Get node in custom token to be used in Pathauto url alias pattern

Question

I'm attempting to use a custom made token for url alias patterns. I've been able to custom tokens using node information just fine. But it just occurred to me that I don't know how I could possibly use it with url alias patterns.

function mymodule_plugins_tokens($type, $tokens, array $data, array $options, \Drupal\Core\Render\BubbleableMetadata $bubbleable_metadata){
  $token_service = \Drupal::token();
  $replacements = array();
  if($type == 'mymodule_tokens') {
    foreach($tokens as $name => $original){
      switch($name){
        case 'current_nid':
        $node = \Drupal::routeMatch()->getParameter('node');
        $title = (!empty($node)) ? $node->id() : 'This is a test'; 
        $replacements[$original] = $title;
        break;
      }
    }
  }
  return $replacements;
}

It works fine if I'm using it on a node page. But what if I want to use it in a url alias pattern in the pathauto module?

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

I know here it gets the node based on the current page it's on. But if it's used in a url alias pattern it's not on any page at the time of url alias construction. I have a feeling this is possible since there are already tokens like [node:title] that work. Also is there any weird thing I can do like this?

[mymodule_tokens:current_nid[node:nid]]

Where I pass a token within a token? And if I can how would I access that extra parameter within my custom token. (p.s. I understand that my example is just getting the current_nid and that there are already tokens for it. I'm just using that as an example)

Is there anyway I can get the node from my custom token to be used in a url alias pattern?

Answer 1

You get the node from $data:

  if (!empty($data['node'])) {
    /* @var \Drupal\node\NodeInterface $node */
    $node = $data['node'];
  }

It is the responsibility of the code which calls replace() to provide the correct context (in case of Pathauto the node for which it's building the alias).