Redirect if authenticated logic in Laravel's built-in auth?

High level answer: the purpose of RedirectIfAuthenticated is to keep an already authenticated user from reaching the login or registration routes/views since they're already logged in.

Test: bookmark the login view. Then login. Close the browser or window. Open the login bookmark. You'll go straight to user's home or where ever specified in RedirectIfAuthenticated.

For purposes of the LoginController, create a redirecTo() method, which is what the redirectPath() method looks for to see if you have customized the redirect.

// example
public function redirectTo()
{
    switch (auth()->user()->role) {
        case 'foo':
            return route('foo.home');

        case 'bar':
            return route('bar.home');

        default:
            auth()->logout();
            return route('web.welcome');
    }
}

You are not using the middleware correctly. This piece of code will fire everytime you send a request when you are logged in.

To change the redirect location after login you can override the redirectPath() method in your AuthController. (You can find the original method in vendor/laravel/framework/src/Illuminate/Foundation/Auth/RedirectsUsers.php)

This would look something like this:

...

public class AuthController extends Controller {

    ...

    public function redirectPath()
    {
        if(Auth::user()->sign_up_complete == 1) {
            return '/';
        } else {
            if(Auth::user()->step_one_complete == 0) {
                return '/register/step-1';
            } elseif(Auth::user()->step_two_complete == 0) {
                return '/register/step-2';
            } else {
                return '/';
            }
        }
    }


    // The rest of the class implementation.

}

Note: I've replaced the $this->auth() method with the Facade alternative (Auth::). Just because I am not sure if the AuthController has an auth() method.

Solution is in Mark Walet's answer, but need little correction. Return should be a string:

public class AuthController extends Controller {

    ...

    public function redirectPath()
    {
        if(Auth::user()->sign_up_complete == 1) {
            return '/';
        } else {
            if(Auth::user()->step_one_complete == 0) {
                return '/register/step-1';
            } elseif(Auth::user()->step_two_complete == 0) {
                return '/register/step-2';
            } else {
                return '/';
            }
        }
    }


    // The rest of the class implementation.

}