gitlabhq/doc/development/wikis.md

stage, group, info, description, title

stage	group	info	description	title
Plan	Knowledge	Any user with at least the Maintainer role can merge updates to this content. For details, see https://docs.gitlab.com/development/development_processes/#development-guidelines-review.	Development guidelines for Wikis	Wikis development guidelines

Wiki functionality in GitLab uses Git repositories as the storage backend and is accessed from the Rails app through Gitaly RPC calls.

You can access wikis through:

• The Web UI
• The REST API
• Git itself

Involved Gems

Some notable gems that are used for wikis are:

Component	Description	Gem name	GitLab project	Upstream project
gitlab	Markup renderer, depends on various other gems	gitlab-markup	gitlab-org/gitlab-markup	github/markup

Wiki rendering

When rendering wiki pages, we use a custom Banzai pipeline. This pipeline adds wiki-specific markup, such as the [[link]] syntax.

Model classes

The Wiki class is the main abstraction around a wiki repository. You must initialize it with a container, which can be either a Project or Group:

classDiagram
  Wiki --> ProjectWiki
  Wiki --> GroupWiki

  class Wiki {
    #container
    #repository
  }

  class ProjectWiki {
    #project → #container
  }

  class GroupWiki {
    #group → #container
  }

Some models wrap similar classes from Gitaly:

Rails Model	Gitaly Class
Wiki	Gitlab::Git::Wiki
WikiPage	Gitlab::Git::WikiPage, Gitlab::Git::WikiPageVersion
	Gitlab::Git::WikiFile

Only some data is persisted in the database:

Model	Description
WikiPage::Meta	Metadata for wiki pages
WikiPage::Slug	Current and previous slugs of wiki pages
ProjectRepository	Gitaly storage data for project wikis
GroupWikiRepository	Gitaly storage data for group wikis

Attachments

The web UI uploads attachments through the REST API, which stores the files as commits in the wiki repository.