How can I add HTML links in e-mails?

Question

          $content_title = $translated_entity->getTitle();
          $url_alias = \Drupal::service('pathauto.alias_cleaner')
            ->cleanString($content_title);
          $content_link = <<<link
    <a href='/publications/$url_alias'>$url_alias</a>
    link;
          $params['node_title'] = 'Chaire ANMT – Nouvelle Publication : ' . $entity->label() . '';
          $params['message'] = <<<msg
    Nouvelle publication : $content_title $content_link. \n
    msg;
//some code
  $result = $mailManager->mail($module, $key, $subscriber, $langcode, $params, null, $send);

The email generated do not place the link next to the content title. How to fix that?

Answer 1

That is expected, when the Drupal mail back-end that comes with Drupal, implemented by the PhpMail class, is used. In fact, its format() method contains the following code.

  // Join the body array into one string.
  $message['body'] = implode("\n\n", $message['body']);

  // Convert any HTML to plain-text.
  $message['body'] = MailFormatHelper::htmlToText($message['body']);

  // Wrap the mail body for sending.
  $message['body'] = MailFormatHelper::wrapMail($message['body']);

MailFormatHelper::htmlToText() is the method that changes the HTML markup as you see.

The only way to avoid that is to use a different mail back-end or implement one in a custom module.