Need help with Custom Taxonomy + Custom Post Type

Question

I am trying to get the URL working for custom post type "our-work" without success. When I created custom post type (our-work) post and assign to custom category sustainability and check the post to be not found. The url address does not appear to be like this our-work/sustainability/project-post-name but our-work/project-name-project. Could anyone correct me on this code and why it not working?

// Project Custom Post
 function create_post_type() {
    register_post_type( 'our-work',
        array(
            'labels' => array(
                'name'=> _('Our Work'),
                'singular_name' => _('Our Work')
             ),
            'public' => true,
            'has_archive' => true,
            'taxonomies'  => array( 'projects' ),
            'hierarchical'        => true,
            'capability_type'     => 'post',
             'publicly_queryable'  => true,
            'show_in_nav_menus'   => true,
             'show_in_menu'        => true,
            'supports'            => array( 'title', 'editor', 'excerpt', 'author', 'thumbnail', 'revisions', ),
        )
    );
}
add_action( 'init', 'create_post_type' );

//hook into the init action and call create_book_taxonomies when it fires
 
add_action( 'init', 'create_subjects_hierarchical_taxonomy', 0 );
 
//create a custom taxonomy name it subjects for your posts
 
function create_subjects_hierarchical_taxonomy() {
 
// Add new taxonomy, make it hierarchical like categories
//first do the translations part for GUI
 
  $labels = array(
    'name' => _x( 'Projects', 'taxonomy general name' ),
    'singular_name' => _x( 'Project', 'taxonomy singular name' ),
    'search_items' =>  __( 'Search Project' ),
    'all_items' => __( 'All Projects' ),
    'parent_item' => __( 'Parent Project' ),
    'parent_item_colon' => __( 'Parent Project:' ),
    'edit_item' => __( 'Edit Subject' ), 
    'update_item' => __( 'Update Subject' ),
    'add_new_item' => __( 'Add New Subject' ),
    'new_item_name' => __( 'New Subject Name' ),
    'menu_name' => __( 'Projects' ),
  );    
 
// Now register the taxonomy
  register_taxonomy('projects',array('our-work'), array(
    'hierarchical' => true,
    'labels' => $labels,
    'show_ui' => true,
    'show_in_rest' => true,
    'show_admin_column' => true,
    'query_var' => true,
    'rewrite' => array( 'slug' => 'our-work' ),
  ));
 
}

Answer 1

why it not working

Because your post type's permalink structure (which defaults to our-work/<post name/slug>) does not contain the category.

So if you want the permalink structure for your post type (our-work) be our-work/<category>/<post name/slug>, here's one way that works in WordPress 5.6 & 5.5, but uses just one of the post categories:

1. Add the <category> part to the post type's rewrite slug — here we're using %projects% as the category placeholder, but you can use other tag like %project_cats%:

   register_post_type( 'our-work', array(
       'rewrite' => array( 'slug' => 'our-work/%projects%' ),
       // your other args
   ) );
   

2. Use the post_type_link hook to replace the above part (i.e. %projects%) with the actual category slug:

   add_filter( 'post_type_link', 'my_post_type_link', 10, 2 );
   function my_post_type_link( $post_link, $post ) {
       if ( $post && 'our-work' === $post->post_type ) {
           // Get all the "projects" terms assigned to the post.
           $terms = get_the_terms( $post, 'projects' );
   
           // But use only the first term ($terms[0]) which is normally the most recent
           // term assigned to the post. So if you assigned it the terms Foo and later
           // Bar, $terms[0] would be the Bar term.
           $post_link = str_replace( '%projects%', $terms[0]->slug, $post_link );
       }
   
       return $post_link;
   }
   

That's all, and be sure to flush the rewrite rules (just visit the permalink settings page).