Magento 2 controller override

It is a quite simple tutorial with 2 steps:

Step 1:

Create di.xml file at app/code/[Name space]/[Your Module]/etc

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../lib/internal/Magento/Framework/ObjectManager/etc/config.xsd">
   <preference for="MagentoCmsControllerIndexIndex" type="[Name Space][Your Module]ControllerCmsIndex" />
</config>

In this example, we will rewrite controller Magento/Cms/Controller/Index/Index. In which, [Name Space][Your Module]ControllerCmsIndex will be used to override MagentoCmsControllerindexIndex –the homepage in original Magento 2.

Step 2: Define an overriding controller class

You need to create Index.php in app/code/[Name Space]/your Module]/Controller/Index

<?php

namespace [Name Space][Your Module]ControllerIndex;
class Index extends MagentoCmsControllerIndexIndex
{
public function execute($coreRoute = null)
{
    // todo

}
}

Done! I’m sure that you can follow this tutorial without any difficulty.