How to properly validate an invite when registering a user?

Question

Laravel

There is a registration controller with a method:

public function register(Request $request)
    {
        $this->validator($request->all())->validate();

        $invite_avaible = \App\Invite::isAvailable($request->input('invite'););

        if ($invite_avaible) {
          $user = $this->create($request->all());
        }

        return $this->registered($request, $user)
                        ?: redirect($this->redirectPath())->with('success', 'We have sent an activation link on your email id. Please verify your account.');
    }

In this method, the invite is also checked for existence and possibility of use:

$invite_avaible = \App\Invite::isAvailable($request->input('invite'));

The question is how to properly validate so that you can display your own error like: "Invite is not valid", "Invite does not exist"?
I study the documentation, it would be convenient to do this in the Validator, but as far as I understand, it is not very flexible in its settings.

Answer 1

it would be convenient to do this in the Validator, but as far as I understand, it is not very flexible in its configuration.

https://laravel.com/docs/5.6/validation#custom-val...
That is, you can use your own class that implements the interface Illuminate\Contracts\Validation\Rule,
you can use anonymous,
you can use extension