event dispatch before rendering 404 page of "file not found" - magento

Question

my intention is simple i just want to get my pages in different formats
e.g
www.my-site.com/product-name.html -- will load the page in html
but i want a json object when i type
www.my-site.com/product-name.json
if their is any event that magneto dispatch before rendering 404 page, that can be very helpful
or i have to rewrite app/code/core/Mage/Cms/controllers/indexcontroller.php
more or less
public function defaultNoRouteAction()
{
$this->getResponse()->setHeader('HTTP/1.1','404 Not Found');
$this->getResponse()->setHeader('Status','404 File not found');
$this->loadLayout();
$this->renderLayout();
}
but i don't know how.

Answer 1

I've done something similar, exporting product data when calling an product-url with .xml instead of .html.
I've added an observer listening on product save event, that adds the product-xml URL into core_url_rewrite.
In that event, you have replace .htm(l) with .xml
e.g.
product-name.htm -> catalog/product/view/id/4 -> load product with ID 4 and render product view template, magento core
product-name.xml -> mycustommodule/product/view/id/4 -> load product with ID 4 and render XML, custom module
So you have to add another module called "mycustommodule" that handles the xml output.
Cheers!

Answer 2

i solution that i found is following,it work perfectly but didn't know for sure is it the MAGNETO-WAY
i rewrite Mage_Cms_IndexController noRoute Method,
public function noRouteAction($coreRoute = null) {
// getting current url
$url = Mage::helper('core/url')->getCurrentUrl();
if ( strstr($url,".jsonp") || strstr($url,".json") || strstr($url,".xml") ) {
// geting file-type like json / xml
$format = substr(strrchr($url, "."),1);
// product-handle
$elem = substr( strrchr($url, "/"),1, strpos( strrchr($url, "/") , ".")-1 );
switch ($format) {
case 'json': case 'JSON': case 'jsonp': case 'JSONP':
$this->getResponse()->setHeader('Content-type', 'application/json'); break;
case 'xml': case 'XML':
$this->getResponse()->setHeader('Content-type', 'application/xml'); break;
}
// loding product byproduct-handle
$rewrite = Mage::getModel('core/url_rewrite')->setStoreId(Mage::app()->getStore()->getId())->loadByRequestPath($elem . ".html");
$pid = $rewrite->getProductId();
$cat = Mage::getModel('catalog/category')->setStoreId(Mage::app()->getStore()->getId())->loadByAttribute('url_key', $elem );
if (strpos($url,"hs_review")) { echo Mage::getModel("Hs_Json/review")->wrapper($pid,$format);return;}
if ( $pid ) { echo Mage::getModel("Hs_Json/product")->wrapper($pid,$format);return; }
if ( $cat ) { echo Mage::getModel("Hs_Json/category")->wrapper($cat->getId(),$format);return;}
} else {
$this->getResponse()->setHeader('HTTP/1.1','404 Not Found');
$this->getResponse()->setHeader('Status','404 File not found');
$pageId = Mage::getStoreConfig(Mage_Cms_Helper_Page::XML_PATH_NO_ROUTE_PAGE);
if (!Mage::helper('cms/page')->renderPage($this, $pageId)) {
$this->_forward('defaultNoRoute');
}
}
}
}