Extension:Highlight Links in Category

MediaWiki extensions manual

Highlight Links in Category Release status: stable
Implementation	User interface, MyWiki
Description	Adds a CSS class to links pointing to members of a category
Author(s)	Brent Laabs (BrentLaabstalk)
Latest version	0.9.0 (2021-05-29)
MediaWiki	1.25+
Database changes	No
License	MIT License
Download	GitHub: project page git repository URL [help ] commit history Note: No localisation updates are provided by translatewiki.net . readme repository
Example	https://allthetropes.org/
Parameters $wgHighlightLinksInCategory
Hooks used GetLinkColours

Highlight Links in Category is an extension that adds a CSS class to links pointing to members of a category.

For reporting an issue or a bug, please use Miraheze Phabricator.

Installation

• Download and place the file(s) in a directory called HighlightLinksInCategory in your extensions/ folder.
• Add the following code at the bottom of your LocalSettings.php file:

  wfLoadExtension( 'HighlightLinksInCategory' );
  

• Done – Navigate to Special:Version on your wiki to verify that the extension is successfully installed.

Configuration parameters

$wgHighlightLinksInCategory

This global is an array that configures which categories get an added CSS class. The keys are the Category names, which must include underscores instead of spaces. Do not include the Category: namespace. The value for each key is the CSS class you would like to add to that category. For example:

    $wgHighlightLinksInCategory = array(
        "Disambiguation_pages" => 'disambig',
        "Templates" => 'templates',
    );

If you want add more than one class, separate the class names with spaces, like

    $wgHighlightLinksInCategory = array( "My_Cat" => "class1 class2 class3" );

You can add as many of these as you want, but from a UX perspective it's probably not awesome to add 500 different style links.

If $wgHighlightLinksInCategory is not set or empty, this extension will do nothing. If you're running a wiki farm and need to turn it off on some wikis, set $wgHighlightLinksInCategory = null; using false could lead to incorrect behavior.

Styling

Simply add the styles you need for these links to MediaWiki:Common.css on your wiki. For example:

    a.disambig {
        color: rebeccapurple
    }
    a.templates {
        font-weight: bold;
        background-color: #efe;
    }

If you want one category to override another, you'll have to specify it with CSS.

    a.templates.disambig {
        font-weight: normal;
        background-color: transparent;
        color: rebeccapurple;
    }

Or alternatively, you could have defined the original a.templates rule as a.templates:not(.disambig) instead.

There's also the link icon approach:

    a.superlink {
        background-image: url(super.png);
        padding-left: 16px;
    }

User Toggles

An easy way to set up toggling this highlighting on or off is to make a Gadget with CSS in it. Yes, this is a personalization extension that outsources the personalization part to other extensions; I can still sleep at night.

How this works

Right after MediaWiki determines which linked pages exist (to make redlinks), it runs the GetLinkColours hook (see LinkHolderArray.php). As we have a list of all of the page ids which are linked on that page, we can run one database query to see which of these links are in the set of categories we want to highlight. Because the query only happens on an index of the categorylinks table, it's reasonably fast. Then CSS classes are assigned based on the result, using the configuration values the user sets in $wgHighlightLinksInCategory.

Explaining how CSS works is outside the scope of this document.

Known issues

• CSS styles are not added in Flow, because it doesn't appear to call the GetLinkColors hook there.