Drupal modules and themes

Drupal core is designed to be modular with a system of "hooks" and "callbacks", which are accessed internally via an API.^[1] This design allows third-party contributed (often abbreviated to "contrib") modules and themes to extend or override Drupal's default behaviors without changing Drupal core's code.

Drupal's modular design, which isolates Drupal core's files from contributed module and themes, increases flexibility and security and allows Drupal administrators to cleanly upgrade to new releases of Drupal core without potentially overwriting their site's customizations. To maintain this separation, Drupal administrators are instructed to avoid altering Drupal core's software.

Contributed modules

Contributed Drupal modules offer a variety of features including image galleries, custom content types and content listings, WYSIWYG editors, private messaging, 3rd-party integration tools, and more. The Drupal website lists 3709 free modules (as of March 1, 2009), written and contributed to by the Drupal community.^[2][3][4]

• Content Construction Kit (CCK) allows site administrators to dynamically create content types. A content type describes any kind of information to be stored in the website's database. These may include, but are not limited to, events, invitations, reviews, articles, or products.

• Views facilitates the retrieval and presentation of content to site visitors.

The CCK API has been integrated into Drupal as a core module in the unreleased Drupal 7 branch, and Views (without its user interface) will follow at some point in the future.^[5]

Contributed themes

Contributed themes adapt or replace a Drupal site's default look and feel.

Drupal themes use standardized formats that may be generated by common third-party theme design engines. Many themes for Drupal are written in the PHPTemplate engine^[6] or, to a lesser extent, the XTemplate engine.^[7] Some templates use hard-coded PHP.

Although early versions of Drupal's theming system were criticized^[8] for being less design-oriented and more complicated than those for Mambo, Joomla! and Plone, the inclusion of the PHPTemplate and XTemplate engines in Drupal has addressed some of these concerns. The new Drupal 6 theming system utilizes a template engine in an attempt to further separate HTML/CSS from PHP. A new Drupal development module, Devel, provides assistance to theme authors who use Drupal 6.

Community contributed Drupal themes at the Drupal website are released under GPL license (free), and most of them are demonstrated at the Drupal Theme Garden.

Notes

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.