Gitit

Gitit is a wiki program written in Haskell. It uses HAppS for the web server and session state, git for storage, history, search, diffs, and merging, and pandoc for markup processing. Pages and uploaded files are stored in a git repository and may be modified either by using git's command-line tools or through the wiki's web interface. Pandoc's extended version of markdown is used as a markup language. Pages can be exported in a number of different formats, including LaTeX, RTF, OpenOffice ODT, and MediaWiki markup. Gitit can be configured to display TeX math (using jsMath) and highlighted source code (using highlighting-kate).

Getting started

Compiling and installing gitit

You'll need the GHC compiler and the cabal-install tool. GHC can be downloaded here. For cabal-install on *nix, follow the [quick install][] instructions.

[quick install]: http://hackage.haskell.org/trac/hackage/wiki/CabalInstall#Quick Installation on Unix [pcre]: http://www.pcre.org/

If you want the syntax highlighting feature, you need to make sure that pandoc is compiled with support for it. First, make sure your system has the [pcre][] library installed. Then:

cabal install pandoc -fhighlighting

You can skip this step if you don't care about highlighting support.

You can now install the latest release of gitit:

cabal update
cabal install gitit

To install a version of gitit checked out from the repository, change to the gitit directory and type:

cabal install

The cabal tool will automatically install all of the required haskell libraries. If all goes well, by the end of this process, the latest release of gitit will be installed in your local .cabal directory. You can check this by trying:

gitit --version

If that doesn't work, check to see that gitit is in your local cabal-install executable directory (usually ~/.cabal/bin). And make sure ~/.cabal/bin is in your system path.

Running gitit

To run gitit, you'll need git in your system path. Check this by doing

git --version

Switch to the directory where you want to run gitit. This should be a directory where you have write access, since two directories, static and wikidata, and a file, gitit-users, will be created here. To start gitit, just type:

gitit

If all goes well, gitit will do the following:

1. Create a git repository, wikidata, and add a default front page.
2. Create a static directory containing the scripts and CSS used by gitit.
3. Start a web server on port 5001.

Check that it worked: open a web browser and go to http://localhost:5001.

Configuration options

You can set some configuration options when starting gitit, using the option -f [filename]. A configuration file takes the following form:

Config {
repositoryPath  = "wikidata",
userFile        = "gitit-users",
staticDir       = "static",
wikiLogo        = Just "/img/logo.png",
wikiTitle       = "Wiki",
wikiFooter      = "Powered by Gitit\n<!-- Logo courtesy of http://flickr.com/photos/wolfhound/127936545/, licensed under Creative Commons Attribution license -->",
tableOfContents = False,
maxUploadSize   = 100000,
portNumber      = 5001,
passwordSalt    = "l91snthoae8eou2340987",
debugMode       = True,
frontPage       = "Front Page",
noEdit          = ["Help", "Front Page"],
noDelete        = ["Help", "Front Page"],
accessQuestion  = Just ("Enter the access code (to request an access code, contact me@somewhere.org):", ["abcd"])
}

• repositoryPath is the (relative) path of the git repository in which the wiki's pages will be stored. If it does not exist, gitit will create it on startup.

• gitit-users is a file containing user login information (with hashed passwords). If it does not exist, gitit will start with an empty list of users. Gitit will write a new gitit-users file on shutdown.

• staticDir is the (relative) path of a directory in which static content (javascript, CSS, images) is stored. If it does not exist, gitit will create it on startup.

• wikiLogo is either Nothing (no logo) or Just "/url/of/logo". By default, the logo is set to /img/logo.png, so the easiest way to change the logo is just to copy a new file to static/img/logo.png. Be sure to use an absolute URL.

• wikiTitle is the title that will be shown on the browser's title bar, together with the name of the page being viewed.

• wikiFooter is raw HTML that will be inserted in the footer of every page.

• tableOfContents is either False or True. If it is True, a table of contents (derived from the page's headers) will appear on each page.

• maxUploadSize (in bytes) sets a limit to the size of file uploads.

• portNumber is the number of the port on which the wiki will be served.

• passwordSalt is used to hash the passwords in the user database; you should change this to something unique if you use gitit in a production setting.

• debugMode is either True or False. If it is True, debug information will be printed to the console when gitit is running.

• frontPage is the name of the page that is designated as the "front" or "entrance" page of the wiki. Any page may be designated.

• noEdit is a list of pages that cannot be edited.

• noDelete is a list of pages that cannot be deleted.

• accessQuestion provides primitive access control. It is either Nothing, in which case anyone will be allowed to create an account and edit wiki pages, or Just (question, [answer1, answer2, ...]), where question is a prompt that will be displayed when a user tries to create an account, and answer1, answer2, ... are the valid responses. The user must provide a valid response in order to create an account.

Configuring gitit

The static directory

If there is no wiki page or uploaded file corresponding to a request, gitit always looks last in the static directory. So, for example, a file foo.jpg in the img subdirectory of the static directory will be accessible at the url /img/foo.jpg. Pandoc creates three subdirectories of static, css, img, and js, which include the icons, stylesheets, and javascripts it uses.

Changing the theme

To change the look of the wiki, modify screen.css in static/css. To change the look of printed pages, modify print.css.

Adding support for math

Gitit is designed to work with jsMath to display LaTeX math in HTML. Download jsMath and jsMath Image Fonts from the jsMath download page. You'll have two .zip archives. Unzip them both in the static/js directory (a new subdirectory, jsMath, will be created). You can test to see if math is working properly by clicking "help" on the top navigation bar and looking for the math example (the quadratic formula).

To write math on a wiki page, just enclose it in dollar signs, as in LaTeX:

Here is a formula:  $\frac{1}{\sqrt{c^2}}$

You can write display math by enclosing it in double dollar signs:

$$\frac{1}{\sqrt{c^2}}$$

Highlighted source code

If gitit was compiled against a version of pandoc that has highlighting support (see above), you can get highlighted source code by using delimited code blocks:

~~~ {.haskell .numberLines}
qsort []     = []
qsort (x:xs) = qsort (filter (< x) xs) ++ [x] ++
               qsort (filter (>= x) xs) 
~~~

To see what languages are available:

pandoc -v

Accessing the wiki via git

All the pages and uploaded files are stored in a git repository. By default, this lives in the wikidata directory (though this can be changed through configuration options). So you can interact with the wiki using git command line tools:

git clone ssh://my.server.edu/path/of/wiki/wikidata
cd wikidata
vim Front\ Page.page  # edit the page
git commit -m "Added message about wiki etiquette" Front\ Page.page
git push 

If you now look at the Front Page on the wiki, you should see your changes reflected there. Note that the pages all have the extension .page.

Wiki links and formatting

For instructions on editing pages and creating links, see the "Help" page.

Upgrading and _local

HAppS uses the _local subdirectory to make state persistent. Gitit does not rely on this persistence; the configuration and user database are read from files on startup. So, it is okay to delete the _local subdirectory. You may need to do this after you have upgraded to a new version of gitit, with a different AppState data structure, because the new gitit will not be able to read the old gitit's state.

Reporting bugs

There is no bug tracker as yet, so report bugs directly to the author, jgm at berkeley . edu

Acknowledgements

The visual layout is shamelessly borrowed from Wikipedia.

The code in Gitit/State.hs is based on http://hpaste.org/5957 by mightybyte, as revised by dbpatterson.

The stylesheets are influenced by Wikipedia's stylesheets and by the bluetrip CSS framework (see BLUETRIP-LICENSE). Some of the icons in img/icons come from bluetrip as well.