Can my controller return the result of another controller action, without issuing a 301 or 302 redirect?

Question

I have a controller which replaces an existing controller. Under certain conditions my controller should run the implementation from the existing controller; however it should be transparent (it should behave like a URL rewrite with a non-redirect behavior).

So far I haven't been able to find out how I can either pass the request on to the second controller, or execute the second controller's action and return the result as though it were from my controller.

Answer 1

Take a look at the _forward method

abstract class Mage_Core_Controller_Varien_Action
 ...
 /**
 * Throw control to different action (control and module if was specified).
 *
 * @param string $action
 * @param string|null $controller
 * @param string|null $module
 * @param array|null $params
 */
 protected function _forward($action, $controller = null, $module = null, array $params = null)
{
 ....

E.g see newAction() in /app/code/core/Mage/Adminhtml/controllers/Cms/PageController.php

/**
 * Create new CMS page
 */
public function newAction()
{
 // the same form is used to create and edit
 $this->_forward('edit');
}
/**
 * Edit CMS page
 */
public function editAction()
{
 ...

Answer 2

Yes, just use \Mage_Core_Controller_Varien_Action::_forward