Trying get dynamic content hole-punched through Magento's Full Page Cache - caching

Question

I am using Magento Enterprise 1.10.1.1 and need to get some dynamic content on our product pages. I am inserting the current time in a block to quickly see if it is working, but can't seem to get through full page cache.
I have tried a variety of implementations found here:
http://tweetorials.tumblr.com/post/10160075026/ee-full-page-cache-hole-punching
http://oggettoweb.com/blog/customizations-compatible-magento-full-page-cache/
http://magentophp.blogspot.com/2011/02/magento-enterprise-full-page-caching.html
Any solutions, thoughts, comments, advice is welcome.
here is my code:
app/code/local/Fido/Example/etc/config.xml
<?xml version="1.0"?>
<config>
<modules>
<Fido_Example>
<version>0.1.0</version>
</Fido_Example>
</modules>
<global>
<blocks>
<fido_example>
<class>Fido_Example_Block</class>
</fido_example>
</blocks>
</global>
</config>
app/code/local/Fido/Example/etc/cache.xml
<?xml version="1.0" encoding="UTF-8"?>
<config>
<placeholders>
<fido_example>
<block>fido_example/view</block>
<name>example</name>
<placeholder>CACHE_TEST</placeholder>
<container>Fido_Example_Model_Container_Cachetest</container>
<cache_lifetime>86400</cache_lifetime>
</fido_example>
</placeholders>
</config>
app/code/local/Fido/Example/Block/View.php
<?php
class Fido_Example_Block_View extends Mage_Core_Block_Template
{
private $message;
private $att;
protected function createMessage($msg) {
$this->message = $msg;
}
public function receiveMessage() {
if($this->message != '') {
return $this->message;
}
else {
$this->createMessage('Hello World');
return $this->message;
}
}
protected function _toHtml() {
$html = parent::_toHtml();
if($this->att = $this->getMyCustom() && $this->getMyCustom() != '') {
$html .= '<br />'.$this->att;
}
else {
$now = date('m-d-Y h:i:s A');
$html .= $now;
$html .= '<br />' ;
}
return $html;
}
}
app/code/local/Fido/Example/Model/Container/Cachetest.php
<?php
class Fido_Example_Model_Container_Cachetest extends Enterprise_PageCache_Model_Container_Abstract {
protected function _getCacheId()
{
return 'HOMEPAGE_PRODUCTS' . md5($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 $block->toHtml();
}
protected function _saveCache($data, $id, $tags = array(), $lifetime = null) { return false; }
}
app/design/frontend/enterprise/[mytheme]/template/example/view.phtml
<?php echo $this->receiveMessage() ?>
snippet from app/design/frontend/enterprise/[mytheme]/layout/catalog.xml
<reference name="content">
<block type="catalog/product_view" name="product.info" template="catalog/product/view.phtml">
<block type="fido_example/view" name="product.info.example" as="example" template="example/view.phtml" />

Answer 1

The <name> in the cache.xml must match your blocks full name in the layout, not the alias, e.g. <name>product.info.example</name>
Also, _getIdentifier() isn't implemented on Enterprise_PageCache_Model_Container_Abstract, just remove it from the string returned by your _getCacheId().
If you need to add some variants, implement _getIdentifier() to return a session id or whatever you need.