function render()
 {
     if (!($templateName = $this->RenderTemplate)) {
         $templateName = 'SimpleNewsletterTemplate';
     }
     // Block stylesheets and JS that are not required (email templates should have inline CSS/JS)
     Requirements::clear();
     // Create recipient with some test data
     $recipient = new Recipient(Recipient::$test_data);
     $newsletterEmail = new NewsletterEmail($this, $recipient, true);
     return HTTP::absoluteURLs($newsletterEmail->getData()->renderWith($templateName));
 }
 /**
  * Preview a {@link Newsletter} draft.
  *
  * @param SS_HTTPRequest $request Request parameters
  */
 public function preview($request)
 {
     $newsletterID = (int) $request->param('ID');
     $newsletter = DataObject::get_by_id('Newsletter', $newsletterID);
     $templateName = $newsletter && $newsletter->Parent()->Template ? $newsletter->Parent()->Template : 'GenericEmail';
     // Block stylesheets and JS that are not required (email templates should have inline CSS/JS)
     Requirements::clear();
     $email = new NewsletterEmail($newsletter);
     return HTTP::absoluteURLs($email->getData()->renderWith($templateName));
 }