Question

I’m little bit new to Zend, I want to use a controller action through out the entire application automatically, I don’t have a clear idea to how to use it, thought about init() method, action helpers, etc.

Answer 1

Then instead of simply creating controller action create controllerAction Helper . Here you can find more about it

http://framework.zend.com/manual/en/zend.controller.actionhelpers.html

My_Helper_Magic extends Zend_Controller_Action_Helper_Abstract
{

public function preDispach()
{
     //code inside here will run for entire application automatically
}

}

In your bootstrap do

Zend_Controller_Action_HelperBroker::addHelper(new My_Helper_Magic());

In Response to comment .

It depends upon your ‘code fragment’ , If your code fragment does not required to know nothing about module , controller, action , base url then you can use Bootstrap init function

like

public function _initAlways()
{
//see how this function name is prefixed with _init hence it will be called by ZF //everytime. You can put your code fragment here 
//If your code fragment depends upon some stuff like baseurl then do action controller
// registration here instead 
 Zend_Controller_Action_HelperBroker::addHelper(new My_Helper_Magic());

}

In Response To comment

You can save any instance of your object inside Zend_Registy and retrieve it whereever you like

Inside Bootstrap.php

public function _initSetup()
{
$object = new My_Custom_Object();
Zend_Registry::set('my_custom_object',$object);
}

Later in your view or controller do

$myObject = Zend_Registry::get('my_custom_object');  //to access it