<?php
namespace app\controller;
use support\Request;
class Index2
{
    public function index(Request $request)
    {
        $request->session()->set('rand', rand(1000, 9999));
        return response('set');
    }
}

<?php
namespace app\controller;
use support\Request;
class Index
{
    public function index(Request $request)
    {
        return response($request->session()->get('rand'));
    }
}