Update handle on a certain condition programatically

Follow below steps in order to update a handle on a certain event-

1. Create a observer on a events

In order to add handle to Magento’s layout update object before it’s too late, we have to observe controller_action_layout_load_before event.

<config>

    <frontend>

        <events>

            <controller_action_layout_load_before>

                <observers>

                    <observer_unique_name>

                        <class><Parckagename>_<Modulename>_Model_Observer</class>

                        <method>controllerActionLayoutLoadBefore</method>

                    </observer_unique_name>

                </observers>

            </controller_action_layout_load_before>

        </events>

    </frontend>

</config>

2. Create Observer

<?php

    class <Parckagename>_<Modulename>_Model_Observer

    {

        public function controllerActionLayoutLoadBefore(Varien_Event_Observer $observer)

        {

            /** @var $layout Mage_Core_Model_Layout */

            $layout = $observer->getEvent()->getLayout();

            $id = Mage::app()->getRequest()->getParam(‘id’);

            /* or */

            if(<write any condition> is true)

            {

                $layout->getUpdate()->addHandle(‘OUR_COOL_OBJECT_’.$id);

            }

            

        }

    }

That’s it!