Override/Rewrite Magento core blocks and controllers
After spending many hours in rewriting block and controller of Magento core module, I finally came up with a solution.
Here I am going to rewrite block: Mage/Adminhtml/Block/Sales/Shipment/Grid.php
and controller: Mage/Adminhtml/controllers/Sales/ShipmentController.php
First you will need to make a xml file for your new module at app/etc/modules directory
CompanyName_Adminhtml.xml
<?xml version="1.0"??>
<config>
<modules>
<companyname_adminhtml>
<active>true</active>
<codepool>local</codepool>
</companyname_adminhtml>
</modules>
</config>
Then, make folders in your app/code/local directory as follows:
– CompanyName
-> Block
—> Sales
—-> Shipment
——> Grid.php
-> controllers
—> Sales
—-> ShipmentController.php
-> etc
—> config.xml
In etc/config.xml, your code should look like below:
<?xml version="1.0"??>
<config>
<modules>
<companyname_adminhtml>
<version>0.1.0</version>
</companyname_adminhtml>
</modules></config>
<global>
<blocks>
<adminhtml>
<rewrite>
<sales_shipment_grid>CompanyName_Adminhtml_Block_Sales_Shipment_Grid</sales_shipment_grid>
</rewrite>
</adminhtml>
</blocks></global>
<routers>
<adminhtml>
<rewrite>
<sales_shipment>
<from><![CDATA[#^/admin/sales_shipment/$#]]></from>
<to>/admin/sales_shipment/</to>
</sales_shipment>
</rewrite>
</adminhtml>
</routers>
<admin>
<routers>
<adminhtml>
<args>
<modules>
<companyname_adminhtml before="Mage_Adminhtml">CompanyName_Adminhtml</companyname_adminhtml>
</modules>
</args>
</adminhtml>
</routers>
</admin>
In ShipmentController.php, you should start like this:
require_once(“Mage/Adminhtml/controllers/Sales/ShipmentController.php”);
class CompanyName_Adminhtml_Sales_ShipmentController extends Mage_Adminhtml_Sales_ShipmentController
{
//controller methods goes here..
}require_once is necessary as magento is not going to load controllers as it does for blocks and models
In block Grid.php, start the file like below:
class CompanyName_Adminhtml_Block_Sales_Shipment_Grid extends Mage_Adminhtml_Block_Widget_Grid
{
// block methods goes here..
}That’s it! Now you should get your local Grid.php and ShipmentController.php loading instead of core’s.