set canonical URL in MODX

get_canonical.php

<?php
$context = $scriptProperties['context'] ?: 'ukltd';

//$context = (empty($scriptProperties['context'])) ? 'ukltd' : $scriptProperties['context'];

$linkedId = $modx->runSnippet('BabelTranslation', array(
    'contextKey' => $context,
    'resourceId' => $modx->resource->get('id')
));

$page = $modx->getObject('modResource', $linkedId);

$ctx = $modx->getContext($context);

$host = $ctx->getOption('http_host');

$linkedURL = 'http://' . $host .'/' . $page->get('uri') ;

$linkTag = "<link rel=\"canonical\" href=\"$linkedURL\"/>";
$modx->regClientStartupHTMLBlock($linkTag);

return '';