Developer hub



This is a high-level overview of the MediaWiki development process, including links to the key documents, resources and tools available to MediaWiki developers. It is written for experienced LAMP developers who have experience using MediaWiki.

For an introductory guide to developing MediaWiki, read how to become a MediaWiki hacker. For help installing or customizing MediaWiki, visit the Sysadmin hub. For help using MediaWiki, visit the User hub.

Overview
MediaWiki is written in the PHP programming language, with some supporting tools written in other languages. The software runs on various platforms, but is primarily developed for the LAMP platform. Various other tools (such as APC, memcached and LaTeX) are used to enhance the functionality or performance of MediaWiki.

The MediaWiki developers coordinate most of their work using online (or networked) tools and documents:
 * development discussion happens on various mailing lists and IRC channels. The main developer list is wikitech-l. The main developer IRC channel is #mediawiki.
 * The MediaWiki roadmap shows rough information about when major development work is scheduled.
 * bugs and issues are managed using Bugzilla at bugzilla.wikimedia.org.
 * code review is facilitated using the CodeReview MediaWiki extension at Special:Code/MediaWiki and follows the code review guidelines.
 * source code is managed using the Subversion revision control system.


 * documentation for developers is maintained in the Manual namespace on this wiki. A class reference (which is generated from the MediaWiki source code using doxygen) can be found at http://svn.wikimedia.org/doc.

Code, development and style

 * Development policy – an overview of key development policies.
 * Coding conventions – learn how to write PHP code in the MediaWiki style.
 * Security for developers – learn how to help keep MediaWiki secure.
 * Pre-commit_checklist – review this checklist before committing code.
 * Commit access – instructions on requesting commit access and committing code.

Debugging and testing

 * Bugs – an overview of bug tracking in the MediaWiki project.
 * How to debug – a guide to debugging MediaWiki.
 * Selenium Framework – learn to write UI tests for MediaWiki using Selenium.
 * Unit testing – learn to write unit tests for MediaWiki using PHPUnit.

Architecture

 * Manual:Code – an overview of the key parts of MediaWiki's source code.
 * Database layout – an overview of MediaWiki's database schemas.
 * Global object variables – a partial list of key global variables.
 * Localisation – learn about MediaWiki's internationalization system.
 * MediaWiki Class Reference – technical documentation generated from the MediaWiki source code. (Note: The class reference is a large, slow-to-load page.)

Sub-systems

 * API – MediaWiki's API provides direct, high-level access to the data contained in the MediaWiki databases.
 * Database access – an overview of using databases in MediaWiki, including a brief guide to the database abstraction layer.

Extending MediaWiki
There are five main extension points that allow developers to change or extend what MediaWiki can do. MediaWiki has been designed to allow for modification without changing the "core code". This makes it easy to update to a new version of MediaWiki without having to manually merge in old extension code changes.

The extension points are:
 * Hooks – every time a given event happens do something.
 * Parser Functions – create a new command like:
 * Skins – change the look and feel of MediaWiki.
 * Special Pages – add a new special page.
 * Tag Extensions – create a new tag like:

Help for extension developers

 * Manual:Extensions
 * Extensions FAQ
 * Category:Extensions – A (very incomplete) list of existing extensions
 * Extension Matrix – A better auto-generated list.
 * Manual:$wgExtensionFunctions

Help for skin developers

 * Manual:Skinning
 * Manual:Skin configuration