i want rewrite magento helper core class Mage_Core_Helper_Data. I have try below code, but it is not working

<?xml version="1.0" ?>

Can any one tell why is not working?

  • can any one tell why i got down vote on this question
    – Amit Bera
    Jan 16, 2015 at 12:27

1 Answer 1


When you rewrite a helper class, it will only take effect when you use Mage::helper('...').

However, most helper classes extend from Mage_Core_Helper_Data directly and then, the original class is used :(

For example:

class My_Custom_Helper_Class extends Mage_Core_Helper_Data {

If you want to rewrite such a class in all cases, you can use the ugly method to copy it into app/code/local/Mage/Core/Helper/Data.php and do your edits there.

It is not nice style, but if you want to extend a class very high up in the hierarchy, you have no other choice as far as I know.

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