Solution Strategy

Developing Wikibase Repository through MediaWiki extensions

One of the main requirements of Wikibase is to make data available to MediaWiki applications. This makes it a natural choice to deliver the Wikibase Client (= data consumer) functionality as MediaWiki extensions. The same is not necessarily the case for the Wikibase Repository, the subsystem that provides and maintains the structured data. Wikibase Repository could have been developed independently of MediaWiki, yet it was decided to use MediaWiki like a web framework and add the functionality to store and maintain structured data through MediaWiki extensions.

This came with the following benefits:

• better compatibility with the rest of the Wikimedia ecosystem
• achieving a familiar Wikimedia user experience out of the box
• reduction of initial boilerplate code and basic features
• the original development team had extensive MediaWiki experience
• ability to easily have one application that is both a Wikibase Client and a Wikibase Repository

It also had negative consequences:

• hacks to make MediaWiki do things it was not originally designed to do
  • storing structured data in the same place Wikitext is stored
  • showing different content dependent on user settings (language)
• binding to multiple extension points (Hooks, API actions, Special Pages, ResourceLoader, ...) of MediaWiki makes for a confusing control flow going back and forth between it and the code within the WikibaseRepo extension, where traditional web frameworks usually have one clearly defined entry and exit point
• strong coupling to MediaWiki concepts (Title, ParserOutput, ...) slowing down development of features that aren't backed by MediaWiki (Termbox, Federated Properties)