Simple module Development in Joomla! 2.5

Vishwash Gaur

© 2012 Vishwash Gaur. All rights reserved.
All registered trademarks, logos, products and service names belong to their
respective owners.
Image Credit: http://ayadipro.com/blog/high-tech-education/25-improvements-in-joomla-2-5/
Disclaimer: Images used on this slide are for representative purposes only and belong to their respective owners.

 Basic knowledge of HTML, PHP and MySQL
 Interest in MVC and CMS frameworks to reduce development
time
 A web server with PHP/MySQL installed on it
 Joomla! 2.5 package downloaded and installed
◦ it can be downloaded from http://www.joomla.org/download.html

 NOTE: This presentation is focused for the beginners in Joomla! and would
cover only a basic overview due to limited time. Further details can be
discussed separately later.

Hands on workshop to
develop a basic Joomla!
Module and component

 Let’s create a module called “Reviews” for this
workshop which will display customer reviews
on the web page
 It will allow us to display a simple text in a
pre-defined Joomla module position
 Once this is done, we will fetch data for the
module from DB

 modules>mod_reviews
◦ mod_reviews.php
◦ mod_reviews.xml
◦ helper.php
◦ index.html
◦ tmpl/default.php
◦ tmpl/index.html

<?php
//license details here

// no direct access
defined( '_JEXEC' ) or die( 'Restricted access' );

// Include the syndicate functions only once
require_once( dirname(__FILE__).DS.'helper.php' );

//load helper class and function
$reviews = modReviewsHelper::getReviews( $params );

//load the layout file from template views
require( JModuleHelper::getLayoutPath( 'mod_reviews' ) );
?>

// no direct access

As it suggests, this line checks to make sure that this
file is being included from the Joomla! application.
It is necessary to prevent variable injection and other
potential security concerns.

The helper class is defined in our helper.php file.
This file is included with a require_once statement.
It allows to include necessary functions for the
module functionality. Helper file may include basic
calculations, DB connection and query code.

$reviews = modReviewsHelper::getReviews( $params );

This line allows to invoke the appropriate helper class method
to retrieve the data.
Currently, we do not use any parameters but it is allowed in this
module for future extensibility.


This line includes the template to display the output.

<?xml version="1.0" encoding="utf-8"?>
<extension
type="module"
version="2.5"
client="site"
method="upgrade">
<name>Reviews</name>
<author>Vishwash Gaur</author>
<version>2.5.0</version>
<description>An review module.</description>
<files>
<filename module="mod_reviews">mod_reviews.php</filename>
<filename>index.html</filename>
<filename>helper.php</filename>
<folder>tmpl</folder>
<filename>mod_reviews.xml</filename>
</files>
</extension>

This file is used to specify which files the installer needs to copy
and is used by the Module Manager to determine which
parameters are used to configure the module.

<extension type="module“ version="2.5“
client="site“ method="upgrade">

This line tells to Joomla! that selected
extension type is module and compatible with
Joomla version 2.5.
Extension type is also defined for site which
means it will be available for front-end.

<files>
<filename
module="mod_reviews">mod_reviews.php</filename>
</files>

<install type="module" version="1.5.0">
<name>Hello, World!</name>
<author>John Doe</author>
<description>A simple Hello, World! module.</description>
<files>
<filename>tmpl/default.php</filename>
<filename>tmpl/index.html</filename>
</files>
<params>
</params>
</install>

<?php

class modReviewsHelper
{
/**
* Retrieves the reviews
*
* @param array $params An object containing the module parameters
* @access public
*/
function getReviews( $params )
{
return 'I am a happy user!';
}
}
?>

<html><body bgcolor="#FFFFFF"></body></html>

This file is included to prevent directory browsing. It can be
event left blank and whenever someone will access the
directory then this file will be default loaded.

<?php
// no direct access
//print user reviews
echo $reviews;
?>

 Once a base module is ready, we can start using it
immediately in Joomla.
 In Joomla 1.5, it was auto-detected but in Joomla
2.5, we would need to discover a newly developed
extension from admin panel.
 For this, please login to admin panel and go to Top
menu>extensions>extension manager
 Click on the discover tab and refresh the data

Simple module Development in Joomla! 2.5

Click on the
discover button
to find newly
developed
extensions

If your programming is
correct, it will find your newly
developed extension.
Select the extension and click
on install button to setup the
extension.

 Once a module is added in the Joomla! System, it
has to be defined on a position using module
manager.
 It will allow module to display in the front-end.

Go to module manager
and click on “New”
button

Select your newly
developed module

Define module
position in active
template and set
other parameters and
pages to display the
module.
I give it position 6 in
Beez_20 template.

Module successfully
saved, now move to
front-end to check this.

 I can’t see the module
◦ Check if you have selected correct position in the
active template

 With the previous example, you can display one
static customer review but what if there are many
customer reviews which should be dynamically
loaded on the page.
 Let’s do that!

 Using phpMyAdmin or any other DB management
tool, create a table called __reviews in the Joomla
DB
 Add required fields i.e. id, name, city and feedback
in the table
 Kindly note this example is meant to be very basic
for easy understanding

Create table and add
fields in the database.
Note: Ideally, it is the
part of component.

I have done some entries in the DB directly
for the demo purpose. It should happen
via a back-end component in real
environment.

 Now, since we are not doing any static code
and want to load reviews dynamically from
the database, we need to make some changes
in below files:
◦ mod_reviews.php – minor change
◦ helper.php – major change for DB connection and
query
◦ tmpl/default.php – minor change
◦ tmpl/reviews.php – new template file added

<?php

// no direct access


//$reviews = modReviewsHelper::getReviews( $params );
$rows = modReviewsHelper::getReviews( $params );

?>

<?php

class modReviewsHelper
{
/**
* Retrieves the reviews
* @access public
For the demonstration
*/
function getReviews( $params )
purpose, kindly understand
{
//return 'I am a happy user!';
and note that Joomla! uses
//limit the number of items to load from DB
$items = $params->get('items', 10);
it’s own code conventions
//make DB connection
to make DB connections and
$db=& JFactory::getDBO();
$result= null;
to run a query. It allows in
//run db query
$query = 'SELECT * FROM #__reviews';
less code and standardized
$db->setQuery($query, 0, $items);
$rows = $db->loadObjectList();
approach.
//display and handle error warning
if ($db->getErrorNum()) {
JError::raiseWarning( 500, $db->stderr(true) );
}
return $rows;
}

/**
* Function to display rating and reviews via views
* @access public
*/
function renderReviews(&$reviews, &$params)
{
//variable to store db value of a particular record link to open in detailed view
$link = JRoute::_('index.php?option=com_reviews&id='.$reviews->id.'&task=view');

//call template view for display
require(JModuleHelper::getLayoutPath('mod_reviews' , 'reviews'));
}
}
?>

This component doesn’t exists in the system but we have planned
it for future use or next demo of component development.

<?php
// no direct access
//print user reviews
//echo $reviews;
foreach($rows as $row)
{
modReviewsHelper::renderReviews($row, $params);
}
?>

<?php
// no direct access
defined( '_JEXEC' ) or die( 'Restricted access' ); ?>
<table width="95%">
<tr><td>
<strong><?php echo ucwords(strtolower($reviews->name)); ?></strong>
<br />
<span style="font-size:9px; margin-top:-5px;">
<?php echo ucwords(strtolower($reviews->city));?></span><br />
</td>
</tr>
<tr>
<td><?php echo wordwrap($reviews->feedback,130, "<br />n");?></td>
</tr>
</table>

 Get your XAMP, LAMP, MAMP or WAMP environment
ready
 Install and experiment Joomla! Locally
 Checkout online references
 Get a book
 Visit Joomla! JED, Forums and user groups
 Help each other and learn from experiences

 I look forward to learn and share more with you in
future too.

 I can be reached easily at my blog
www.vishwashgaur.com and/or using twitter
@vishwashgaur

 XAMP: http://www.apachefriends.org/en/xampp.html
 Joomla!: http://www.joomla.org/
 JED: http://extensions.joomla.org/
 Joomla! Forum: http://forum.joomla.org/
 Joomla! Magazine: http://magazine.joomla.org/authors/itemlist/user/65-Nicholas-G-Antimisiaris
 Joomla documentation: http://docs.joomla.org/
 Joomla 2.5 essential training: http://www.lynda.com/Joomla-tutorials/Joomla-Essential-Training/95699-2.html
 Joomla! For beginners guide 2012: http://www.danconia.com/joomla-for-beginners-guide-2012.html
 Joomla! Developers guide: http://cocoate.com/sites/cocoate.com/files/private/jdev.pdf

Simple module Development in Joomla! 2.5

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