Gollum is a simple wiki system built on top of Git that powers GitHub Wikis.

Gollum wikis are simply Git repositories that adhere to a specific format. Gollum pages may be written in a variety of formats and can be edited in a number of ways depending on your needs. You can edit your wiki locally:

• With your favorite text editor or IDE (changes will be visible after committing).
• With the built-in web interface.
• With the Gollum Ruby API.

Gollum follows the rules of Semantic Versioning and uses TomDoc for inline documentation.

The best way to install Gollum is with RubyGems:

$ [sudo] gem install gollum

If you're installing from source, you can use Bundler to pick up all the gems:

$ bundle install

In order to use the various formats that Gollum supports, you will need to separately install the necessary dependencies for each format. You only need to install the dependencies for the formats that you plan to use.

• ASCIIDoc -- brew install asciidoc on mac or apt-get install -y asciidoc on Ubuntu
• Creole -- gem install creole
• Markdown -- gem install redcarpet
• GitHub Flavored Markdown -- gem install github-markdown
• Org -- gem install org-ruby
• Pod -- Pod::Simple::HTML comes with Perl >= 5.10. Lower versions should install Pod::Simple from CPAN.
• RDoc
• ReStructuredText -- easy_install docutils
• Textile -- gem install RedCloth
• MediaWiki -- gem install wikicloth

To view and edit your Gollum repository locally via the built in web interface, simply install the Gollum gem, navigate to your repository via the command line, and run the executable:

$ gollum

This will start up a web server running the Gollum frontend and you can view and edit your wiki at http://localhost:4567. To get help on the command line utility, you can run it like so:

$ gollum --help

Note that the gollum server will not run on Windows because of an issue with posix-spawn (which is used by Grit).

A Gollum repository's contents are designed to be human editable. Page content is written in page files and may be organized into directories any way you choose. Special footers can be created in footer files. Other content (images, PDFs, etc) may also be present and organized in the same way.

Page files may be written in any format supported by GitHub-Markup (except roff). The current list of formats and allowed extensions is:

• ASCIIDoc: .asciidoc
• Creole: .creole
• Markdown: .markdown, .mdown, .mkdn, .mkd, .md
• Org Mode: .org
• Pod: .pod
• RDoc: .rdoc
• ReStructuredText: .rest.txt, .rst.txt, .rest, .rst
• Textile: .textile
• MediaWiki: .mediawiki, .wiki

Gollum detects the page file format via the extension, so files must have one of the supported extensions in order to be converted.

Page file names may contain any printable UTF-8 character except space (U+0020) and forward slash (U+002F). If you commit a page file with any of these characters in the name it will not be accessible via the web interface.

Even though page files may be placed in any directory, there is still only a single namespace for page names, so all page files should have globally unique names regardless of where they are located in the repository.

The special page file Home.ext (where the extension is one of the supported formats) will be used as the entrance page to your wiki. If it is missing, an automatically generated table of contents will be shown instead.

Sidebar files allow you to add a simple sidebar to your wiki. Sidebar files are named _Sidebar.ext where the extension is one of the supported formats. Sidebars affect all pages in their directory and any subdirectories that do not have a sidebar file of their own.

Header files allow you to add a simple header to your wiki. Header files must be named _Header.ext where the extension is one of the supported formats. Like sidebars, headers affect all pages in their directory and any subdirectories that do not have a header file of their own.

Footer files allow you to add a simple footer to your wiki. Footer files must be named _Footer.ext where the extension is one of the supported formats. Like sidebars, footers affect all pages in their directory and any subdirectories that do not have a footer file of their own.

For security and compatibility reasons Gollum wikis may not contain custom CSS or JavaScript. These tags will be stripped from the converted HTML. See docs/sanitization.md for more details on what tags and attributes are allowed.

A variety of Gollum tags use a double bracket syntax. For example:

[[Link]]

Some tags will accept attributes which are separated by pipe symbols. For example:

[[Link|Page Title]]

In all cases, the first thing in the link is what is displayed on the page. So, if the tag is an internal wiki link, the first thing in the tag will be the link text displayed on the page. If the tag is an embedded image, the first thing in the tag will be a path to an image file. Use this trick to easily remember which order things should appear in tags.

Some formats, such as MediaWiki, support the opposite syntax:

[[Page Title|Link]]

To link to another Gollum wiki page, use the Gollum Page Link Tag.

[[Frodo Baggins]]

The above tag will create a link to the corresponding page file named Frodo-Baggins.ext where ext may be any of the allowed extension types. The conversion is as follows:

1. Replace any spaces (U+0020) with dashes (U+002D)
2. Replace any slashes (U+002F) with dashes (U+002D)

If you'd like the link text to be something that doesn't map directly to the page name, you can specify the actual page name after a pipe:

[[Frodo|Frodo Baggins]]

The above tag will link to Frodo-Baggins.ext using "Frodo" as the link text.

The page file may exist anywhere in the directory structure of the repository. Gollum does a breadth first search and uses the first match that it finds.

Here are a few more examples:

[[J. R. R. Tolkien]] -> J.-R.-R.-Tolkien.ext
[[Movies / The Hobbit]] -> Movies---The-Hobbit.ext
[[モルドール]] -> モルドール.ext

As a convenience, simple external links can be placed within brackets and they will be linked to the given URL with the URL as the link text. For example:

[[http://example.com]]

External links must begin with either "http://" or "https://". If you need something more flexible, you can resort to the link syntax in the page's underlying markup format.

For Gollum tags that operate on static files (images, PDFs, etc), the paths may be referenced as either relative, absolute, or external. Relative paths point to a static file relative to the page file within the directory structure of the Gollum repo (even though after conversion, all page files appear to be top level). These paths are NOT prefixed with a slash. For example:

gollum.pdf
docs/diagram.png

Absolute paths point to a static file relative to the Gollum repo's root, regardless of where the page file is stored within the directory structure. These paths ARE prefixed with a slash. For example:

/pdfs/gollum.pdf
/docs/diagram.png

External paths are full URLs. An external path must begin with either "http://" or "https://". For example:

http://example.com/pdfs/gollum.pdf
http://example.com/images/diagram.png

All of the examples in this README use relative paths, but you may use whatever works best in your situation.

To link to static files that are contained in the Gollum repository you should use the Gollum File Link Tag.

[[Gollum|gollum.pdf]]

The first part of the tag is the link text. The path to the file appears after the pipe.

To display images that are contained in the Gollum repository you should use the Gollum Image Tag. This will display the actual image on the page.

[[gollum.png]]

In addition to the simple format, there are a variety of options that you can specify between pipe delimiters.

To specify alt text, use the alt= option. Default is no alt text.

[[gollum.png|alt=Gollum and his precious wiki]]

To place the image in a frame, use the frame option. When combined with the alt= option, the alt text will be used as a caption as well. Default is no frame.

[[gollum.png|frame|alt=Gollum and his precious wiki]]

To specify the alignment of the image on the page, use the align= option. Possible values are left, center, and right. Default is left.

[[gollum.png|align=center]]

To float an image so that text flows around it, use the float option. When float is specified, only left and right are valid align options. Default is not floating. When floating is activated but no alignment is specified, default alignment is left.

[[gollum.png|float]]

To specify a max-width, use the width= option. Units must be specified in either px or em.

[[gollum.png|width=400px]]

To specify a max-height, use the height= option. Units must be specified in either px or em.

[[gollum.png|height=300px]]

Any of these options may be composed together by simply separating them with pipes.

If you need the literal text of a wiki or static link to show up in your final wiki page, simply preface the link with a single quote (like in LISP):

'[[Page Link]]
'[[File Link|file.pdf]]
'[[image.jpg]]

This is useful for writing about the link syntax in your wiki pages.

Gollum has a special tag to insert a table of contents (new in v2.1)

'[[_TOC_]]

This tag is case sensitive, use all upper case. The TOC tag can be inserted into the _Header, _Footer or _Sidebar files too.

There is also a wiki option :universal_toc which will display a table of contents at the top of all your wiki pages if it is enabled. The :universal_toc is not enabled by default. To set the option, add the option to the :wiki_options hash before starting the frontend app:

Precious::App.set(:wiki_options, {:universal_toc => true})

In page files you can get automatic syntax highlighting for a wide range of languages (courtesy of Pygments - must install separately) by using the following syntax:

```ruby
  def foo
    puts 'bar'
  end
```

The block must start with three backticks, at the beginning of a line or indented with any number of spaces or tabs. After that comes the name of the language that is contained by the block. The language must be one of the short name lexer strings supported by Pygments. See the list of lexers for valid options.

The block contents should be indented at the same level than the opening backticks. If the block contents are indented with an additional two spaces or one tab, then that whitespace will be ignored (this makes the blocks easier to read in plaintext).

The block must end with three backticks indented at the same level than the opening backticks.

Page files may contain mathematic equations in TeX syntax that will be nicely typeset into the expected output. A block-style equation is delimited by \[ and \]. For example:

\[ P(E) = {n \choose k} p^k (1-p)^{ n-k} \]

Inline equations are delimited by \( and \). These equations will appear inline with regular text. For example:

The Pythagorean theorem is \( a^2 + b^2 = c^2 \).

In order to get the mathematical equations rendering to work, you need the following binaries:

• LaText, TeTex or MacTex/BasicTeX (latex, dvips)
• ImageMagick (convert)
• Ghostscript (gs)

You may imbed sequence diagrams into your wiki page (rendered by WebSequenceDiagrams by using the following syntax:

{{{ blue-modern
  alice->bob: Test
  bob->alice: Test response
}}}

You can replace the string "blue-modern" with any supported style.

The Gollum API allows you to retrieve raw or formatted wiki content from a Git repository, write new content to the repository, and collect various meta data about the wiki as a whole.

Initialize the Gollum::Repo object:

# Require rubygems if necessary
require 'rubygems'

# Require the Gollum library
require 'gollum'

# Create a new Gollum::Wiki object by initializing it with the path to the
# Git repository.
wiki = Gollum::Wiki.new("my-gollum-repo.git")
# => <Gollum::Wiki>

By default, internal wiki links are all absolute from the root. To specify a different base path, you can specify the :base_path option:

wiki = Gollum::Wiki.new("my-gollum-repo.git", :base_path => "/wiki")

Get the latest version of the given human or canonical page name:

page = wiki.page('page-name')
# => <Gollum::Page>

page.raw_data
# => "# My wiki page"

page.formatted_data
# => "<h1>My wiki page</h1>"

page.format
# => :markdown

vsn = page.version
# => <Grit::Commit>

vsn.id
# => '3ca43e12377ea1e32ea5c9ce5992ec8bf266e3e5'

Get the footer (if any) for a given page:

page.footer
# => <Gollum::Page>

Get a list of versions for a given page:

vsns = wiki.page('page-name').versions
# => [<Grit::Commit, <Grit::Commit, <Grit::Commit>]

vsns.first.id
# => '3ca43e12377ea1e32ea5c9ce5992ec8bf266e3e5'

vsns.first.authored_date
# => Sun Mar 28 19:11:21 -0700 2010

Get a specific version of a given canonical page file:

wiki.page('page-name', '5ec521178e0eec4dc39741a8978a2ba6616d0f0a')

Get the latest version of a given static file:

file = wiki.file('asset.js')
# => <Gollum::File>

file.raw_data
# => "alert('hello');"

file.version
# => <Grit::Commit>

Get a specific version of a given static file:

wiki.file('asset.js', '5ec521178e0eec4dc39741a8978a2ba6616d0f0a')

Get an in-memory Page preview (useful for generating previews for web interfaces):

preview = wiki.preview_page("My Page", "# Contents", :markdown)
preview.formatted_data
# => "<h1>Contents</h1>"

Methods that write to the repository require a Hash of commit data that takes the following form:

commit = { :message => 'commit message',
           :name => 'Tom Preston-Werner',
           :email => 'tom@github.com' }

Write a new version of a page (the file will be created if it does not already exist) and commit the change. The file will be written at the repo root.

wiki.write_page('Page Name', :markdown, 'Page contents', commit)

Update an existing page. If the format is different than the page's current format, the file name will be changed to reflect the new format.

page = wiki.page('Page Name')
wiki.update_page(page, page.name, page.format, 'Page contents', commit)

To delete a page and commit the change:

wiki.delete_page(page, commit)

You can also run gollum with any rack-compatible server by placing this config.ru file inside your wiki repository. This allows you to utilize any Rack middleware like Rack::Auth, OmniAuth, etc.

#!/usr/bin/env ruby
require 'rubygems'
require 'gollum/frontend/app'

gollum_path = File.expand_path(File.dirname(__FILE__)) # CHANGE THIS TO POINT TO YOUR OWN WIKI REPO
Precious::App.set(:gollum_path, gollum_path)
Precious::App.set(:default_markup, :markdown) # set your favorite markup language
Precious::App.set(:wiki_options, {:universal_toc => false})
run Precious::App

Note that filenames on windows must not contain any of the following characters \ / : * ? " < > |. See this support article for details.

If you'd like to hack on Gollum, start by forking my repo on GitHub:

http://github.com/github/gollum

To get all of the dependencies, install the gem first. The best way to get your changes merged back into core is as follows:

1. Clone down your fork
2. Create a thoughtfully named topic branch to contain your change
3. Hack away
4. Add tests and make sure everything still passes by running rake
5. If you are adding new functionality, document it in the README
6. Do not change the version number, I will do that on my end
7. If necessary, rebase your commits into logical chunks, without errors
8. Push the branch up to GitHub
9. Send a pull request to the github/gollum project.

$ rake gemspec
$ gem build gollum.gemspec
$ gem push gollum-X.Y.Z.gem