Add a block to a page with event observer

Question

I'm trying to add a static block to a page with an observer. The event that I'm listening to is controller_action_layout_generate_blocks_after and this is my observer code:

<?php
...
class Antonino_Banner_Model_Observer
{
 public function showBannerWhenLoad(Varien_Event_Observer $observer) 
 {
 $layout = Mage::app()->getLayout();
 $pageId = Mage::app()->getRequest()->getParam('id');
 $selectedCatId = Mage::getStoreConfig('antoninobanner/general/choose_category');
 if ($pageId==$selectedCatId){
 Mage::log('Bingo! PageId= '. $pageId.' SelectedId= '.$selectedCatId);
 $messageBlock = $layout->createBlock('cms/block')->setBlockId('antonino_banner');
 $breadcrumbs = $layout->getBlock('breadcrumbs');
 $breadcrumbs->append($messageBlock);
 }/*else{
 Mage::log('Oh no! The ids do not match');
 }*/
 }
}

The event is regularly triggered and in the system.log I can read the "Bingo!..." string. But on the page, the 'antonino_banner' block is not added. Naturally, I've created a static block in admin->static blocks.

Any help will be appreciated, thanks.

• Piyush: Make sure breadcrumbs block is there on the page as you are appending your block to it
• Marco Antonino: Thank you for your answer. Yes, the breadcrumbs block is on the page because if I write var_dump(Mage::app()->getLayout()), when I reload the page, in the protected '_blocks' array there is the following element 'breadcrumbs' => object(Mage_Page_Block_Html_Breadcrumbs)[199]

Answer 1

Ok, I think could handle this, but I'm not very satisfied by the result. I'm listening to

core_block_abstract_to_html_after

And my Observer code is:

<?php 
class Antonino_Banner_Model_Observer
{
 public function showBannerWhenLoad(Varien_Event_Observer $observer) {
 $pageId = Mage::app()->getRequest()->getParam('id');
 $selectedCatId = Mage::getStoreConfig('antoninobanner/general/choose_category');
 if ($pageId==$selectedCatId){
 $block = $observer->getBlock();
 if($block->getNameInLayout() == 'breadcrumbs')
 {
 $transport = $observer->getTransport();
 $html = $transport->getHtml();
 $html .= '<h1>We need to append something here</h1>';
 $transport->setHtml($html);
 }
 }/*else{
 Mage::log('Oh no! The ids do not match');
 }*/
 }
}

I don't like this solution very much because this means I must write some raw HTML code directly in this page...

Answer 2

I think that your are not using a good event, it's a little late and the layout is already rendered, try to use these :

• controller_action_layout_load_before
• controller_action_layout_generate_blocks_before

Edit:

Try this one: core_block_abstract_prepare_layout_before

Reference

• Marco Antonino: Thank you for your answer. Unfortunatly both the events that you suggested appen too soon: the blocks are not still loaded. In fact I get this error: Call to a member function append() on boolean . I think this means that magento still doesn't know the name of the blocks.
• PЯINCƎ: Or, he don't find a breadcrumbs block, please try the footer $layout->getBlock('footer'), try also this event core_block_abstract_prepare_layout_before
• Marco Antonino: With those changes I've got the following error: Fatal error: Maximum function nesting level of '256' reached, aborting!