WordPress Custom Taxonomy Plugin Example

custom-taxonomy.php

<?php
// Add custom taxonomies
/*
Plugin Name: WP Beaches Taxonomies
Plugin URI: http://wpbeaches.com/
Description: WP Beaches Custom Taxonomies
Author: Neil Gowran
Version: 1.1.0
Author URI: http://wpbeaches.com
*/

/*Further reference - https://codex.wordpress.org/Function_Reference/register_taxonomy
This example registers the term 'portfolio_category' as the example term in the Category section and 'portfolio_tag' in the Tag example, you need to replace these with the actual term.
The use of _x in certain vales in the array are for translation issues - https://codex.wordpress.org/I18n_for_WordPress_Developers#Disambiguation_by_context
*/
add_action( 'init', 'themeprefix_taxonomies');
function themeprefix_taxonomies() {
	// Hierarchal Taxonomy aka Category style - this example uses portfolio
	$labels = array(
		'name'              => _x( 'Portfolio Category', 'taxonomy general name' ),
		'singular_name'     => _x( 'Portfolio Category', 'taxonomy singular name' ),
		'search_items'      => __( 'Search in Portfolios Categories' ),
		'all_items'         => __( 'All Portfolios Categories' ),
		'most_used_items'   => null,
		'parent_item'       => null,
		'parent_item_colon' => null,
		'edit_item'         => __( 'Edit Portfolio Category' ),
		'update_item'       => __( 'Update Portfolio Category' ),
		'add_new_item'      => __( 'Add new Portfolio Category' ),
		'new_item_name'     => __( 'New Portfolio Category' ),
		'menu_name'         => __( 'Portfolio Category' ),
	);
	$args = array(
		'labels'            => $labels,
		'public'            => true,
		'show_in_nav_menus' => true,
		'show_ui'           => true,
		'show_tagcloud'     => true,
		'hierarchical'      => true,
		'show_admin_column' => true,
		'query_var'         => true,
		'rewrite'           => array( 'slug' => 'portfolio-category' ),
	);
	register_taxonomy( 'portfolio_category', array( 'portfolio', 'menu' ), $args );//add in your CPTS that the Taxonomy is applicable to

	

	// Flat Taxonomy aka Tag like - this example uses portfolio
	$labels = array(
		'name'                       => _x( 'Portfolio Tags', 'taxonomy general name' ),
		'singular_name'              => _x( 'Portfolio Tag', 'taxonomy singular name' ),
		'search_items'               => __( 'Search in Portfolios Tags' ),
		'all_items'                  => __( 'All Portfolios Tags' ),
		'most_used_items'            => null,
		'parent_item'                => null,
		'parent_item_colon'          => null,
		'edit_item'                  => __( 'Edit Portfolio Tag' ),
		'update_item'                => __( 'Update Portfolio Tag' ),
		'add_new_item'               => __( 'Add new Portfolio Tag' ),
		'new_item_name'              => __( 'New Portfolio Tags' ),
		'separate_items_with_commas' => __( 'Separate Portfolios Tags with commas' ),
		'choose_from_most_used'      => __( 'Choose from the most used Portfolios Tags' ),
		'not-found'	             => __( 'No Portfolios Tags found'),
		'menu_name'                  => __( 'Portfolios Tags' ),
	);
	$args = array(
		'labels'                     => $labels,
		'public'                     => true,
		'show_in_nav_menus'          => true,
		'show_ui'                    => true,
		'show_tagcloud'              => true,
		'hierarchical'               => false,
		'show_admin_column'          => true,
		'query_var'                  => true,
		'update_count_callback'      => '_update_post_term_count',
		'rewrite'                    => array( 'slug' => 'portfolio-tag' ),
	);
	register_taxonomy( 'portfolio_tags', array( 'portfolio', 'menu' ), $args );//add in your CPTS that the Taxonomy is applicable to this example links it to regular posts and a 'menu' custom post type
}



//Flush the permalinks - ref - https://codex.wordpress.org/Function_Reference/register_post_type#Flushing_Rewrite_on_Activation
function prefix_my_rewrite_flush() {
    // First, we "add" the custom taxonomies via the above written function.
    // Then we flush the permalinks when the plugin is activated so the new taxonomy archives are readily available.
    themeprefix_taxonomies();
    // ATTENTION: This is *only* done during plugin activation hook in this example!
    // You should *NEVER EVER* do this on every page load!!
    flush_rewrite_rules();
}
register_activation_hook( __FILE__, 'prefix_my_rewrite_flush' );
register_deactivation_hook( __FILE__, 'flush_rewrite_rules' );