MODX ID to JSON

MODX ID to JSON

<?php
header("Content-Type:application/json");

$id = $_GET["id"];
if(empty($id)){ die(); }

$obj = $modx->getObject('modResource', $id);

$output = [];

$output = array(
    "name" => $obj->get('longtitle'),
    "sku" => $obj->getTVValue('sku'),
    "img" => $obj->getTVValue('product_img'),
    "barrel_length" => $obj->getTVValue('barrel-length')
);

return $modx->toJson($output);