The request object in CakePHP permits you to find out the current status of the incoming request while the response object permits you to easily make HTTP responses from your controllers.
By default cakephp uses Request as a request object. It incorporates various features for questioning and cooperating with request information. On every request one Request is made and afterward passed by reference to the different layers of an application that utilization demand information
In cakephp the default response class is cake/Network/Response .It have lots of features for creating and generating HTTP responses in our application, It is also used in testing, as it will allow us to inspect headers that was sent.
Changing Response class
If we want to change responce class we can do this in webroot/index.php. We can replace Response in there. This will make all our controllers to use CustomResponseand not to use Cake/Network/Response.