WordPress custom post type permalink rewrite structure rule for taxonomies.

custom-post-type-rewrite.php

<?php
/**
 * WP_Dev_Rewrites initial setup
 *
 * @since 1.0.0
 */
if( !class_exists('WP_Dev_Rewrites') ) {

	class WP_Dev_Rewrites {

		private static $instance;
		private $post_types;

		/**
		 *  Initiator
		 */
		public static function get_instance(){
			if ( ! isset( self::$instance ) ) {
				self::$instance = new WP_Dev_Rewrites();
			}
			return self::$instance;
		}

		/**
		 *  Constructor
		 */
		public function __construct() {

			$this->post_types = array(
				// 'post-type-1' => '%taxonomy-1%/%taxonomy-2%',
				// 'post-type-2' => '%another-taxonomy-1%',
			);

			add_filter( 'rewrite_rules_array', array( $this, 'rules' ) );
			add_filter( 'post_type_link', array( $this, 'filter_post_type_link' ), 10, 2 );
			add_filter( 'register_post_type_args', array( $this, 'post_type_args' ), 10, 2 );
			// add_filter( 'register_taxonomy_args', array( $this, 'taxonomy_args' ), 10, 3 );
		}

		// function taxonomy_args( $args, $taxonomy, $object_type ) {
		// 	foreach ($this->post_types as $post_type => $post_taxonomies) {

		// 		$taxonomies = explode('/', $post_taxonomies );

		// 		foreach ($taxonomies as $taxonomy_key => $stored_taxonomy) {
		// 			$plain_slug = str_replace('%', '', $stored_taxonomy);
		// 			$args['rewrite'] = array(
		// 			    'slug' => $post_type,
		// 			    'with_front' => true
		// 		    );
		// 		}
		// 	}
	
		// 	return $args;
			
		// }

		/**
		 * Tell WordPress how to interpret our project URL structure
		 *
		 * @param array $rules Existing rewrite rules
		 * @return array
		 */
		function rules( $rules ) {

			$new = array();

			foreach ($this->post_types as $post_type => $value) {
				$new[ $post_type . '/([^/]+)/(.+)/?$'] = 'index.php?'.$post_type.'=$matches[2]';
			}

			return array_merge( $new, $rules );	 // Ensure our rules come first
		}
		

		/**
		 * Handle the '%taxonomy%' URL placeholder
		 *
		 * @param str $link The link to the post
		 * @param WP_Post object $post The post object
		 * @return str
		 */
		function filter_post_type_link( $link, $post ) {
			foreach ($this->post_types as $key => $post_taxonomies) {

				$taxonomies = explode('/', $post_taxonomies );

				foreach ($taxonomies as $taxonomy_key => $taxonomy) {
					$taxonomy_slug = str_replace('%', '', $taxonomy);
					$term = get_the_terms( $post->ID, $taxonomy_slug );
					if ( $term ) {
						$link = str_replace( $taxonomy, current( $term )->slug, $link );
					}
				}

				
			}
			
			return $link;
		}
		

		function post_type_args( $args, $post_type ) {

			if( isset( $this->post_types[ $post_type ] ) && ! empty( $this->post_types[ $post_type ] ) ) {
				$args['rewrite'] = array(
				    'slug' => $post_type . '/' . $this->post_types[ $post_type ],
				    'with_front' => true
				);
			}
			
			return $args;
		}

	}

	/**
	 *  Kicking this off by calling 'get_instance()' method
	 */
	WP_Dev_Rewrites::get_instance();

}