A couple of weeks ago I experienced a Magento URL rewrite behaviour which I wasn’t aware of. Considering that I work with Magento since 2010, I decided to write about it.
Pick a clean Magento installation (tested on CE v.1.9.1.1 but I think it’s the same for other versions even for EE) and create 2 simple products both with the same name “Test Product”. In this way these products should also have the same URL Key “test-product”. Be sure that these products are enabled and visibile so relative URL rewrite will be generated. Then, go to URL Rewrite Management admin section and you’ll see this:
Ok, that’s normal: 2 products 2 related URL rewrites. Now simply execute URL Rewrite reindex process and check URL Rewrite Management again, you’ll see this:
WTF?!? The product with ID 2 now has changed the canonical URL from test-product-2.html to test-product-3.html (test-product-2.html now will generate a 301 redirect to test-product-3.html). Let’s try to repeat reindex process again, you’ll see:
Oh-oh… Now the product with ID 2 has “test-product-4.html” as canonical URL! Again, “test-product-2.html” and “test-product-3.html” are now 301 redirects to “test-product-4.html”.
Yes, it’s true: Magento, for products with the same URL key, keeps generating URL rewrites again and again as an effect of URL rewrite reindex process.
This behaviour is described in this answer by Matthias Zeis on Magento Stack Exchange: http://magento.stackexchange.com/questions/18186/understanding-catalog-url-rewrite-indexer/18329#18329.
On the same thread there is a code solution to this problem which involves patching the core by changing the Mage_Catalog_Model_Url class.
At method getProductRequestPath, around line 809, remove the $product->getUrlKey() == '' check. So this:
/**
* Get unique product request path
*
* @param Varien_Object $product
* @param Varien_Object $category
* @return string
*/
public function getProductRequestPath($product, $category)
{
// [...]
/**
* Check if existing request past can be used
*/
if ($product->getUrlKey() == '' && !empty($requestPath)
&& strpos($existingRequestPath, $requestPath) === 0
) {
$existingRequestPath = preg_replace(
'/^' . preg_quote($requestPath, '/') . '/', '', $existingRequestPath
);
if (preg_match('#^-([0-9]+)$#i', $existingRequestPath)) {
return $this->_rewrites[$idPath]->getRequestPath();
}
}
// [...]
}
Has to be changed into this:
/**
* Get unique product request path
*
* @param Varien_Object $product
* @param Varien_Object $category
* @return string
*/
public function getProductRequestPath($product, $category)
{
// [...]
/**
* Check if existing request past can be used
*/
if (!empty($requestPath)
&& strpos($existingRequestPath, $requestPath) === 0
) {
$existingRequestPath = preg_replace(
'/^' . preg_quote($requestPath, '/') . '/', '', $existingRequestPath
);
if (preg_match('#^-([0-9]+)$#i', $existingRequestPath)) {
return $this->_rewrites[$idPath]->getRequestPath();
}
}
// [...]
}
This solution works but I think that is better to not change the core, even with a monkey patch. If possible try to have different URL keys for all products so you don’t need this.
Posted with : Magento, What The F..k Moment