Where place render page code?

What is the most convenient method

for example, in the controller

Code:

<code>function action_index(){

$my_var = "test";

$this-&gt;template-&gt;my_var = $my_var;

$this-&gt;template-&gt;render();

}
</code>

or in the model
<code>class Model_my_model extends Model{

function my_model(){

$my_var = "test";

$this-&gt;template-&gt;my_var = $my_var;

$this-&gt;template-&gt;render();

}

}
</code>

A:

You could create a base controller with the common code and extend it in the other controllers.

Code:

<code>class Controller_Base extends Controller
{
    public function before()
    {
        parent::before();

        // do common stuff here
        $my_var = "test";
        $this-&gt;template-&gt;my_var = $my_var;
    }
}