Create Your First Magento Module

Magento module

Modules are the core functioning unit in a Magento system. Here I am giving an overview of how to write a “Hello World” module in magento. Simple basics before start you cooking :-)
At the time of instantiating, magento system reads all the Xmls inside the folder /app/etc/modules/ to get the list of active modules and their corresponding code repository . So very first step of creating a magento module is to declare the module and its core repository(the repository of the module, in magento it’s calles codepool ).
If you open /app/code/ you will see 3 coodpool :- core, community and local.
app/
|–code/
| |—community/
| |—core/
| |—local/
|
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The “core” cood pool is dedicated for magento’s all system modules. The “community” codepool is for all modules developed by magento’s partners and local is the codepool dedicated for you as a developer to write your own customized code.
In Magentos’ all modules are organized under a package. This package is nothing but a simple folder under codepool containing different modules. For example all core modules of magento system is kept unde package “Mage” (open the folder /app/code/code/ , you see the folder “Mage” under which all system module resides).

Namespace: Company
Modulename : Web

Step 1: Declare your shell module and it’s code pool
Create an xml file /app/etc/modules/Company_Web.xml (You can use any name, even you can use a single file to declare number of modules).

<?xml version="1.0"?>
<config>
    <modules>
        <Company_Web>
            <active>true</active>
            <codePool>local</codePool>
        </Company_Web>
    </modules>
</config> 

Step 2:
Create the basic directory structure under /app/code/local/ :-
Company/
|–Web/
| |–Block/
| |–controllers/
| |–etc/
| |–Helper/
| |–sql/
|

Step 3:
Write the front controller in app\code\local\Company\Web\controllers\IndexController.php

<?php
class Company_Web_IndexController extends Mage_Core_Controller_Front_Action
{
    public function indexAction()
    {
  $this->loadLayout();     
  $this->renderLayout();
    }
}

Step 4: Finally create the template file of your module app\design\frontend\default\default\template\web\web.phtml

<?php
 echo "Welcome to your custom module....";
?>

Step 5: Add the layout.xml as app\design\frontend\default\default\layout\web.xml

<?xml version="1.0"?>
<layout version="0.1.0">
    <default>
    </default>
    <web_index_index>
        <reference name="content">
            <block type="web/web" name="web" template="web/web.phtml" />
        </reference>
    </web_index_index>
</layout> 

Step 6: Now write the helper class app\code\local\Company\Web\Helper\Data.php

<?php

class Company_Web_Helper_Data extends Mage_Core_Helper_Abstract
{

}

Step 7:

Create the config file as app\code\local\Company\Web\etc\config.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Company_Web>
            <version>0.1.0</version>
        </Company_Web>
    </modules>
    <frontend>
        <routers>
            <web>
                <use>standard</use>
                <args>
                    <module>Company_Web</module>
                    <frontName>web</frontName>
                </args>
            </web>
        </routers>
        <layout>
            <updates>
                <web>
                    <file>web.xml</file>
                </web>
            </updates>
        </layout>
    </frontend>
    <global>
        <models>
            <web>
                <class>Company_Web_Model</class>
                <resourceModel>web_mysql4</resourceModel>
            </web>
            <web_mysql4>
                <class>Company_Web_Model_Mysql4</class>
                <entities>
                    <web>
                        <table>web</table>
                    </web>
                </entities>
            </web_mysql4>
        </models>
        <resources>
            <web_setup>
                <setup>
                    <module>Company_Web</module>
                </setup>
                <connection>
                    <use>core_setup</use>
                </connection>
            </web_setup>
            <web_write>
                <connection>
                    <use>core_write</use>
                </connection>
            </web_write>
            <web_read>
                <connection>
                    <use>core_read</use>
                </connection>
            </web_read>
        </resources>
        <blocks>
            <web>
                <class>Company_Web_Block</class>
            </web>
        </blocks>
        <helpers>
            <web>
                <class>Company_Web_Helper</class>
            </web>
        </helpers>
    </global>
</config>