MODX snippet: finds all resources with a specified template and writes a list of ids

findTemplateID

<?php
$c = $modx->newQuery('modResource');
$resIds = array();
/* we only want published and undeleted resources */
$c->where(array(
  'published' => true,
  'deleted' => false,
  'template'=>$templateID
));
$resources = $modx->getCollection('modResource',$c);
foreach ($resources as $resource) {
    $resourceArray=$resource->toArray();
    $resIds[]=$resourceArray['id'];
};
$resIds = array_values(array_unique($resIds));  // remove duplicated ids
//var_dump($resIds);
$lstIds = implode(',',$resIds);
return $lstIds;