When I log in, how do I get the user back to the pre-login interview? How to give value to others?

I have a problem now
when a user clicks on a link and goes to the login window, I will add his previous address, such as

, to the web address.

https://ha.xyz.com/signin?request=https://ha.xyz.com/products/121111

and then log in to the noodle shop, which will allow the user to choose whether to log in or EMAIL login
, so the click on the link will be

https://www.facebook.com/v3.0/dialog/oauth?client_id=xxx&state=aaa&response_type=code&sdk=php-sdk-5.6.2&redirect_uri=https%3A%2F%2Fha.xyz.com%2F%2Fvendor%2Fsdk%2Ffacebook%2Flogin-callback.php&scope=email

the generation of this connection is the oauth of facebook

require_once "/vendor/autoload.php";

  $fb = new Facebook\Facebook([
  "app_id" => "xxx",
  "app_secret" => "aaa",
  "default_graph_version" => "v3.0",
  ]);

  $helper = $fb->getRedirectLoginHelper();

  $permissions = ["email"];

$loginUrl = $helper->getLoginUrl("".$host_url."/vendor/sdk/facebook/login-callback.php", $permissions);

the question is how can I give him request ?
he $loginUrl generates an address structure that cannot be plugged into
at all, and the existence of $_ GET ["request"] can be determined only after login-callback.php authentication is successful!