Magento – Is Google Content API for Shopping compatible with CE 1.9

I have developed an Google Shopping API v2 version based on the original Magento GoogleShopping module with some further improvements.

You can find it on GitHub: https://github.com/bluevisiontec/GoogleShoppingApi

It migrates the data from the original Magento GoogleShopping module. The only thing which is a bit more complicated is, that for OAuth2 a Google Developer Project hast to be created.

The blocks used in Rss creation are in app/code/core/Mage/Rss/Block

Just a guess, but maybe you want to modify the app/code/core/Mage/Rss/Block/Catalog/Category.php file? There are several, take a look at the blocks and see which affects the feed you are concerned with.

I would create a simple module that rewrites the block you need to modify. A quick example, assuming that your company is called Yourcompany :

app/code/local/Yourcompany/Rss/etc/config.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Yourcompany_Rss>
            <version>0.1.0</version>
        </Yourcompany_Rss>
    </modules>
    <global>
        <blocks>
            <yourcompany_rss>
                <class>Yourcompany_Rss_Block</class>
            </yourcompany_rss>
            <rss>
                <rewrite>
                    <catalog_category>Yourcompany_Rss_Block_Rss_Catalog_Category</catalog_category>
                </rewrite>
            </rss>
        </blocks>
        <helpers>
            <yourcompany_rss>
                <class>Yourcompany_Rss_Helper</class>
            </yourcompany_rss>
        </helpers>
    </global>
</config>

app/code/local/Yourcompany/Rss/Block/Rss/Catalog/Category.php

class Yourcompany_Rss_Block_Rss_Catalog_Category extends Mage_Rss_Block_Catalog_Category {

protected function _toHtml()
{
    $categoryId = $this->getRequest()->getParam('cid');
    $storeId = $this->_getStoreId();
    $rssObj = Mage::getModel('rss/rss');
    if ($categoryId) {
        $category = Mage::getModel('catalog/category')->load($categoryId);
        if ($category && $category->getId()) {
            $layer = Mage::getSingleton('catalog/layer')->setStore($storeId);
            //want to load all products no matter anchor or not
            $category->setIsAnchor(true);
            $newurl = $category->getUrl();
            $title = $category->getName();
            $data = array('title' => $title,
                'description' => $title,
                'link'        => $newurl,
                'charset'     => 'UTF-8',
            );

            $rssObj->_addHeader($data);

            $_collection = $category->getCollection();
            $_collection->addAttributeToSelect('url_key')
                ->addAttributeToSelect('name')
                ->addAttributeToSelect('is_anchor')
                ->addAttributeToFilter('is_active',1)
                ->addIdFilter($category->getChildren())
                ->load()
            ;
            $productCollection = Mage::getModel('catalog/product')->getCollection();

            $currentCategory = $layer->setCurrentCategory($category);
            $layer->prepareProductCollection($productCollection);
            $productCollection->addCountToCategories($_collection);

            $category->getProductCollection()->setStoreId($storeId);
            /*
            only load latest 50 products
            */
            $_productCollection = $currentCategory
                ->getProductCollection()
                ->addAttributeToSort('updated_at','desc')
                ->setVisibility(Mage::getSingleton('catalog/product_visibility')->getVisibleInCatalogIds())
                ->setCurPage(1)
                ->setPageSize(50)
            ;

            if ($_productCollection->getSize()>0) {
                $args = array('rssObj' => $rssObj);
                foreach ($_productCollection as $_product) {
                    $args['product'] = $_product;
                    $this->addNewItemXmlCallback($args);
                }
            }
        }
    }
    return $rssObj->createRssXml();
}

}

In this case, if you modify the collection at ~ line 47

$_productCollection = $currentCategory
                    ->getProductCollection()

to include the attributes you need you should have them in the feed.

You will also need your module declared in app/etc/modules, but your question was about rss, not custom modules ; )

So, take a look at the contents of app/code/core/Mage/Rss/Block/ , and rewrite the file that corresponds to your feed.

** I used a module name of Rss, that was totally arbitrary, you can name the module anything you want.