This book will guide you through the complexities of implementing components, modules, and plugins in Joomla! 1.5. It provides useful reference material that explains many of the advanced design features and classes available in Joomla! 1.5.
Joomla! is one of the world's top open source content management systems. The main sources of the PHP MySQL application's success are its comprehensive extension libraries, which extend Joomla! far beyond content management, and it's very active forums where one can easily tap into the knowledge of other Joomla! users, administrators, and developers.
One of the most pleasurable things about working with Joomla! is the encouragement of openness and friendliness among the members of the Joomla! community. It is, without a doubt, the community that is driving the Joomla! project. The name 'Joomla!' is derived from the Swahili word 'Jumla', meaning 'all together'. The Joomla! community lends a true sense of jumla to the project.
The architecture of the latest version of Joomla! differs in many ways from previous versions. Resultantly backward-compatibility with some extensions has been broken; the race is on for developers to update their skills in order to rectify the problems and start building new extensions. Perhaps the most important of the changes is the reorganization and classification of files and classes. This change encourages but does not force developers to use the Joomla! libraries consistently between extensions.
Rice Studios, formerly Miro, created a closed-source CMS called 'Mambo' in the year 2000. One year later, Mambo was re-licensed under two separate licenses, one of which was open source. The open-source version became known as 'Mambo Site Server'.
In 2002 Mambo Site Server was re-branded 'Mambo Open Source' (Also referred to as MamboOS or MOS) in an attempt to differentiate the commercial and open source flavors of Mambo. All rights to Mambo Open Source were officially released into the open source community in 2003.
Mambo Open Source was extremely successful and won a large number of prestigious open-source awards.
In 2005 the commercial version of Mambo was re-branded as 'Jango'. Rice Studios, at that time still Miro, also chose to form the Mambo Foundation, a non-profit organization. The intention was to create a body that would help protect the principles of Mambo and provide a more structured working methodology.
The creation of the Mambo Foundation created a rift in the Mambo Open Source community. The creation of the Mambo Foundation was seen by many as an attempt by Rice Studios to gain control of the Mambo Open Source project.
Not long after the Mambo Foundation was created, a group, consisting mainly of the Mambo Open Source core developers, publicly announced that they intended to abandon Mambo Open Source. The group formed a non-profit organization called 'Open Source Matters'.
Open Source Matters created the Joomla! project, a guaranteed 100% open-source GPL project. The first release of Joomla! (Joomla! 1.0) was very similar to the then current release of Mambo, the majority of extensions at the time being compatible with both.
Restraints within Joomla! 1.0 led to a complete re-think of how Joomla! should be constructed. After a long development period, and two beta releases, Joomla! 1.5 was released in mid 2007.
Joomla! 1.5 is extensively different to Joomla! 1.0 and Mambo. Joomla! 1.5 introduces many new classes and implements a comprehensive framework. These changes have lead to reduced compatibility between Joomla! and Mambo.
The most notable change, for most third-party extension developers, is the introduction of the MVC (Model View Controller) design pattern in components. These changes now mean that all third-party developers tend to develop for Joomla! or Mambo, but not both. The MVC design pattern is discussed in depth in Chapter 5 , Component Design.
Chapter 1 , Introduction to Joomla! introduces the technology in general, covering the software framework that is the foundation for Joomla! 1.5, along with an overview of how it can be extended. It briefly discusses development tools that are readily available for use in developing Joomla! extensions.
Chapter 2 , Getting Started covers the basics of object oriented design as it applies to Joomla! The complete application process, from request to response is covered, a few core classes are introduced, and the basic Joomla! directory structure discussed.
Chapter 3 The Database deals with the database. It talks about extending the database, conventions for the database schema, and common fields. Then the focus moves on to storing data, common types of data in standard fields and dealing with multilingual requirements. We then cover querying the database and getting results.
Next, the chapter explores how to manipulate common field types. The chapter concludes with a brief description of the JTable. The JTable is used to display and edit regular two-dimensional tables of cells. The JTable has many facilities that make it possible to customize its rendering and editing but provides defaults for these features so that simple tables can be set up easily.
Chapter 4
, Extension Design covers the basics in extension design. We begin with helper classes, then cover building and using getInstance() methods. We cover the registry along with saving and loading registry values. We explain the User, Session, Browser and Assets. We finish the chapter with a discussion on the structure of components, modules, and plugins and explain extension packaging and developing XML manifest files for each.
Chapter 5 , Component Design is about designing components. It starts with the structure and a basic design of a component using the MVC design pattern. Then we learn configuring the component and its various elements and parameters.
Chapter 6 , Module Design covers designing modules. It explains standalone modules, module settings, frontend and backend modules, and modules and components working together. Then we talk about using templates.
Chapter 7 , Plugin Design deals with designing plugins. It initially deals with listeners/observers and then the various plugin groups like authentication, content editors, search, and others. Then comes loading, translating, and using plugins as libraries. Finally it deals with, plugin settings.
Chapter 8
, Rendering Output explains ways to render output and how to maintain consistency throughout. It starts with the joomla.html library and then continues to describe how to build component HTML layouts. Then it discusses how to output the backend of a component. The chapter ends with the details of itemized data and pagination.
Chapter 9 , Customizing the Page deals with customizing the page. We cover things like modifying the document and translating, along with a brief explanation of using JavaScript effects from the Mootools library, which is included in Joomla!.
Chapter 10 , APIs and Web Services explores some of the Joomla! APIs, specifically in relation to web services. We also discuss some of the more common web services and take a more in-depth look at the Yahoo! Search API. The chapter finishes by describing how we can create our own web services using plugins.
Chapter 11 , Error Handling and Security provides an introduction to handling and throwing errors, warnings, and notices. Further, it talks about building secure Joomla! extensions. It also describes a number of common mistakes made when coding with Joomla! and explains how to avoid them.
Chapter 12 , Utilities and Useful Classes explains various utilities and useful classes like dates, arrays, tree structures, and others.
The Appendices detail many of the Joomla! classes. Appendix B-H are only available as a download at https://www.packtpub.com//sites/default/files/0523_Code.zip.
Appendix A , Joomla! Core Classes provides detailed information covering the Joomla! core classes.
Appendix B
, Parameters (Core Elements) provides information on how to handle the ever-useful JParameter class.
Appendix C
, Site Configuration Settings describes the Joomla! configuration settings and the JRegistry class.
Appendix D
, Menus and Toolbars details menus and toolbars discussing the JMenu and JPathway classes and providing complete information on toolbar buttons.
Appendix E
, Joomla! HTML Library provides complete coverage of the joomla.html library along with details on the JPane class.
Appendix F , Joomla! Utility Classes covers twenty Joomla! utility classes that perform many common tasks.
Appendix G , Request and Session Handling details the Joomla! request and session handling classes, including caching and routing.
Appendix H , XML Manifest File provides detailed information on the tags available for use in XML Manifest files.
To use this book effectively you need access to a Joomla! 1.5 installation. In order to run Joomla! 1.5 you need the following software: PHP 4.3 or higher (4.4.3 or greater is recommended), MySQL 3.23 or higher and Apache 1.3 or higher or an equivalent webserver.
In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.
Code in text is shown as follows: "We can include other contexts through the use of the include directive."
A block of code is set as follows:
[default] exten => s,1,Dial(Zap/1|30) exten => s,2,Voicemail(u100) exten => s,102,Voicemail(b100) exten => i,1,Voicemail(s0)
When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:
[default]
exten => s,1,Dial(Zap/1|30)
exten => s,2,Voicemail(u100)
exten => s,102,Voicemail(b100)
exten => i,1,Voicemail(s0)Any command-line input or output is written as follows:
# cp /usr/src/asterisk-addons/configs/cdr_mysql.conf.sample /etc/asterisk/cdr_mysql.conf
New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "clicking on the Next button moves you to the next screen".
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