Extension:PageInCat

MediaWiki extensions manual

PageInCat Release status: stable
Implementation	Parser function
Description	Adds a parser function to test if the current page is in some category
Author(s)	Bawolfftalk
Latest version	2
MediaWiki	1.18+
Parameters $wgPageInCatUseAccuratePreview
Hooks used ParserFirstCallInit ParserClearState ParserAfterTidy EditPageGetPreviewText ParserBeforeInternalParse
Licence	GPLv2
Download	Download extension Git [?]: Browse repository (GitHub) Gerrit code review Git commit log Download source tarball
Translate the PageInCat extension if it is available at translatewiki.net

Warning:

On MediaWiki 1.27 and later (due to change 1846e2dc15e957c55). This extension might sometimes not account for categories that got added to the current page immediately after save.

What can this extension do?

This extension adds a parser function that is similar to the {{#ifexist:...}} function from extension:ParserFunctions. It works as follows {{#incat:Some category|what to do if current page is in category|what to do if current page is not in category}}. It also suports #incategory, #ifpageincat and #ifpageincategory.

Conditional category inclusion

Adding things like {{#incat:Foo||[[category:Foo]]}} (Page is a member of category Foo only if it is not a member of category Foo) is generally a bad idea (duh!). This could cause the page to alternate being in and not in the category. More generally, putting any sort of category link inside a {{#incat:...}} may cause unexpected behaviour since the extension can't tell if its in the category until after parsing the entire page. In general, for the purposes of {{#incat:...}}, we consider the categories present the first time parsing the page as the categories the page is in.

If this sort of situation is detected during a preview, the following warning is presented at the top of the page:

Warning: The category Some category was detected incorrectly by {{#incat:...}}, and as a result this preview may be incorrect. This can be caused by including categories inside of {{#incat:...}} statements, and may result in inconsistent display.

Download instructions

If you have an svn client, checkout http://svn.wikimedia.org/svnroot/mediawiki/trunk/extensions/PageInCat . Otherwise you will have to download the individual files from that link manually.

Download extension
Git ^[?]:

• Browse repository (GitHub)
• Gerrit code review
• Git commit log
• Download source tarball

Installation

Download thingy, put it in appropriate place in extensions directory, add line wfLoadExtension( 'PageInCat' ); (On old MW you may have to do require_once( "$IP/extensions/PageInCat/PageInCat.php" ); instead) to bottom of LocalSettings.php

This extension will work on MediaWiki 1.18 and later. (The 1.19 version on the download page will work with 1.18)

Configuration parameters

$wgPageInCatUseAccuratePreview

Defaults to true. Controls if to use more accurate previews (aka use the categories that are in the wiki-text you are previewing instead of the last saved revision). May cause previews to take twice as much time as they normally would (This includes previewing things not using #incat functions). If this is set to false, previews will often have {{#incat:..}} being evaluated incorrectly, but once the page is saved, they will be evaluated correctly.

$wgExpensiveParserFunctionLimit

Not directly a configuration parameter of this extension, but limits the number of times you can use #incat (and other expensive parser functions) in a page (Doing #incat twice for the same category only counts as one usage). This defaults to 100, which should be more than enough.

See also

• Extension:ParserFunctions (For more general conditional constructs)
• Extension:CategoryTests (Didn't know CategoryTests extension existed when I wrote this one. The main difference seems to be that PageInCat will always try to use categories from the current revision, while CategoryTests may sometimes use the categories from the previous revision, which could result in unexpected page content)
• Extension:CategoryFunctions