Custom WordPress Rewrite Rule to Combine Taxonomy and Post Type | www.ibenic.com/custom-wordpress-rewrite-rule-combine-taxonomy-post-type

change_link.php

<?php

function change_link( $permalink, $post ) {
    
    if( $post->post_type == 'resources_post_type' ) {
        $resource_terms = get_the_terms( $post, 'resource_type' );
        $term_slug = '';
        if( ! empty( $resource_terms ) ) {
            foreach ( $resource_terms as $term ) {

                // The featured resource will have another category which is the main one
                if( $term->slug == 'featured' ) {
                    continue;
                }

                $term_slug = $term->slug;
                break;
            }
        }
        $permalink = get_home_url() ."/resources/" . $term_slug . '/' . $post->post_name;
    }
    return $permalink;

}
add_filter('post_type_link',"change_link",10,2);

post_type.php

<?php

add_action('init', 'cpt_resources');

function cpt_resources() {
    $labels = array(
        'name' => _x('Resources', 'snt'),
        'singular_name' => _x('Resource', 'snt'),
        'add_new' => _x('Add Resource', 'snt'),
        'add_new_item' => __('Add Resource'),
        'edit_item' => __('Edit Resource'),
        'new_item' => __('New Resource'),
        'view_item' => __('View Resource'),
        'search_items' => __('Search Resources'),
        'not_found' =>  __('Nothing found'),
        'not_found_in_trash' => __('Nothing found in Trash'),
        'parent_item_colon' => ''
    );
 
    $args = array(
        'labels' => $labels,
        'taxonomies' => array('resource_type'),
        'public' => true,
        'publicly_queryable' => true,
        'show_ui' => true,
        'query_var' => true,
        'rewrite' => true,
        'capability_type' => 'post',
        'hierarchical' => false,
        'menu_position' => null,
        'supports' => array('title','thumbnail', 'editor' ),
      ); 
 
    register_post_type( 'resources_post_type' , $args );

     
}

rewrite_rule.php

<?php

function resources_cpt_generating_rule($wp_rewrite) {
    $rules = array();
    $terms = get_terms( array(
        'taxonomy' => 'resource_type',
        'hide_empty' => false,
    ) );
   
    $post_type = 'resources_post_type';

    foreach ($terms as $term) {    
                
        $rules['resources/' . $term->slug . '/([^/]*)$'] = 'index.php?post_type=' . $post_type. '&resources_post_type=$matches[1]&name=$matches[1]';
                        
    }

    // merge with global rules
    $wp_rewrite->rules = $rules + $wp_rewrite->rules;
}
add_filter('generate_rewrite_rules', 'resources_cpt_generating_rule');

taxonomy.php

<?php

function resource_type() {

    $labels = array(
        'name'                       => _x( 'Resource Types', 'Taxonomy General Name', 'snt' ),
        'singular_name'              => _x( 'Resource Type', 'Taxonomy Singular Name', 'snt' ),
        'menu_name'                  => __( 'Resource Types', 'snt' ),
        'all_items'                  => __( 'All Items', 'snt' ),
        'parent_item'                => __( 'Parent Item', 'snt' ),
        'parent_item_colon'          => __( 'Parent Item:', 'snt' ),
        'new_item_name'              => __( 'New Item Name', 'snt' ),
        'add_new_item'               => __( 'Add New Item', 'snt' ),
        'edit_item'                  => __( 'Edit Item', 'snt' ),
        'update_item'                => __( 'Update Item', 'snt' ),
        'view_item'                  => __( 'View Item', 'snt' ),
        'separate_items_with_commas' => __( 'Separate items with commas', 'snt' ),
        'add_or_remove_items'        => __( 'Add or remove items', 'snt' ),
        'choose_from_most_used'      => __( 'Choose from the most used', 'snt' ),
        'popular_items'              => __( 'Popular Items', 'snt' ),
        'search_items'               => __( 'Search Items', 'snt' ),
        'not_found'                  => __( 'Not Found', 'snt' ),
        'no_terms'                   => __( 'No items', 'snt' ),
        'items_list'                 => __( 'Items list', 'snt' ),
        'items_list_navigation'      => __( 'Items list navigation', 'snt' ),
    );
    $args = array(
        'labels'                     => $labels,
        'hierarchical'               => true,
        'public'                     => true,
        'show_ui'                    => true,
        'show_admin_column'          => true,
        'show_in_nav_menus'          => true,
        'show_tagcloud'              => true,
        'rewrite'                    => array('slug' => 'resources')
    );
    register_taxonomy( 'resource_type', array( 'resources_post_type' ), $args );

}
add_action( 'init', 'resource_type', 0 );