3 Globals are evil. The original MediaWiki code relied on globals for processing
4 context far too often. MediaWiki development since then has been a story of
5 slowly moving context out of global variables and into objects. Storing
6 processing context in object member variables allows those objects to be reused
7 in a much more flexible way. Consider the elegance of:
9 # Generate the article HTML as if viewed by a web request
10 $article = new Article( Title::newFromText( $t ) );
15 # Save current globals
17 $oldArticle = $wgArticle;
20 $wgTitle = Title::newFromText( $t );
21 $wgArticle = new Article;
26 $wgArticle = $oldArticle
28 Some of the current MediaWiki developers have an idle fantasy that some day,
29 globals will be eliminated from MediaWiki entirely, replaced by a configuration
30 object which would be passed to constructors. Whether that would be an
31 efficient, convenient solution remains to be seen, but certainly PHP 5 makes
32 such object-oriented programming models easier than they were in previous
35 For the time being though, MediaWiki programmers will have to work in an
36 environment with some global context. At the time of writing (2008), 418 globals were
37 initialised on startup by MediaWiki. 304 of these were configuration settings,
38 which are defined in MainConfigSchema.php. There is no comprehensive
39 documentation for the remaining 114 globals, however some of the most important
40 ones are listed below. They are typically initialised either in index.php or in
44 Title object created from the request URL.
45 Use IContextSource::getTitle() instead.
48 OutputPage object for HTTP response.
49 Use IContextSource::getOutput() instead.
52 User object for the user associated with the current request.
53 Use IContextSource::getAuthority() instead.
56 Language object selected by user preferences.
57 Use IContextSource::getLanguage() instead.
60 WebRequest object, to get request data
61 Use IContextSource::getRequest() instead.