Saturday, February 05, 2011

What Is a Component, Module, and Plug in?


 Components are mini-applications that integrate with the framework or CMS. They have their own specific functionality, their own database structures, and their own presentational aspects. Examples of components are a Web forms application suite, a photo gallery or document download system, or the Web Links component found in the default Joomla! installation. n Modules are presentational elements. They take information that already exists and present them in visual “packages” that you can place in your template in a flexible manner. Modules also help extend components by allowing the data from a component to also be presented visually. Examples of modules include a latest photo from the photo gallery or a slide show of the photos. The default Joomla! Install has a latest news module that extends the Content component to show a list of the latest articles added to a site. n Plugins are small portions of code that work behind the scenes to assist how something behaves. As a page in a site is loading, plugins will scan the page and, based upon what is being sent to the browser, act according to the instructions that it has been designed for or programmed to do. Example plugins might insert the code
from your analytics supplier such as from Google or Woopra, they might place a border or shadow around an item automatically, or they might be the editor that you use for editing your content.  Joomla! has a number of default plugins such as the e-mail cloak that stops e-mail addresses presented on your site from being read by spam bots.
The directory itself is set up so that individual extensions are grouped by the functionality they provide. A listing will generally contain information about an extension, what it does, and whether it is a module, plugin, or component. It will also list the developer’s name or company name, include the date it was added to the directory, and include the last date that the extension’s listing was updated by the developer along with links to download. Some developers include links to a demos, support options, or documentation.

The JED also allows users of extensions to rate and review them. An extension can be rated on a scale of 0 to 5, with 0 being unrated or low and 5 being excellent. Reviews are all read and approved by the JED team of editors before publishing. The analysis of reviews before publishing allow the JED editors to assure that the review follows the rules and guidelines that are published in the FAQ located on the JED site. As of the writing of this book, more than 6,000 extensions are available on the JED site, with new extensions added every day.
Tip
Extensions are a great way to bring your Web site to life with added functionality that improves your users’ experience. One thing to note is that if you install an extension and find that you don’t want to use it or it doesn’t supply the functionality that you need, you need to remember to uninstall it completely. Having outdated and unused extensions installed on your Web site can be a security risk. Also, it is good to keep a list of the extensions along with the version number of the extensions you are using on your site. It will allow you to be more easily informed if an extension needs updating. It is good practice to
sign up for any update notifications that a developer may send out to the users of their extensions and also periodically check the developer’s site for update or information. The vulnerable extension list (VEL) is a list of extensions that may have security issues that is updated as often as possible by the VEL team. A link to that list is shown at the top of the Announcements forum, and the list itself is located on the Official Documentation wiki

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