vue-wp/plugins/cia-endpoints/includes/class.make-search.php

<?php
// include('formats.php');

class Make_Search_Endpoint extends WP_REST_Controller {
    /**
     * Register the routes for the objects of the controller.
     */
    public function register_custom_route($route) {
        $version = '2';
        $namespace = 'craft/v' . $version;

        register_rest_route( $namespace, '/' . $route, [
            array(
                'methods'  => WP_REST_Server::READABLE,
                'callback' => array( $this, 'get_all_items' )
            ),
        ]);
    }
    public function get_all_items( $request ) {
        $args = array(
            'numberposts' => 9,
        );
        $params = $request->get_params();
        if($params['s']) {
            $args['s'] = $params['s'];
        }
        // https://www.relevanssi.com/user-manual/functions/relevanssi_do_query/
        $q = new WP_Query( $args );
        relevanssi_do_query( $q );
        $found_posts = $q->get_posts();
        
        return new WP_REST_Response( $found_posts, 200 );
    }
}

?>