Eric Hartwell's InfoDabble

 
Welcome to Eric Hartwell's InfoDabble
About | Site Map
Home Tech Notes Apollo 17: Blue Marble Apollo 17 Flight Journal   Calendars About me  

HowTo: Use MediaWiki for Managing Apollo Transcripts

By Eric Hartwell - last updated March 29, 2006

As part of the research for my Apollo 17 project, I decided to prepare a definitive timeline/transcript of the mission:

For my first pass, I built a simple HTML table with time, speaker, and text from a single transcript. Then, as I started combining multiple sources, I switched to HTML defined term / definition syntax, with inline comments and later separate footnotes. As I added more and more sources, the HTML got larger, more complex, and harder to manage.

Data and Formatting

Eventually I decided to use a generic and extensible XML format. Any formatting desired can easily be applied using an XSLT style sheet:

Editing, Revising, Annotating

A proper reference needs sources identified, interpretations explained, and a revision history with audit trail. I stated to write a .NET web application with its own database, when I realized I already have a web application that does all that - MediaWiki.

MediaWiki stores its content as plain text, though MediaWiki and HTML markup is supported. The extension mechanism lets you add custom code to process custom markup. For this project, I built an extension to let me store the transcript text as XML but display it as formatted HTML/CSS using the XSLT transform:

Future project: Editing raw XML is problematic. MediaWiki also supports special page extensions, which means I can build a generic editing plug-in that uses the XML schema to control what can be input. It can even use XSL to provide WYSIWYG editing.

Chapters

The entire transcript is way too big to handle as a single unit. At the other extreme, there are way too many events to use a separate wiki page for each one.

Actually, what the transcript really needs is the Book_Title / Chapter_Name / Page_Name naming convention used in WikiBooks.

By default, MediaWiki disables subpages in the main namespace. For example, "Foo/Bar" is a page entitled "Foo/Bar" instead of "Bar" being a sub-page of "Foo". Subpages are useful as a means of expressing hierarchies in information. To enable subpages, add the following to LocalSettings.php:

# Enable subpages in main namespace
$wgNamespacesWithSubpages[0] = 1;

The Apollo Flight Journal divides the mission into chapters, sections, and sub-sections, such as "Day 1 - Launch - First Stage"; the transcript wiki can follow the same format, with one wiki page per sub-section. If the combined XML source is organized with the corresponding <chapter>, <section>, and <subsection> tags, then splitting out the individual wiki "pages" and reassembling them into a single document can be automated.

After some experimenting, I decided to use MediaWiki headers for each section, so I could leverage the wiki's indexing and linking features. The source for a typical wiki page looks like this:

<noinclude>{{:A17FJ Page Header}}</noinclude>
==Launch: Countdown==
<XmlTransform
xslname="AS17FlightTranscript.xsl">
 <section title="Countdown">
   <event met="-000:01:00">
      <quote who="LCC">Mark T minus 1 minute and counting.</quote>
</event>
  ... more XML ...   
</section>
</XmlTransform>
<noinclude>{{:A17FJ Disclaimer}}</noinclude>

  • {{:A17FJ Page Header}} tells MediaWiki to insert the contents of the wiki page A17FJ Page Header at the start of each page.

  • ==Launch: Countdown== tells MediaWiki to use "Launch: Countdown" as the display title for this page/section.

  • <XmlTransform ></XmlTransform> tells MediaWiki to use the XmlTransform extension to format the contents using the AS17FlightTranscript.xsl "image" XSL transformation.

  • {{:A17FJ Disclaimer}} tells MediaWiki to insert the contents of the wiki page A17FJ Disclaimer as a common page footer.

  • The <noinclude></noinclude> tags tell MediaWiki not to display the header and footer for each section when the sections are inserted into other pages.

Using subpages, the wikitext source for the Apollo 17 Flight Journal's Launch page looks like this:

<noinclude>{{:A17FJ Page Header}}</noinclude>
==Launch==
*[[/Countdown/]]
*[[/First Stage S-IC/]]
*[[/Second Stage S-II/]]
*[[/Third Stage S-IVB/]]

([[../Launch (all)/|Click here to view all sections on a single page]])
<noinclude>{{:A17FJ Disclaimer}}</noinclude>
[[Category:Apollo 17]]

MediaWiki supports Composite pages. The wikitext of a page may contain tags for the inclusion of component pages, which gives the user a choice between viewing the component pages separately or all together. To include a page you use the syntax for a template by adding {{ and preceed the name of the page for inclusion with a colon ":" to show that it is not the name of a template. The wikitext source for the Apollo 17 Flight Journal's Launch (all) page, which is about 65KB, looks like this:

<noinclude>{{:A17FJ Page Header}}</noinclude>
{{:Apollo 17 Flight Journal/Launch/Countdown}}
{{:Apollo 17 Flight Journal/Launch/First Stage S-IC}}
{{:Apollo 17 Flight Journal/Launch/Second Stage S-II}}
{{:Apollo 17 Flight Journal/Launch/Third Stage S-IVB}}
<noinclude>{{:A17FJ Disclaimer}}</noinclude>

The composite page has an integrated TOC and section numbering; the numbering is not reset for each component page. Edit history, recent changes, watching pages, and "what links here" work separately for the component pages and the composition page, not for the composite page.

In-Line Reference Information

The Apollo Flight Journal series includes in-line reference information to better explain what's happening in the timeline. This can be as simple as a diagram of the spacecraft cabin, or a much more detailed description of how the onboard computer works. Much of this information applies to all the Apollo missions, so using a single copy simplifies maintenance.

This is easily handled in MediaWiki by using pages with a common section. These can be considered as the text equivalent of a programming subroutine; a subtopic equally relevant for A as for B, can be put both in page A and in page B, by making it a separate page C, called as a template from A and B.

  • For readers reading both A and B, it is useful that the duplication is indicated by a message or a special lay-out; otherwise it is confusing and inconvenient. One can for example use Template:cs (talk, backlinks, edit):
  • (This section appears in several articles.)
     
  • After saving one ends up viewing the template page. For easy access to the calling pages it is convenient to link the called page to them (on a calling page one becomes a self-link). This may well be integrated in the message about the duplication. It is even more convenient than the two-step link as shown above.

Getting Fancy

As you might expect with such a widely used open source project, there are a number of user-developed extensions already available, some of which could be useful for this project:

  • Biblio: Citation manager
  • EasyTimeline: Graphical timelines
  • ScreenPlay Extension: Text-formatting add-on which allows screenwriters and hobbyists the ability to use MediaWiki as a screen writing tool.
  • Interwiki linking: By adding a prefix to another project, internal link style ("prefixed internal link style") can be used to link to a page of another project. For example, [[wikipedia:interWiki]] links to the wikipedia:interWiki article on the English Wikipedia.

References

Revision History

  • March 29, 2006 - initial version
Creative Commons License

Unless otherwise noted, this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License

 

Site Map | About Me