Creating components

In this category I will try to write about creating extensions in Joomla!

First, I will start with creating components.

This example, I took from Professional Joomla!, which I simplified, this is not MVC, as much as I think, but it is good as a starting point.

We will create three files: admin.hellopost.php, hellopost.php and hellopost.xml.

hellopost.xml we need for installation and it look like this:

<?xml version="1.0" encoding="utf-8"?>
<install version="1.5.0" type="component">
     <name>HelloPost</name>
     <author>Stanko Milosev</author>
     <version>1.0.0</version>
     <description>Hello world, posting from form</description>
     <files>
          <filename component="com_hellopost">hellopost.php</filename>         
     </files>
     <install>
     </install>

     <uninstall>
     </uninstall>
     <administration>
         <menu>Hello post</menu>
         <files>
              <filename component="admin.hellopost">admin.hellopost.php</filename>         
         </files>
     </administration>
</install>
 

Now hellopost.php:

 <?php
/**
* @version $Id: guestbook.php 5203 2007-06-15 02:45:14Z DanR $
* @copyright Copyright (C) 2007 Dan Rahmel. All rights reserved.
* @package Guestbook
* This component displays guestbook entries and allows the addition
* of entries from registered users.
*/

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

// Check the task parameter and execute appropriate function
switch( JRequest::getVar( 'task' )) { 
    case 'hello': 
        hello(); 
        break; 
    default: 
        displayHello(); 
        break; 
} 

// Process data received from form.
function hello()  {      
echo JRequest::getVar( 'hello' );
}

// Output a list of guestbook entries
function displayHello() {     
?>

<form action="index.php?option=com_hellopost&task=hello" method="post" id="formica" name="formica">
   Say:
      <input type="text" size="20" name="hello" value="Hello world"/>
      <input type="submit" value="Submit" name="Submit"/>
</form>
                

<?php     
} 
?>
 

With JRequest::getVar( 'task' ) we get variables which we posted ($_POST in pure PHP), my problem is that I coudn't do it with get method.

In case that JRequest::getVar( 'task' ) is equal hello (in PHP would be $_POST['task']=='hello'), than we call hello function in other case we call displayHello.

admin.hellopost.php I didn't change, but I think that file could be even empty. Component you can download from here.