This document discusses how to write custom modules for three different PHP-based e-commerce systems: Magento, OXID eShop, and Shopware. It provides an overview of each system's architecture and module structure. For Magento, it describes how to drill down from templates to models and databases to access product information. For OXID, it explains how to extend classes and integrate custom functionality using an event-listener system. For Shopware, it outlines how to use plugins, events, hooks, and listeners to insert custom code. The document concludes that while each system has slightly different methods, custom modules can be added without core hacking by leveraging each system's extensibility features and testing custom code

1. How to write Custom
Modules for PHP-based E-
Commerce Systems
Dr. Roman Zenner

2. Roman Zenner
• Working as freelance trainer, author and
developer since 2004
• Has written two books on Magento
• Is in the process of writing a book on
OXID eShop
• Publishes in various magazines

3. Initial thoughts
• Modularity a no-brainer in today’s
ecommerce software
• There must be a way of extending
classes or an event-listener system in
order to integrate custom functionalities

4. Types of modules
• Encapsulate graphical (template)
changes
• Provide additional information (e.g. for
an article
• Special calculations
• Payment and shipping
• Other interfaces (ImpEx, etc.

5. Today‘s candidates
• Magento
• OXID eShop
• Shopware

6. http://www.flickr.com/photos/exey/3815327201

7. MVC-Model (extended)

9. Brief History
• First stable version released in spring 2008
• Community Edition under OSL
• Professional and Enterprise Editions
• Based on Zend Framework and MySQL
• Relies heavily on EAV structure
• XML definitions
• Bought by eBay in 2011 (X.commerce)
• Current stable version: 1.6.1

10. Structure

11. Templates (1)

12. Templates (2)

13. Templates (2)
<block type="page/html“ name="root" output="toHtml“ template="page/3columns.phtml">
<block type="page/html_header" name="header" as="header">
<block type="page/switch" name="store_language" as="store_language"
template="page/switch/languages.phtml"/></block>
</block>
Template: /layout/page.xml
<?php if(count($this->getStores())>1): ?>
<div class="form-language“>
<?php foreach ($this->getStores() as $_lang): ?>
<?php $_selected = ($_lang->getId() == $this->getCurrentStoreId())
? ' selected="selected"' : '' ?>
<option value="<?php echo $_lang->getCurrentUrl() ?>"<?php echo $_selected ?>>
<?php endforeach; ?>
</div>
<?php endif; ?>
Template: /template/page/switch/languages.phtml

14. Drilling down (1)
Example:
How to get from the article name in
the template to the database field?

15. Drilling down (2)
1. Block: <block type="catalog/product_view" name="product.info" template="catalog/
product/view.phtml">
2. Template: /app/design/frontend/base/default/template/catalog/product/view.phtml
3. Block class: Mage_Catalog_Block_Product_View
4. Model: Mage_Catalog_Model_Product:
public function getProduct()
{
if (!Mage::registry('product') && $this->getProductId()) {
$product = Mage::getModel('catalog/product')->load($this->getProductId());
Mage::register('product', $product);
}
return Mage::registry('product');
}

16. Drilling down (3)
1. Abstract class: Mage_Core_Model_Abstract
2. Resource model: Mage_Core_Model_Mysql4_Abstract
public function load($id, $field=null)
{
$this->_beforeLoad($id, $field);
$this->_getResource()->load($this, $id, $field);
$this->_afterLoad();
$this->setOrigData();
$this->_hasDataChanges = false;
return $this;
}

17. Modules (1)

18. Modules (2)
IDE, please!

20. Brief History
• OS-Edition since late 2008.
• Based on own PHP-Framework & MySQL
• Recent version: 4.5.3

21. Features
• ADODB database abstraction layer
• Uses Smarty 2 (but Template Inheritance by
Smarty 3)
• Block Inheritance
• Autoloader

22. Structure

23. Template Inheritance (1)

24. Template Inheritance (2)
[{capture append="oxidBlock_content"}]
[{assign var="oFirstArticle" value=$oView->getFirstArticle()}]
[{/capture}]
[{include file="layout/page.tpl" sidebar="Right"}]
/out/azure/tpl/page/shop/start.tpl

25. Template Inheritance (3)
<div id="content">
[{include file="message/errors.tpl"}]
[{foreach from=$oxidBlock_content item="_block"}]
[{$_block}]
[{/foreach}]
</div>
[{include file="layout/footer.tpl"}]
/out/azure/tpl/layout/page.tpl

26. Drilling down (1)
Example:
How to get from the article name in
the Smarty-Template to the database field?

27. Drilling down (1)
Example:
How to get from the article name in
the Smarty-Template to the database field?

28. Drilling down (2)
• Article detail page: /out/azure/tpl/page/details/inc/productmain.tpl
[{block name="details_productmain_title"}]
<h1 id="productTitle"><span itemprop="name">
[{$oDetailsProduct->oxarticles__oxtitle->value}]
[{$oDetailsProduct->oxarticles__oxvarselect->value}]</span></h1>
[{/block}]
Scheme: [Object name]->[Table name]__[Field name]->value
• View controller: /views/details.php

29. Drilling down (3)
public function render()
{
$myConfig = $this->getConfig();
$oProduct = $this->getProduct();
}
public function getProduct()
{
$sOxid = oxConfig::getParameter( 'anid' );
$this->_oProduct = oxNew( 'oxarticle' );
if ( !$this->_oProduct->load( $sOxid ) ) {
...
}
}

30. Drilling down (4)
public function load( $oxID)
{
$blRet = parent::load( $oxID);
public function load( $sOXID)
{
//getting at least one field before lazy loading the object
$this->_addField('oxid', 0);
$sSelect = $this->buildSelectString( array( $this->getViewName().".oxid" => $sOXID));
return $this->_isLoaded = $this->assignRecord( $sSelect );
}
/core/oxarticle.php
/core/oxbase.php

31. Custom classes (1)
• Most view- and core classes can be overloaded
• Module are registered in backend
• Object instantiation via oxNew(): core/oxutilsobject.php
oxArticle
my_oxArticle
our_oxArticle
class my_oxArticle extends oxArticle
class our_oxArticle extends my_oxArticle

32. Custom classes (2)
• This procedure becomes problematic when there is more
than one new module wanting to extend a specific class.
• Solution: oxNew() dynamically creates transparent
classes in the form of: [class-name]_parent
• This means that by means of the following structure,
module classes can be chained:
– oxArticle => my_oxArticle&our_oxArticle

33. Plugins (1)
• Task: Write a module that displays the remaining time until
X mas with each article.
1. New module directory: /modules/xmas/
2. Publishing it via Admin:

34. Plugins (2)
class xmasArticle extends xmasArticle_parent
{
public function getDaysLeft()
{
$time = mktime(0, 0, 0, 12, 25, 2011, 1) - time();
$days = floor($time/86400);
return $days;
}
}
<div>Only [{$oDetailsProduct->getDaysLeft()}] days left until Xmas!</div>
/modules/xmas/xmasArticle.php
/out/azure/tpl/page/details/inc/productmain.tpl

36. Brief History
• First stable version released in 2007.
• OS-Edition since October 2010.
• Since v.3.5 based on Enlight Framework
(based on ZF) & MySQL
• MVC-Model
• Backend based on ExtJS 4
• Templates based on Smarty 3
• Recent version: 3.5.5

37. Enlight-Framework
• Basis functionalities are inherited from Zend
Framework:
• Syntax and Workflow
• Request- and Response-Objects
• Action-Controller Design
• Rewritten Router / Dispatcher and View-
Object optimised for performance and
expandability
• Own plugin system based on events and
hooks

38. Template-Structure

39. index.tpl
{* Content section *}
<div id="content">
<div class="inner”>
{* Content top container *}
{block name="frontend_index_content_top"}{/block}
{* Sidebar left *}
{block name='frontend_index_content_left'}
{include file='frontend/index/left.tpl'}
{/block}
{* Main content *}
{block name='frontend_index_content'}{/block}
{* Sidebar right *}
{block name='frontend_index_content_right'}{/block}
<div class="clear">&nbsp;</div>
</div>
</div>

40. Template-Inheritance
{extends file=”../_default/frontend/home/index.tpl}
{block name=’frontend_index_content’ prepend}
<h1>Hallo Welt</h1>
{/block}
SMARTY:
Append – Prepend - Replace

41. Plugin-Directory Structure

42. Drilling down
Example:
How to get from the article name in
the Smarty-Template to the database field?

43. Drilling down (2)
• Article detail page: templates_defaultfrontenddetailindex.tpl
• Part that displays article name in frontend
• Template-Path (frontend/detail/index.tpl) tells us where to find the
corresponding controller. In this case: Shopware/Controllers/
Frontend/Detail.php – indexAction.
• Get article information from Model and assign to template
• Shopware()->Modules()->Articles() is a service locator to access the
main article object that could be found at /engine/core/class/
sArticles.php
• sGetArticleById fetches a certain article by id from database and
returns the result as an array for further processing

44. Plugins: Bootstrap
<?php
class Shopware_Plugins_Frontend_IPCDEMO_Bootstrap
extends Shopware_Components_Plugin_Bootstrap
{
public function install()
{
//
return true;
}
public static function onPostDispatch(Enlight_Event_EventArgs $args)
{
// Still empty
}
}

45. Plugins: Event
public function install()
{
$event = $this->createEvent('Enlight_Controller_Action_PostDispatch','onPostDispatch');
$this-> subscribeEvent($event);
$form = $this->Form();
$form->setElement('textarea', ’yourtext',
array('label'=>’Text for left column’,'value'=>’Hello World'));
$form->save();
return true;
}

46. Plugins: Listener
!public static function onPostDispatch(Enlight_Event_EventArgs $args)
{
$view = $args->getSubject()->View();
$config = Shopware()->Plugins()->Frontend()->IPCDEMO()->Config();
$view->pluginText = $config->yourtext;
$view->addTemplateDir(dirname(__FILE__)."/Views/");
$view->extendsTemplate('plugin.tpl');
}

47. Plugins: Hooks
<?php
class Shopware_Plugins_Frontend_myHook_Bootstrap extends Shopware_Components_Plugin_Bootstrap
{
public function install()
{
$hook = $this->createHook(
'sArticles',
'sGetArticleById',
'onArticle',
Enlight_Hook_HookHandler::TypeAfter,
0
);
$this->subscribeHook($hook);
return true;
}
static function onArticle(Enlight_Hook_HookArgs $args)
{
}
}

48. Summary
• Each system employs a slightly different method of
inserting custom functionalities
• Layout and functional files are more or less
encapsulated
• No core-hacking required – still a need for testing!

49. ?

50. Thank you!
Blog: romanzenner.com
Skype: roman_zenner
XING: xing.com/profile/Roman_Zenner
Twitter: twitter.com/rzenner