Extension Rewrites a Model Method to Rewrite a Resource Model Method: How to Extend It?

Question

I have ThirdPary_Extension that rewrites a resource class method of Mage_Catalog_Model_Resource_Product_Indexer_Price. However, ThirdPary_Extension goes about doing this a little strange. It's configured to rewrite only Mage_Catalog_Model_Product_Indexer_Price, but in this class' _construct(), it's pointing to a resource class that extends off of Mage_Catalog_Model_Resource_Product_Indexer_Price.

Let me illustrate.

config.xml

...
<models>
     <catalog>
        <rewrite>
            <product_indexer_price>ThirdParty_Extension_Model_Product_Indexer_Price</product_indexer_price>
        </rewrite>
    </catalog>
</models>
...

ThirdParty_Extension_Model_Product_Indexer_Price

class ThirdParty_Extension_Model_Product_Indexer_Price extends Mage_Catalog_Model_Product_Indexer_Price
{
    protected function _construct()
    {
        $this->_init('thirdparty/resource_product_indexer_price');
    }
    ...       
}

ThirdParty_Extension_Model_Resource_Product_Indexer_Price

class ThirdParty_Extension_Model_Resource_Product_Indexer_Price extends Mage_Catalog_Model_Resource_Product_Indexer_Price
{
    protected function _rewrittenMethod()
    {
        // Good stuff
    }
    ...       
}

And in Mage_Catalog_Model_Product_Indexer_Price::reindexAll, you have $this->_getResource()->reindexAll(), which invokes the rewritten method as was intended.

However, this causes some issues. Depending on how you're instantiating the resource model and invoke a method, you may end up with using ThirdParty_Extension_Model_Resource_Product_Indexer_Price (good) or Mage_Catalog_Model_Resource_Product_Indexer_Price (bad), among one or two other things. Obvisouly, the extension works for re-indexing prices, but I'm not a fan of how it's done. Please correct me if I misunderstand this extension.

Now the question, how do I rewrite Mage_Catalog_Model_Resource_Product_Indexer_Price the right (lol!) way?

1. Rewrite both Mage_Catalog_Model_Product_Indexer_Price and Mage_Catalog_Model_Resource_Product_Indexer_Price to re-align everything nicely? Or..

2. Rewrite just ThirdParty_Extension_Model_Resource_Product_Indexer_Price

Option #1 would typically be my pick, but I'm thinking maybe there was a reason this rewrite was done in such a way, in which case #2 would be the way to go. What say ye?

Answer 1

You can also rewrite resource models.

    <models>
        <catalog_resource>
            <rewrite>
                <product_indexer_price>ThirdParty_Extension_Model_Resource_Product_Indexer_Price</product_indexer_price>
            </rewrite>
        </catalog_resource>

Way to go

I'm always looking to do as less rewrites as possible. So:

• is there a event fired I can use, use it!
• how can I rewrite with as less impact as possible to avoid module conflicts or problems in future upgrades!

So, I would only rewrite the resource, because that's the less impact I can do.