Need tips about authentication check (cookies)

What is the most common and robust auth check pattern in CI?

I personally see two ways:

1) insert check routine into a hook-function ('pre_controller' or 'post_controller_constructor' ?) - one for all controllers - nice
2) write it in __construct() directly, but it forces to duplicate code a lot, for each controller. bad..

I tried 1st way but got this:

PHP Code:

$hook['pre_controller'] = function ()
{
    $id = $this->input->cookie('user_id'); // ERROR: Undefined property: CI_Hooks::$input
    // ...
}; 


It seems that $this->input is absent in function's scope. Maybe I should create standalone class? or entirely different approach?

Please nudge me in a right direction.