Need to convert to magento MVC structure - magento

Question

I have developed a code that contains a aquery which returns ratings of a product in json format. The code is as follows:
<?php header('content-type: application/json; charset=utf-8');
require_once('/opt/phpapps/magento/app/Mage.php');
umask(0);
Mage::app();
$cid=$_GET['catid'];
$read = Mage::getSingleton('core/resource')->getConnection('core_read');
$query = "SELECT round(t1.rating_summary / 20) AS rating, t2.product_id FROM review_entity_summary AS t1 INNER JOIN catalog_category_product AS t2 ON t1.entity_pk_value = t2.product_id WHERE category_id =" . $cid . " AND store_id = '1'";
$results = $read->fetchAll($query);
$json = json_encode($results);
print_r( $json );
?>
I am instructed to convert this into MVC pattern. I knew that MVC can be done by creating separate folders like blocks, controllers, models,sql,etc, helpers folders. But I am not sure what is the next stepa nd how to execute the developed to get the json data..
Help me in this...

Answer 1

The best way to is create a custom Extension/Model, there's a lot of tutorials out there to do this, however you could use something to generate an example for you to get started:
http://www.silksoftware.com/magento-module-creator/
However, for something this simple you could just create a custom block in the local namespace, for example:
app/code/local/Mage/Catalog/Block/Product/Ratingsjson.php
<?php
/**
* Ratingsjson.php
*/
class Mage_Catalog_Block_Product_Ratingsjson extends Mage_Catalog_Block_Product_Abstract
{
/**
* Get products with special offer attribute set
*
* #return type
*/
public function getRatings()
{
/**
* This will be injected from the tag / XML below
* you can pass what ever variables you want this way.
* getSomeAttribute() will get the value 'some_attribute' from the
* CMS tag or XML config.
*/
$categoryId = $this->getCategoryId();
if($categoryId == NULL) {
$categoryId = 1; // or some default;
}
$resource = Mage::getSingleton('core/resource');
$read = $resource->getConnection('catalog_read');
// Do your stuff here...
$query = "SELECT round(t1.rating_summary / 20) AS rating, t2.product_id FROM review_entity_summary AS t1 INNER JOIN catalog_category_product AS t2 ON t1.entity_pk_value = t2.product_id WHERE category_id =" . $cid . " AND store_id = '1'";
$results = $read->fetchAll($query);
return json_encode($results);
}
}
Create a template to do what you want:
template/mymodeule/mytemplate.phtml
<?php
echo $this->getRatings();
You can then use your new block inside CMS pages:
{{block type="catalog/ratignsjson" category_id="3" temaplte="mymodeule/mytemplate.phtml"}}
Or if you want to load it via XML config:
<block type="catalog/ratignsjson" category_id="3" name="ratignsjson" template="mymodeule/mytemplate.phtml"/>
To do this properly and output strict Json data you would want to set json content type headers etc but I think that's a little too much for this particular case.