Cache works for html view but not for xml output

Question

I'm currently debugging (and trying to understand why) the caching for the html view is created, but not for the xml view.

I read the Joomla! documentation article https://docs.joomla.org/J3.x:Developing_an_MVC_Component/Adding_Cache and a similiar question in this portal 5 years ago: How can I use Joomla's Cache with my components view?

My controller.php looks like this:

public function display($cacheable = false, $urlparams = false)
{
    $cacheable = true;

    $viewName   = $this->input->get('view');
    $viewLayout = $this->input->get('layout', 'default');

    if (JFactory::getUser()->get('id') || !in_array($viewName, array('html', 'xml')) || $viewLayout == 'xsl') {
        $cacheable = false;
    }

    $document = JFactory::getDocument();
    $viewType = $document->getType();

    $view = $this->getView($viewName, $viewType, '', array('base_path' => $this->basePath, 'layout' => $viewLayout));

    $view->setModel($this->getModel('Sitemap'), true);

    $safeurlparams = array(
        'id' => 'INT',
        'itemid' => 'INT',
        'uid' => 'CMD',
        'action' => 'CMD',
        'property' => 'CMD',
        'value' => 'CMD',
        'view' => 'CMD',
        'lang' => 'CMD'
    );

    return parent::display($cacheable, $safeurlparams);
}

Folder structure:
components
- com_my_extension
--- views
---- html
---- xml

What I am missing here?

Is it that the standard Joomla! cache, doesn't cache the XML output and I have to do it manually?

Or is the data in $safeurlparams wrong? (I don't totally understand how the parts in this array should be.)

Answer 1

https://stackoverflow.com/questions/18448077/how-to-cache-a-php-generated-xml-file-in-joomla

An older question, but may give you a direction to consider to figure out what to add into the code generating your XML.