<?php

// -- modules/controllers/TestController.php --

namespace modules\controllers;

use craft\base\Element;
use craft\web\Controller;

class TestController extends Controller
{
    public function actionTest(int $elementId, int $siteId)
    {
        // Do this if you want to protect the preview target from public access:
        $this->requireAuthorization('customAuthorizationKey:' . $elementId);

        /** @var Element $element */
        $element = \Craft::$app->getElements()->getElementById($elementId, null, $siteId);
        return $this->asRaw($element->title);
    }
}