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