How to get the raw value of the url in a link field

Question

I'm doing this:

$link = $node->field_link->first();
if ($link) {
  $url = $link->getUrl()->toString();
  ...
}

If the value in the link field is /node/123 but there is a URL alias defined as:

Alias: /about-us    System path: /node/123

I get /about-us in $url. I want to get /node/123.

How do I get the raw url value instead of the aliased value?

Answer 1

Instead of rendering the URL object with toString() use the method Url::getInternalPath:

$url = $link->getUrl();
if ($url->isRouted()) {
  $path = $url->getInternalPath();
}

Answer 2

Another solution I happened upon since I first posted is

$uri = $node->get('field_link')->uri;

The difference between this and the accepted answer is that this approach gives the actual, raw value in the link field (with 'internal:' appended to the front) whatever it is, without URL alias translation. The accepted answer doesn't translate /node/123 in the field to /about-us, but it does translate /about-us in the field to /node/123.

Once $uri has been modified as needed, it can be put back into the node by

$node->set('field_link', ['uri' => $uri]);