Redirect to home page without using deprecated methods

Question

I am attempting to add some code to a hook_entity_view_alter() function to redirect the user to the homepage under a rare condition with RedirectResponse.

I understand the method to accomplish this is along these lines (taken from here):

$response = new Symfony\Component\HttpFoundation\RedirectResponse($url);
$response->send(); // don't send the response yourself inside controller and form.
return;

My issue is that I am not sure how to format $url. Most articles on the topic, such as this one, suggest using \Drupal::url(), but this is deprecated in favour of Drupal\Core\Url. I would like to avoid using deprecated methods as much as possible, but am stuck at trying to figure out what the Drupal\Core\Url equivalent is to \Drupal::url('<front>'). I am not sure which methods to be using, and nothing I've tried with Url::fromUri() has worked.

Answer 1

Try using Url::fromInternalUri then instead of fromUri():

https://api.drupal.org/api/drupal/core!lib!Drupal!Core!Url.php/function/Url%3A%3AfromInternalUri/8.2.x

It specifically notes the use of front and none. But you can't pass the URL object or path tokens to RedirectResponse, as this is a Drupal construct. That class expects the following arguments:

http://api.symfony.com/2.3/Symfony/Component/HttpFoundation/RedirectResponse.html

string  $url        The URL to redirect to
integer $status     The response status code
array   $headers    An array of response headers

$url needs to be a string, so on your URL object, call ->toString() to get the URL.

https://api.drupal.org/api/drupal/core%21lib%21Drupal%21Core%21Url.php/function/Url%3A%3AtoString/8.2.x