Magento - How can I disable cache for widget or block

Question

I need some help on caching issue in CMS block.

I have developed a new product slider for store front that displays latest products in the home page this works great when cache is disabled but when i enable the cache add to cart button is not working, as all the formkey is cached in the block. (P.s. Magento FPC and compilation are enabled)

The widget config as:

{{widget type="catalog/product_widget_new" display_type="all_products" show_pager="1" products_per_page="5000" products_count="5000" template="catalog/product/widget/new/content/new_grid.phtml"}}

Then I include it in the home page like:

<block type="wrapper" name="section.no1">
    <action method="setContainer">
        <container>1</container>
    </action>
    <block type="cms/block" name="best_deals" >
    <action method="setParams">
        <params>class="best_deals"</params>
    </action>
    <action method="setBlockId">
            <block_id>best_deals</block_id>
        </action>
</block>

I have tried..

<action method="setCacheLifetime"><s>0</s></action>

and

<action method="setCacheLifetime"><s>null</s></action>

even..

<action method="unsetData"><key>cache_lifetime</key></action>
<action method="unsetData"><key>cache_tags</key></action>

None of them take effect. Perhaps I'm missing something?

Update: I solved the issue by adding $this->setCacheKey(uniqid()); to my template file.

Answer 1

You can try in homepage template directly

echo $this->getLayout()->createBlock('cms/block')->setBlockId('block_id')->setCacheKey(uniqid())->toHtml();

Answer 2

Fabrizio has a real good write up on why this isn't working for you. Turns out that in XML, when you pass null or even 0 that still counts as a value and not actually null.

http://fbrnc.net/blog/2015/06/cache-and-layout-xml-tricks

His article will explain it better, but I have had the most success with:

class My_Module_Helper_Data extends Mage_Core_Helper_Abstract {

    public function returnNull() 
    {
        return null;
    } 
}

and

<reference name="footer">
    <action method="setCacheLifetime"><lifetime helper="mymodule/returnNull" /></action>
</reference>