ikiwiki/doc/users/jasonblevins.mdwn

[[!meta title="Jason Blevins"]]

I'm currently hosting a private ikiwiki for keeping research notes
which, with some patches and a plugin (below), will
convert inline LaTeX expressions to MathML.  I'm working towards a
patchset and instructions for others to do the same.

I've setup a test ikiwiki [here](http://xbeta.org/colab/) where I've
started keeping a few notes on my progress.  There is an example of
inline SVG on the homepage (note that the logo scales along with the
font size).  There are a few example mathematical expressions in the
[sandbox](http://xbeta.org/colab/sandbox/).  The MathML is generated
automatically from inline LaTeX expressions using an experimental
plugin I'm working on.

My (also MathML-enabled) homepage: <http://jblevins.org/> (still using
Blosxom...maybe one day I'll convert it to ikiwiki...)

Current ikiwki issues of interest:

 * [[bugs/recentchanges_feed_links]]
 * [[bugs/HTML_inlined_into_Atom_not_necessarily_well-formed]]
 * [[plugins/toc/discussion]]
 * [[todo/BibTeX]]
 * [[todo/svg]]
 * [[todo/Option_to_make_title_an_h1?]]
 * [[bugs/SVG_files_not_recognized_as_images]]

## Plugins

These plugins are experimental.  Use them at your own risk.  Read the
perldoc documentation for more details.  Patches and suggestions are
welcome.

 * [mdwn_itex][] - Works with the `mdwn` plugin to convert inline LaTeX
   expressions to MathML using `itex2MML`.

 * [h1title][] - If present, use the leading level 1 Markdown header to
   set the page title and remove it from the page body.

 * [code][] - Whole file and inline code snippet syntax highlighting
   via GNU Source-highlight.  The list of supported file extensions is
   configurable.  There is also some preliminary [documentation][code-doc].
   See the [FortranWiki](http://fortranwiki.org) for examples.

 * [metamail][] - a plugin for loading metadata from email-style
   headers at top of a file (e.g., `title: Page Title` or
   `date: November 2, 2008 11:14 EST`).

 * [pandoc][] - Markdown page processing via [Pandoc](http://johnmacfarlane.net/pandoc/) (a Haskell library for converting from one markup format to another).  LaTeX and
   reStructuredText are optional.

 * [path][] - Provides path-specific template conditionals such as
   `IS_HOMEPAGE` and `IN_DIR_SUBDIR`.

 [mdwn_itex]: http://code.jblevins.org/ikiwiki/plugins.git/plain/mdwn_itex.pm
 [h1title]: http://code.jblevins.org/ikiwiki/plugins.git/plain/h1title.pm
 [code]: http://code.jblevins.org/ikiwiki/plugins.git/plain/code.pm
 [code-doc]: http://code.jblevins.org/ikiwiki/plugins.git/plain/code.text
 [metamail]: http://code.jblevins.org/ikiwiki/plugins.git/plain/metamail.pm
 [pandoc]: http://code.jblevins.org/ikiwiki/plugins.git/plain/pandoc.pm
 [path]: http://code.jblevins.org/ikiwiki/plugins.git/plain/path.pm


## MathML and SVG support

So far, I've made some notes on sanitizing MathML and SVG via
htmlscrubber on the [[todo/svg]] todo item.

I've also worked out some content-negotiation issues.  First of all,
one needs to modify the default templates to use the
XHTML+MathML+SVG doctype (see e.g., this [patch][template-patch]).
For most browsers, the content type of the pages should be
`application/xhtml+xml`.  The solution is easy if you want to
just send `application/xhtml+xml` to everybody:
just change the content type of `.html` files across the board.

However, if you want to support browsers that don't accept
`application/xhtml+xml` (and those that will but say they
don't, such as IE with the MathPlayer plugin), then one
needs a `mod_rewrite` rule like the following:

    RewriteCond %{HTTP_ACCEPT} application\/xhtml\+xml [OR]
    RewriteCond %{HTTP_USER_AGENT} (W3C.*Validator|MathPlayer)
    RewriteRule \.html$ - [T=application/xhtml+xml]

This solves the problem of MathML and inline SVG in static pages
but some additional work is required for dynamically generated
pages, like page previews, that are generated by `ikiwiki.cgi`.
We need to allow `ikiwiki.cgi` to set the content type dynamically
based on the `HTTP_CONTENT_TYPE` environment variable
(e.g., with the following [patch][cgi-patch]).  Then, the following
rewrite rules can pass the correct content type to ikiwiki:

    RewriteCond %{HTTP_ACCEPT} application\/xhtml\+xml [OR]
    RewriteCond %{HTTP_USER_AGENT} (W3C.*Validator|MathPlayer)
    RewriteRule ikiwiki.cgi$ - [T=application/xhtml+xml]

One final critical issue is that a production-ready setup needs to
implement some sort of on-the-fly error handling.  If a user submits
an invalid LaTeX expression or SVG code (not malicious, just invalid)
and saves the page, then browsers like Firefox will halt processing of
the page, preventing any further viewing or editing.  A less than
optimal solution is to force users to preview the page before saving.
That way if someone introduces invalid XHTML then they can't save the
page in the first place (unless they post directly to the right URL).

 [template-patch]: http://xbeta.org/gitweb/?p=xbeta/ikiwiki.git;a=blobdiff;f=templates/page.tmpl;h=380ef699fa72223744eb5c1ee655fb79aa6bce5b;hp=9084ba7e11e92a10528b2ab12c9b73cf7b0f40a7;hb=416d5d1b15b94e604442e4e209a30dee4b77b684;hpb=ececf4fb8766a4ff7eff943b3ef600be81a0df49
 [cgi-patch]: http://xbeta.org/gitweb/?p=xbeta/ikiwiki.git;a=commitdiff;h=fa538c375250ab08f396634135f7d79fce2a9d36