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J2.5

Developing a MVC Component/Adding an install-uninstall-update script file

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< J2.5:Developing a MVC Component
Revision as of 07:22, 18 September 2012 by JoomlaWikiBot (Talk | contribs)

This tutorial is for Joomla 1.6 Joomla 1.7 Joomla 2.5


Introduction

This tutorial is part of the Developing a Model-View-Controller (MVC) Component for Joomla!2.5 tutorial. You are encouraged to read the previous parts of the tutorial before reading this.

Creating the extension script file

Installing, updating and uninstalling a component may require additional operations that cannot be achieved by the basic operations described in the main xml file. Joomla offers a new approach to solve this problem. It consists in using a php script file containing a class using five methods:

  • preflight which is executed before install and update
  • install
  • update
  • uninstall
  • postflight which is executed after install and update

Writing an extension script consists in declaring an class whose name is com_ComponentNameInstallerScript with these 5 methods.

script.php

<?php
// No direct access to this file
defined('_JEXEC') or die('Restricted access');
 
/**
 * Script file of HelloWorld component
 */
class com_helloWorldInstallerScript
{
	/**
	 * method to install the component
	 *
	 * @return void
	 */
	function install($parent) 
	{
		// $parent is the class calling this method
		$parent->getParent()->setRedirectURL('index.php?option=com_helloworld');
	}
 
	/**
	 * method to uninstall the component
	 *
	 * @return void
	 */
	function uninstall($parent) 
	{
		// $parent is the class calling this method
		echo '<p>' . JText::_('COM_HELLOWORLD_UNINSTALL_TEXT') . '</p>';
	}
 
	/**
	 * method to update the component
	 *
	 * @return void
	 */
	function update($parent) 
	{
		// $parent is the class calling this method
		echo '<p>' . JText::sprintf('COM_HELLOWORLD_UPDATE_TEXT', $parent->get('manifest')->version) . '</p>';
	}
 
	/**
	 * method to run before an install/update/uninstall method
	 *
	 * @return void
	 */
	function preflight($type, $parent) 
	{
		// $parent is the class calling this method
		// $type is the type of change (install, update or discover_install)
		echo '<p>' . JText::_('COM_HELLOWORLD_PREFLIGHT_' . $type . '_TEXT') . '</p>';
	}
 
	/**
	 * method to run after an install/update/uninstall method
	 *
	 * @return void
	 */
	function postflight($type, $parent) 
	{
		// $parent is the class calling this method
		// $type is the type of change (install, update or discover_install)
		echo '<p>' . JText::_('COM_HELLOWORLD_POSTFLIGHT_' . $type . '_TEXT') . '</p>';
	}
}

This script file will redirect the user to the com_helloworld component when it is installed and will display messages when it is updated or uninstalled. In the update method we show the new version using $parent->get('manifest')->version.

Adding some language keys

admin/language/en-GB/en-GB.com_helloworld.sys.ini""

COM_HELLOWORLD="Hello World!"
COM_HELLOWORLD_DESCRIPTION="This is the Hello World description"
COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_DESC="This view displays a selected message"
COM_HELLOWORLD_HELLOWORLD_VIEW_DEFAULT_TITLE="Hello World"
COM_HELLOWORLD_INSTALL_TEXT="HelloWorld Install script"
COM_HELLOWORLD_MENU="Hello World!"
COM_HELLOWORLD_POSTFLIGHT_DISCOVER_INSTALL_TEXT="HelloWorld postlight discover install script"
COM_HELLOWORLD_POSTFLIGHT_INSTALL_TEXT="HelloWorld postflight install script"
COM_HELLOWORLD_POSTFLIGHT_UNINSTALL_TEXT="HelloWorld postflight uninstall script"
COM_HELLOWORLD_POSTFLIGHT_UPDATE_TEXT="HelloWorld postflight update script"
COM_HELLOWORLD_PREFLIGHT_DISCOVER_INSTALL_TEXT="HelloWorld preflight discover install script"
COM_HELLOWORLD_PREFLIGHT_INSTALL_TEXT="HelloWorld preflight install script"
COM_HELLOWORLD_PREFLIGHT_UNINSTALL_TEXT="HelloWorld preflight uninstall script"
COM_HELLOWORLD_PREFLIGHT_UPDATE_TEXT="HelloWorld preflight update script"
COM_HELLOWORLD_UNINSTALL_TEXT="HelloWorld Uninstall script"
COM_HELLOWORLD_UPDATE_TEXT="HelloWorld Update script. HelloWorld now updated to version %s."

Packaging the component

Content of your code directory

Create a compressed file of this directory or directly download the archive and install it using the extension manager of Joomla. You can add a menu item of this component using the menu manager in the backend.

helloworld.xml

<?xml version="1.0" encoding="utf-8"?>
<extension type="component" version="2.5.0" method="upgrade">
 
	<name>COM_HELLOWORLD</name>
	<!-- The following elements are optional and free of formatting constraints -->
	<creationDate>November 2009</creationDate>
	<author>John Doe</author>
	<authorEmail>john.doe@example.org</authorEmail>
	<authorUrl>http://www.example.org</authorUrl>
	<copyright>Copyright Info</copyright>
	<license>License Info</license>
	<!--  The version string is recorded in the components table -->
	<version>0.0.15</version>
	<!-- The description is optional and defaults to the name -->
	<description>COM_HELLOWORLD_DESCRIPTION</description>
 
	<!-- Runs on install/uninstall/update; New in 2.5 -->
	<scriptfile>script.php</scriptfile>
 
	<install> <!-- Runs on install -->
		<sql>
			<file driver="mysql" charset="utf8">sql/install.mysql.utf8.sql</file>
		</sql>
	</install>
	<uninstall> <!-- Runs on uninstall -->
		<sql>
			<file driver="mysql" charset="utf8">sql/uninstall.mysql.utf8.sql</file>
		</sql>
	</uninstall>
	<update> <!-- Runs on update; New in 2.5 -->
		<schemas>
			<schemapath type="mysql">sql/updates/mysql</schemapath>
		</schemas>
	</update>
 
	<!-- Site Main File Copy Section -->
	<!-- Note the folder attribute: This attribute describes the folder
		to copy FROM in the package to install therefore files copied
		in this section are copied from /site/ in the package -->
	<files folder="site">
		<filename>index.html</filename>
		<filename>helloworld.php</filename>
		<filename>controller.php</filename>
		<folder>views</folder>
		<folder>models</folder>
		<folder>language</folder>
	</files>
 
	<media destination="com_helloworld" folder="media">
		<filename>index.html</filename>
		<folder>images</folder>
	</media>
 
	<administration>
		<!-- Administration Menu Section -->
		<menu img="../media/com_helloworld/images/tux-16x16.png">COM_HELLOWORLD_MENU</menu>
		<!-- Administration Main File Copy Section -->
		<!-- Note the folder attribute: This attribute describes the folder
			to copy FROM in the package to install therefore files copied
			in this section are copied from /admin/ in the package -->
		<files folder="admin">
			<!-- Admin Main File Copy Section -->
			<filename>index.html</filename>
			<filename>config.xml</filename>
			<filename>access.xml</filename>
			<filename>helloworld.php</filename>
			<filename>controller.php</filename>
			<!-- SQL files section -->
			<folder>sql</folder>
			<!-- tables files section -->
			<folder>tables</folder>
			<!-- models files section -->
			<folder>models</folder>
			<!-- views files section -->
			<folder>views</folder>
			<!-- controllers files section -->
			<folder>controllers</folder>
			<!-- helpers files section -->
			<folder>helpers</folder>
		</files>
 
		<languages folder="admin">
			<language tag="en-GB">language/en-GB/en-GB.com_helloworld.ini</language>
			<language tag="en-GB">language/en-GB/en-GB.com_helloworld.sys.ini</language>
		</languages>
	</administration>
 
</extension>

Zips

Download the zip file for this Part: [1]

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