File Content: primary-category.php <?php namespace Yoast\WP\SEO\Integrations; use stdClass; use WP_Error; use WP_Post; use WPSEO_Primary_Term; use Yoast\WP\SEO\Conditionals\Primary_Category_Conditional; /** * Adds customizations to the front end for the primary category. */ class Primary_Category implements Integration_Interface { /** * Returns the conditionals based on which this loadable should be active. * * In this case only when on the frontend, the post overview, post edit or new post admin page. * * @return array The conditionals. */ public static function get_conditionals() { return [ Primary_Category_Conditional::class ]; } /** * Registers a filter to change a post's primary category. * * @return void */ public function register_hooks() { \add_filter( 'post_link_category', [ $this, 'post_link_category' ], 10, 3 ); } /** * Filters post_link_category to change the category to the chosen category by the user. * * @param stdClass $category The category that is now used for the post link. * @param array|null $categories This parameter is not used. * @param WP_Post|null $post The post in question. * * @return array|object|WP_Error|null The category we want to use for the post link. */ public function post_link_category( $category, $categories = null, $post = null ) { $post = \get_post( $post ); if ( $post === null ) { return $category; } $primary_category = $this->get_primary_category( $post ); if ( $primary_category !== false && $primary_category !== $category->cat_ID ) { $category = \get_category( $primary_category ); } return $category; } /** * Get the id of the primary category. * * @codeCoverageIgnore It justs wraps a dependency. * * @param WP_Post $post The post in question. * * @return int Primary category id. */ protected function get_primary_category( $post ) { $primary_term = new WPSEO_Primary_Term( 'category', $post->ID ); return $primary_term->get_primary_term(); } } Submit