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