Expose Ninja Table data as JSON via REST API.

ninjatable-rest-api.php

<?php

/*
 * Code snippet to expose ninja table data as JSON via REST API
 * Example URL: https://yourdomain.com/wp-json/ninjatable/v1/table/#
 * In this working example you should enable authentication to protect your data
 * example is contained in `get_items_permissions_check`
 * Route logic sourced from https://developer.wordpress.org/rest-api/extending-the-rest-api/adding-custom-endpoints/
 */
add_action('rest_api_init', function () {
	$version = 1;
	$namespace = 'ninjatable/v' . $version;
	$base = 'table';

	register_rest_route( $namespace, '/' . $base, [
		'methods'  => WP_REST_Server::READABLE,
		'callback' => 'get_ninjatable_tables'
	  ]);

	register_rest_route( $namespace, '/' . $base . '/(?P<id>[\d]+)',
		[
		'methods'             => WP_REST_Server::READABLE,
		'callback'            => 'get_ninjatable_data',
		'permission_callback' => 'get_items_permissions_check',
	  ]);
	// add additional verb routes and capabilities via https://developer.wordpress.org/rest-api/extending-the-rest-api/adding-custom-endpoints/
});

/*
 * base route `ninjatable/v1/table` will load the available table list
 * recommend to project your results instead of exposing in this manner
 *
 * @param	WP_REST_Request		$request	The request object passed through the registered WordPress REST handler
 *
 */
function get_ninjatable_tables( WP_REST_Request $request ) {
	global $wpdb;
	$data = $wpdb->get_results( "SELECT ID, post_title AS name, post_status AS status FROM {$wpdb->posts} WHERE post_type = 'ninja-table'" );
	if ( ! empty( $data ) ) {
	  return new WP_REST_Response( $data, 200 );
	} else {
	  return new WP_Error( 'no_data', __( 'No tables found', 'text-domain' ), array( 'status' => 404 ) );
	}
}

/*
 * get table data route `ninjatable/v1/table/#` will load the available data from specfic table
 * recommend to project your results instead of exposing in this manner see use of `get_items_permissions_check`
 *
 * @param	WP_REST_Request		$request	The request object passed through the registered WordPress REST handler
 *
 */
function get_ninjatable_data( WP_REST_Request $request ) {
	
	$id = $request->get_param( 'id' );
	$data = ninjaTablesGetTablesDataByID($id);
	
	if ( !empty( $data ) ) {
	  return new WP_REST_Response( $data, 200 );
	} else {
	  return new WP_Error( 'no_data', __( 'No data was found matching your criteria', 'text-domain' ), array( 'status' => 404 ) );
	}
}

/*
 * `permission_callback` handler checks if the user can perform the action. This callback should 
 * return a boolean or a WP_Error instance. If this function returns true, the response will 
 * be processed. If it returns false, a default error message will be returned and the request 
 * will not proceed with processing. If it returns a WP_Error, that error will be returned 
 * to the client.
 *
 * @param	WP_REST_Request		$request	The request object passed through the registered WordPress REST handler
 *
 */
function get_items_permissions_check( WP_REST_Request $request ) {
	return true; // <--use to make readable by all
	return current_user_can( 'edit_something' );
}