permalink($url) {
  global $post;
  //if taxonomy archive for Series get term
  $term = is_tax('Series')?get_query_var('term'):'';
  if(empty($term)) { //if no term was found
    //get all Series terms for current post
    $terms = get_the_terms($post, 'Series');
    //if terms were found, take first term found
    if(!empty($terms) && is_array($terms)) $term = $terms[0]->slug;
  //if term was found return a modified permalink url
  //(replace last url segment starting from '/' with '/<term slug><last segment>')
  if(!empty($term)) return preg_replace('#/blog(/[^/]+/?)$#', '/blog/'.$term.'$1', $url);
  //else return original url
  else return $url;
add_filter('the_permalink', 'mysite_modify_permalink');

function mysite_add_rewrule() {
  //get all Series terms
  $terms = get_terms(array('taxonomy' => 'Series'));
  //if terms were found, add a rewrite rule for urls containing one of them
  if(!empty($terms) && is_array($terms)) {
    foreach($terms as $key => $term) $terms[$key] = $term->slug;
    $terms = '(?:' . implode('|', $terms) . ')';
    add_rewrite_rule('^blog/'.$terms.'(/[^/]+/?)$', 'index.php?name=$matches[1]', 'top');
add_action('init', 'mysite_add_rewrule');
  • Hi, this works great for changing the permalinks, but when I click through to the post, the URL does not include the taxonomy slug. It's like a redirect happened but I don't know where from.
    – BadHorsie
    Aug 21, 2017 at 18:48
  • oh perhaps because i redirected to blog/post, and another translation of the url happens. I'm changing it.
    – inarilo
    Aug 21, 2017 at 18:56
  • let me know if this works, i changed just the line with add_rewrite_rule
    – inarilo
    Aug 21, 2017 at 19:02
  • made another change in the line before that, added ?:
    – inarilo
    Aug 21, 2017 at 19:13
  • 1
    i have added index.php in the redirect, maybe that will fix it
    – inarilo
    Aug 23, 2017 at 19:38

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