What methods to replace in helper for Compare Products

Question

I am trying to replace the helper that provides the compare box with the list of products added to it. My helper is going to get the product ids from a cookie instead of from Magentos session.

My own class in app/code/local/Mynamespace/Mymodule/Helper/Data.php extends Mage_Core_Helper_Abstract.

When looking at list.phtml and sidebar.phtml in app/design/frontend/base/default/template/catalog/product/compare/ they seem to be calling different methods when getting the compare products collection. sidebar.phtml seems to be calling Mage_Catalog_Block_Product_Compare_Sidebar->helper('catalog/product_compare')->getItemCollection() and list.phtml seems to be calling Mage_Catalog_Block_Product_Compare_List->getItems().

What method(s) do I need to be replacing and in what classes are they present?

Answer 1

As there is code duplication between the two core methods for retrieving/building the compare collection (refs here and here), I would suggest that you do the following:

1. Rewrite Mage_Catalog_Helper_Product_Compare, overriding its getItemCollection() method
2. Rewrite the Mage_Catalog_Block_Product_Compare_List and block's getItems() method to simply return the product compare helper's overridden getItemsCollection() method.

Rewrite XPATHs are global/helpers/catalog/rewrite/product_compare and global/blocks/catalog/rewrite/compare_list respectively.