How do I create a Url object from the public file URI?

Question

How can a Url object be created from a file URI? Using the URI for a public file as a parameter for Url::fromUri() gives this error.

UnexpectedValueException: External URLs do not have internal route parameters. in Drupal\Core\Url->getRouteParameters().

$file = File::load($file_id);
$file_uri = $file->getFileUri();
$menu_link['url'] = Url::fromUri($file_uri);

Here is the class and method in question: https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Url.php/function/Url%3A%3AfromUri/8.2.x

Note that I don't need to get the actual URL in string format, I need to generate a Url object from the Url class that points to a file. This is because I am attempting to modify the path of a menu link and unfortunately that is not a simple matter of providing a URL string in Drupal 8.

This is the code I am using.

function teeprop_preprocess_menu__main(&$vars) {
  foreach($vars['items'] as $key => $menu_link) {
    if (!empty($menu_link['url']->getRouteParameters())) {
      $node_id = $menu_link['url']->getRouteParameters()['node'];
      $node_entity = Node::load($node_id);
      $node_type = $node_entity->getType();

      if ($node_type == 'pdf') {
        $file_id = $node_entity->get('field_pdf_file')->getValue()[0]['target_id'];
        $file = File::load($file_id);
//         $file_url = $file->url();
        $file_uri = $file->getFileUri();
        $vars['items'][$key]['url'] = Url::fromUri($file_uri, ['absolute' => TRUE]);
      }
    }
  }
}

Answer 1

I believe that the following should do what you need:

Url::fromUri(
  File::load(1)->url()
);

(I've tested this in a local 8.4.2 installation, and it yields a Url object that can be rendered without an error.)

The functions are admittedly named very misleadingly. Even though ::fromUri() sounds like it should accept the return value of ::getFileUri(), namely public://..., it actually only accepts internal:, base:, entity: and "external" URLs.

So you need to use ->url() to get the external URL of the file, and then pass that to ::fromUri().

Answer 2

$url = \Drupal::service('file_url_generator')->generate($file_uri);
$form['elements']['my_link'] = Drupal\Core\Link::fromTextAndUrl('Your_link_title', $url)->toRenderable();

You can also use other methods from Drupal\Core\File like generateAbsoluteString,

Answer 3

In Drupal 10

$file = File::load($file_id);
$vars['items'][$key]['url'] = $file->createFileUrl();

That will give you the relative URL as a string. Something like "/sites/default/files/my_file.pdf". If you want an absolute URL for some reason you can use $file->createFileUrl(FALSE).