MediaWikiDoc:Code

Techniques: MediaWiki: Code

Where the Nav Links Come From

In SkinTemplate.php, function outputPage seems to be building a massive hierarchical array ($tpl) of all the various components needed to display a wiki page, which is then converted to HTML (etc.) by the code in the applicable (skin name).php file.

Significant lines for generating the navigation links would appear to be these:

$tpl->set( 'navigation_urls', $this->buildNavigationUrls() );
$tpl->set( 'nav_urls', $this->buildNavUrls() );

Both of these return arrays which are added to the $tpl array. Function buildNavigationUrls() uses $wgNavigationLinks as a source for its list of links. Function buildNavUrls(), however, has a hard-coded list; it's not clear what the relationship is between those two.

$wgNavigationLinks is defined in DefaultSettings.php, and presumably can be redefined in LocalSettings.php:

$wgNavigationLinks = array (
	array( 'text'=>'mainpage',	'href'=>'mainpage' ),
	array( 'text'=>'portal',	'href'=>'portal-url' ),
	array( 'text'=>'currentevents', 'href'=>'currentevents-url' ),
	array( 'text'=>'recentchanges', 'href'=>'recentchanges-url' ),
	array( 'text'=>'randompage',	'href'=>'randompage-url' ),
	array( 'text'=>'help', 		'href'=>'helppage' ),
	array( 'text'=>'sitesupport',	'href'=>'sitesupport-url' ),
);

Each of the strings (except "text" and "href") refers to a value which is settable via the wiki, e.g. the value of "mainpage" can be set by editing the contents of MediaWiki:mainpage.

How A Page is Built

(From Woozle 21:59, 15 Jun 2005 (EDT).)

• Everything obviously starts with index.php
• For the purpose of displaying a page (not saving changes or doing anything else), this calls $wgArticle->view(), in Article.php (line 699)
• $wgArticle->view() appears to be able to provide a few other formats besides the regular view (including difference engine and displaying redirections as subtitles), but I'm ignoring that for now
• $wgOut seems to be the object which accumulates text to be output. It is created in Setup.php:
  • $wgOut = new OutputPage();
• OutputPage() is defined in OutputPage.php
• After being created, $wgOut accumulates output via various class methods:
  • $wgOut->addWikiText(...)
  • $wgOut->addHTML(...)
  • $wgOut->addPrimaryWikiText() # Display content and save to parser cache
  • $wgOut->addWikiText() # Display content, don't attempt to save to parser cache
  • $wgOut->setPageTitle()
  • $wgOut->transformBuffer(); # Put link titles into the link cache
  • $wgOut->addMetaTags(); # Add link titles as META keywords
• ...and then it does these two lines:
  • $this->viewUpdates(); (found at line 1926 -- doesn't do much)
  • wfProfileOut( $fname );
• It's not clear whether the navbar has already been pulled in by the time we hit viewUpdates -- possibly transformBuffer does it? The comment makes it sound like that, but the name "transformBuffer" in that case is not very descriptive. The code in there should probably be examined.