Holepunching of header in magento store

Question

I have implemented holepunching of header in magento, and even though I have got it working on a per customer basis, I need the ability to take this one level deeper by making it work on diff cart item counts too.

Here is my code.

class AD_PageCache_Model_Container_Header extends Enterprise_PageCache_Model_Container_Abstract {

    protected function _getIdentifier() {
        return $this->_getCookieValue(Enterprise_PageCache_Model_Cookie::COOKIE_CUSTOMER, '');
    }

    // public function getCacheKeyInfo() {
    //  $info = parent::getCacheKeyInfo();
    //  die('boo');
    //  $info['cart_count'] = Mage::helper( 'checkout/cart' )->getCart()->getItemsCount();

    //  return $info;
    // }

    protected function _getCacheId() {
        //return 'CONTAINER_HEADER_' . md5($this->_placeholder->getAttribute('cache_id') . $this->_placeholder->getAttribute('cart_count') ) . '_' . $this->_getIdentifier();
        return 'CONTAINER_HEADER_' . md5( $this->_placeholder->getAttribute('cache_id') . $this->_getIdentifier() );
    }

    protected function _renderBlock() {
        $blockClass = $this->_placeholder->getAttribute('block');
        $template = $this->_placeholder->getAttribute('template');

        $block = new $blockClass;
        $block->setTemplate($template);
        return $block->toHtml();
    }

}

My understanding from what I have been reading from holepunching threads on Magento is that Mage app is not initialized when FPC cache is serving the request, so basically the method of adding a placeholder attribute can't work, since Mage::helper( 'checkout/cart' )->getCart()->getItemsCount(); won't work, right?

And even though how is that it should be, but it didn't seem to run at all, like I placed a die() call in there but nothing happened.

So what I am missing? And how can I retrieve the cart items count so that it can be used to build the cache ID?

Progress: I found Enterprise_PageCache_Model_Cookie::COOKIE_CART but this changes only once upon cart updation. After that it stays same. This is weird, this feels like the solution but its behavior says otherwise.

I couldn't find cart items count in session either. So the only way I currently see to do this would be to save the cart quantity in session whenever it updates and then use that in _getIdentifier().

I found that observers are inconsistent for cart. For addition, updation the events are dispatched but for removal, it doesn't. So I guess I can add my observer to price updation of the quote somehow, if that is consistent in having observers?

Any suggestions?

Maybe I don't understand what is your problem exactly. At first you should return needed data from your block getCacheKeyInfo() method and then in _getCacheId() of your placeholder class build unique key (i.e. container individual cache id). — Dmytro Zavalkin

Zifius Zifius · Accepted Answer · 2013-01-17T22:04:41

See my similar question: Full Page Cache invalidation on cart (quote) change

I gave up on implementing because it wasn't possible in my case, but I'd dig into Enterprise_PageCache_Model_Container_Advanced_Quote further as it seems to be used by cart block to refresh itself in case of quote contents change

Holepunching of header in magento store

2 Answers