3

In drupal 8, how do you load the node object in hook_preprocess_page() when on the node preview page?

I had a bug come up where this standard way of loading the current node object was failing on the preview page:

$node = \Drupal::routeMatch()->getParameter('node');
6

If you need to use the node object in hook_preprocess_page() on the preview page, you need to use the "node_preview" parameter, instead of the "node" parameter:

function mymodule_preprocess_page(&$vars) {

  $route_name = \Drupal::routeMatch()->getRouteName();

  if ($route_name == 'entity.node.canonical') {
    $node = \Drupal::routeMatch()->getParameter('node');
  }
  elseif ($route_name == 'entity.node.preview') {
    $node = \Drupal::routeMatch()->getParameter('node_preview');
  }
  • I was wondering about the preview node for at least a year! Is parameter node_preview something new? – Philipp Michael Oct 17 '17 at 9:34
  • 1
    It's loaded from tempStoreFactory, since the node object wouldn't exist in preview. So it saves it as a separate object with a uuid, that is then retrieved on the preview page. It's annoying that the variable name is different, but it's a signal that it's not a real node. So things like $node_preview->url() won't work. I'm going to have to fix some bugs related to that in my current project. See nodeForm::preview() for the code that saves the node object and redirects. – oknate Oct 17 '17 at 14:17

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