WordPress - Events and Projects post types each with categories

gistfile1.php

<?

// EVENTS
add_action('init', '_init_event_post_type');

function _init_event_post_type() {

	// Create taxonomy
	register_taxonomy(
		'event_category',
		array( 'event' ),
		array(
			'labels' => array(
				'name' => __( 'Event Categories' ),
				'singular_name' => __( 'Event Category' ),
				'search_items' => __( 'Search Categories' ),
				'popular_items' => __( 'Popular Categories' ),
				'all_items' => __( 'All Categories' ),
				'parent_item' => __( 'Parent Category' ),
				'parent_item_colon' => __( 'Parent Categories:' ),
				'edit_item' => __( 'Edit Category' ),
				'update_item' => __( 'Update Category' ),
				'add_new_item' => __( 'Add New Category' ),
				'new_item_name' => __( 'New Category' ),
			),
			'public' => true,
			'show_in_nav_menus' => true,
			'show_ui' => true,
			'publicly_queryable' => false,
			'exclude_from_search' => false,
			'hierarchical' => true,
			'query_var' => true,
			'rewrite' => array( 'slug' => 'events/filter', 'with_front' => false ),
		)
	);

	// Create post type
	register_post_type( 'event',
		array(
			'capability_type' => 'post',
			'hierarchical' => false,
			'public' => true,
			'show_ui' => true,
			'publicly_queryable' => true,
			'exclude_from_search' => false,
			'menu_position' => 30,
			'has_archive' => true,
			'query_var' => true,
			'rewrite' => array( 'slug' => 'events/%event_category%', 'with_front' => false ),
			'supports' => array('title', 'editor', 'excerpt', 'thumbnail'),
			'labels' => array(
				'name' => __( 'Events' ),
				'singular_name' => __( 'Event' ),
				'add_new' => __( 'Add New' ),
				'add_new_item' => __( 'Add New Event' ),
				'edit' => __( 'Edit' ),
				'edit_item' => __( 'Edit Event' ),
				'new_item' => __( 'New Event' ),
				'view' => __( 'View Event' ),
				'view_item' => __( 'View Event' ),
				'search_items' => __( 'Search Event' ),
				'not_found' => __( 'No Events found' ),
				'not_found_in_trash' => __( 'No Events found in Trash' )
			)
		)
	);

	// Make permalinks for events pretty (add category to URL)
	add_filter('post_type_link', 'event_permalink_filter_function', 1, 3);
	function event_permalink_filter_function( $post_link, $id = 0, $leavename = FALSE ) {
	    if ( strpos('%event_category%', $post_link) === 'FALSE' ) {
	      return $post_link;
	    }
	    $post = get_post($id);
	    if ( !is_object($post) || $post->post_type != 'event' ) {
	      return $post_link;
	    }
	    $terms = wp_get_object_terms($post->ID, 'event_category');
	    if ( !$terms ) {
	      return str_replace('events/%event_category%/', '', $post_link);
	    }
	    return str_replace('%event_category%', $terms[0]->slug, $post_link);
	}

}

// PROJECTS
add_action('init', '_init_project_post_type');

function _init_project_post_type() {

	// Create taxonomy
	register_taxonomy(
		'project_category',
		array( 'project' ),
		array(
			'labels' => array(
				'name' => __( 'Project Categories' ),
				'singular_name' => __( 'Project Category' ),
				'search_items' => __( 'Search Categories' ),
				'popular_items' => __( 'Popular Categories' ),
				'all_items' => __( 'All Categories' ),
				'parent_item' => __( 'Parent Category' ),
				'parent_item_colon' => __( 'Parent Categories:' ),
				'edit_item' => __( 'Edit Category' ),
				'update_item' => __( 'Update Category' ),
				'add_new_item' => __( 'Add New Category' ),
				'new_item_name' => __( 'New Category' ),
			),
			'public' => true,
			'show_in_nav_menus' => true,
			'show_ui' => true,
			'publicly_queryable' => false,
			'exclude_from_search' => false,
			'hierarchical' => true,
			'query_var' => true,
			'rewrite' => array( 'slug' => 'projects/filter', 'with_front' => false ),
		)
	);

	// Create post type
	register_post_type( 'project',
		array(
			'capability_type' => 'post',
			'hierarchical' => false,
			'public' => true,
			'show_ui' => true,
			'publicly_queryable' => true,
			'exclude_from_search' => false,
			'menu_position' => 30,
			'has_archive' => true,
			'query_var' => true,
			'rewrite' => array( 'slug' => 'projects/%project_category%', 'with_front' => false ),
			'supports' => array('title', 'editor', 'excerpt', 'thumbnail'),
			'labels' => array(
				'name' => __( 'Projects' ),
				'singular_name' => __( 'Project' ),
				'add_new' => __( 'Add New' ),
				'add_new_item' => __( 'Add New Project' ),
				'edit' => __( 'Edit' ),
				'edit_item' => __( 'Edit Project' ),
				'new_item' => __( 'New Project' ),
				'view' => __( 'View Project' ),
				'view_item' => __( 'View Project' ),
				'search_items' => __( 'Search Project' ),
				'not_found' => __( 'No Projects found' ),
				'not_found_in_trash' => __( 'No Projects found in Trash' )
			)
		)
	);

	// Make permalinks for projects pretty (add category to URL)
	add_filter('post_type_link', 'project_permalink_filter_function', 1, 3);
	function project_permalink_filter_function( $post_link, $id = 0, $leavename = FALSE ) {
	    if ( strpos('%project_category%', $post_link) === 'FALSE' ) {
	      return $post_link;
	    }
	    $post = get_post($id);
	    if ( !is_object($post) || $post->post_type != 'project' ) {
	      return $post_link;
	    }
	    $terms = wp_get_object_terms($post->ID, 'project_category');
	    if ( !$terms ) {
	      return str_replace('projects/%project_category%/', '', $post_link);
	    }
	    return str_replace('%project_category%', $terms[0]->slug, $post_link);
	}

	// Make permalinks work! (must come after your last CPT)
	flush_rewrite_rules(); 

}

// Fixes /page/2 bug for archives
// http://wordpress.stackexchange.com/a/16929/9244
add_action( 'init', 'wpse16902_init' );
function wpse16902_init() {
    $GLOBALS['wp_rewrite']->use_verbose_page_rules = true;
}

add_filter( 'page_rewrite_rules', 'wpse16902_collect_page_rewrite_rules' );
function wpse16902_collect_page_rewrite_rules( $page_rewrite_rules )
{
    $GLOBALS['wpse16902_page_rewrite_rules'] = $page_rewrite_rules;
    return array();
}

add_filter( 'rewrite_rules_array', 'wspe16902_prepend_page_rewrite_rules' );
function wspe16902_prepend_page_rewrite_rules( $rewrite_rules )
{
    return $GLOBALS['wpse16902_page_rewrite_rules'] + $rewrite_rules;
}

?>