Dynamically insert into layout xml of Magento - magento

Question

Im a newbie at Magento. Im trying to build a module which dynamically inserts code xml into layout xml before its rendered -
something similar to how CMS>pages have been build.
Just like how we can specify layout xml in the design section of a page (admin > cms > page), I would like to insert into layout.xml through my module.
Basically, I would like to
have an admin section from where I can enter layout code through a
form and store in database - I have figured out this part
have Magento pull these pieces of code stored in the database and create an xml file before the layout files are aggregated and interpreted. - Im unable to build this portion.
Any help would be appreciated.

Answer 1

Just a little enlightment
You can add those layout xml by using observer,
Let's say you want those layout xml added before the xml is generated
We can use event controller_action_layout_generate_xml_before
Here's the sample code (in config.xml)
<frontend>
<events>
<controller_action_layout_generate_xml_before>
<observers>
<add_new_layout>
<class>test/observer</class>
<method>addNewLayout</method>
</add_new_layout>
</observers>
</controller_action_layout_generate_xml_before>
</events>
</frontend>
Here's the Observer.php
public function addNewLayout($observer){
$layout = $observer->getEvent()->getLayout();
$update = $layout->getUpdate();
//$action = $observer->getEvent()->getAction();
//$fullActionName = $action->getFullActionName();
//in case you're going to add some conditional (apply these new layout xml on these action or other things, you can modify it by yourself)
//here is the pieces of layout xml you're going to load (you get it from database)
$xml = "<reference name='root'><remove name='footer'></remove></reference>";
$update->addUpdate($xml);
return;
}

Answer 2

Another posibility is to use the core_layout_update_updates_get_after-event and a placeholder (non-existing) layout xml:
<frontend>
<layout>
<updates>
<foobar>
<file>foo/bar.xml</file>
</foobar>
</updates>
</layout>
<events>
<core_layout_update_updates_get_after>
<observers>
<foobar>
<type>singleton</type>
<class>foobar/observer</class>
<method>coreLayoutUpdateUpdatesGetAfter</method>
</foobar>
</observers>
</core_layout_update_updates_get_after>
</events>
</frontend>
Example PHP in your observer:
/**
* Event dispatched when loading the layout
* #param Varien_Event_Observer $observer
*/
public function coreLayoutUpdateUpdatesGetAfter($observer)
{
/** #var Mage_Core_Model_Config_Element $updates */
if (Mage::getStoreConfig('foobar/general/enabled')) {
$file = Mage::getStoreConfig('foobar/general/layout_xml');
if (!empty($file)) {
$updates = $observer->getUpdates();
if ($updates->foobar) {
$updates->foobar->file = $file;
}
}
}
}