Session and Input facades

You can use facades as well, no problem at all. Contracts and facades are the same imo. Both are interface you have to bind your final implementation to. Last but not least you can replace the input facade by form requests or plain Illuminate\Http\Request.

We have an episode about form requests here on Laracasts: https://laracasts.com/series/whats-new-in-laravel-5/episodes/3 as well as a good introduction by Matt Stauffer: http://mattstauffer.co/blog/laravel-5.0-form-requests

In addition to @bart's answer you can inject the session store in your controllers/methods like this:

use Illuminate\Routing\Controller;
use Symfony\Component\HttpFoundation\Session\SessionInterface as SessionContract;

class AwesomeController extends Controller {

    protected $session;

    public function __construct(SessionContract $session)
    {
        $this->session = $session;
    }

}

I hope this helps.