Mediawiki

Install

Install on Debian

MediaWiki is available as a regular package. This is the recommendation way to keep security patches up-to-date:

sudo apt install mediawiki

Install a 2nd wiki on Debian

On debian, the mediawiki installed with the package is installed in /var/lib/mediawiki. This folder contains many symlinks to the package files in /usr/share/mediawiki directories.

We can create a second mediawiki instance, but it needs some copy and clean up. Let's assume we want to create a second wiki instance at /var/lib/mediawiki-bis.

• We basically copy everything in /var/lib/mediawiki, preserving existing symlinks.
• We clean up folder Template:Cache.
• We clean up folder Template:Config.
• We clean up folder Template:Images.
• We clean up folder Template:Upload.
• We delete LocalSettings.php.
• We start installation again.
• Install LocalSettings.php in /etc/mediawiki and symlink to it

mkdir /var/lib/mediawiki-bis
cd /var/lib/mediawiki-bis
cp -rp /var/lib/mediawiki/* .
rm -rf cache/*
rm -rf config/*
rm -rf images/*
rm -rf upload/*
cp /var/lib/mediawiki/images/README images/
rm LocalSettings.php
# ... Run install via browser, and copy LocalSettings to /etc/mediawiki/LocalSettings-bis.php
ln -sf /etc/mediawiki/LocalSettings-bis.php LocalSettings.php

Troubleshoot

• If during install, script detects that a mediawiki instance is already running, just temporarily rename file /etc/mediawiki/LocalSettings.php.

Hints and Tips

Purge wiki page cache

When changing templates, purge the browser & mediawiki cache. To purge the cache of a single page, add &action=purge to the URL (see [1] for more)

Increase default font size

The easiest way is to add the following to wiki common stylesheet (MediaWiki:Common.css):

/***** Increase default text size ****/
#content {font-size: 1.2em}
body.page-Main_Page #content {font-size: inherit}

The second line overrides effect of first line so that the new font size does not apply to the Main Page.

There are in fact several ways to increase the font size. Using Opera's DragonFly debug environment (Ctrl-Shift-I), it is easy to see how the font size of a normal wiki text is computed (css is filtered for property font-size):

Computed Style
    font-size: 15.36px;

Inherited from div
#bodyContent {
    font-size: 0.8em
}

Inherited from div
#content {
    font-size: larger
}

Inherited from body
body {
    font-size: 1.0em
}

Inherited from html
html {
    font-size: 1.0em
}

Note that em refers to the size of the current font, after application of all inherited styles. In the case above it means that the size of a standard wiki text is not 0.8em as given by div#bodyContent, but well 16px * 1.0 * 1.0 * 1.2 * 0.8 = 15.36px.

One can edit any CSS property above to change the default size of the wiki text. We choose to edit #content so that it only affects the wiki text part (including first header).

Keyboard shortcuts

• Reference page in wikipedia
• Page explaining how to change keyboard shortcut using user custom stylesheet.
• Most frequently-used HTML access keys (default access-key shortcut is <Alt+Shift> for Firefox and <shift+Esc> for Opera):

Action	Key	Firefox
accesskey-edit	e	<Alt+Shift+e>
accesskey-mainpage	z	<Alt+Shift+z>
accesskey-preview	p	<Alt+Shift+p>
accesskey-save	s	<Alt+Shift+s>
accesskey-search	f	<Alt+Shift+f>

Access Restriction

See these pages for implementing access restriction in MediaWiki:

• A page that implement per-page access restriction [2].
• Another way to hide pages [3].
  • See sourceforge project.
• Yet another extension [4].
• Security problem with access restriction extension:
  • [5]
  • [6]
• Some information on how to create custom namespaces [7].

Miscellaneous

Page Special:Version

produces a complete list of all extensions installed on the wiki.

Troubleshooting

Fix templates that always produce {{{1}}}

Update

No longer an issue on recent MW apparently (at least >=1.27).

Templates in Mediawiki will fail if the parameters contains an equal sign. Consider for instance the template nb:

<div class="noborder">
{{{1}}}</div>

Let's enclose a <source> tag:

{{nb|<source lang=bash>echo Hello</source>}}

echo Hello

The fix is simply to prepend 1= to the parameter value:

{{nb|1=<source lang=bash>echo Hello</source>}}

echo Hello

Tag attributes not expanded in templates

To have tag attributes expanded in wiki templates (in particular when these attributes contain template parameters), use the special construction {{#tag:tagname|content|attr1=val1|attr2=val2}}. See also #tag magic word and bugzilla 61341 for more information.

This is used in template Template:Rawfiledownloadexample:

You can download file "{{{name}}}" below, just click this link: {{#tag:file|{{{name}}}|name={{{name}}}|tag=pre}}.
{{#tag:pre|{{{content}}}}}

The example

{{Rawfiledownloadexample|name=myfile.txt|content=Once upon a time
There was a Tag
Tag was clickable
And clicked it was}}

expands into to the following with action ?action=raw&templates=expand:

You can download file "myfile.sh" below, just click this link: <file|name="myfile.sh" tag="pre">myfile.sh</file>.
<pre>Once upon a time
There was a Tag
Tag was clickable
And clicked it was</pre>

Can't upload file

Error message:

Could not create directory mwstore://local-backend/local-public/ when Uploading.

The problem is due to wrong ownership / permission in mediawiki folder [8]:

sudo chown -R www-data /var/www/mediawiki

MediaWiki for developers

References

• Developer Hub.
• Manual:Extensions
• Manual:Developing_extensions
• Manual:Tag_extensions (writing extensions that provides new wiki tags)
• Parser functions
• How do I render wikitext in my extension ?
• Manual:RequestContext

Tips

• In 99% of cases, extensions just need to use the method recursiveTagParse of the parser instead of Parser::parse (apparently this function is not re-entrant).

Debugging

• Mediawiki - How to debug

To see PHP errors, add to LocalSettings.php (or can also edit php.ini or .htaccess Mediawiki - How to debug):

error_reporting( -1 );
ini_set( 'display_errors', 1 );

Globals

Some global variables defined by Mediawiki. Note that to use these variables, we must first declare them as global:

global $wgExtensionAssetsPath;

Name	Default	Description
$IP	MW_INSTALL_PATH env var	IP stands for Install Path. The variable holds the local file path to the base installation of your wiki.
$wgScriptPath	/wiki	The base URL path (in relation to DOCUMENT ROOT).
$wgExtensionAssetsPath	{$wgScriptPath}/extensions	URL to extensions directory. Used to provide a base URL for extension assets like extension-specific images and scripts. Note the difference between $IP/extensions (points to the extensions directory on the server filesystem) and $wgScriptPath/extensions (points to the URL of the extensions directory).

Modules

• ResourceLoader/Modules — This page lists modules that ship with MediaWiki core by default.

ResourceLoader

References

• ResourceLoader on MediaWiki
• Developing with ResourceLoader

Quick walkthrough, registering modules, etc.

• $wgResourceModules
• ResourceLoader class reference
• Migration guide for extension developers

Add a CSS style module

For instance, from Extension::Cite

$wgHooks['BeforePageDisplay'][] = 'wfCiteBeforePageDisplay';
$wgResourceModules['ext.rtlcite'] = array(
	'localBasePath' => __DIR__ . '/modules',
	'remoteExtPath' => 'Cite/modules'
	'styles' => 'ext.rtlcite.css',
	'position' => 'top',
);

function wfCiteBeforePageDisplay( $out, &$sk ) {
	$out->addModuleStyles( 'ext.rtlcite' );
	return true;
}

In the following example we add the module only if a tag is present

$wgHooks['ParserFirstCallInit'][] = 'onParserSetup';
$wgResourceModules['ext.fentt'] = array(
    // ...
);
static function onParserSetup( Parser $parser ) {
    $parser->setHook( 'fentt', 'renderFenTT' );
}

$module_added = false;
function renderFenTT( $input, array $args, Parser $parser, PPFrame $frame ) {
    global $module_added;
    if( ! $module_added ) {
        $parser->getOutput()->addModuleStyles('ext.fentt');
        self::$module_added = true;
    }
    // ...
}

Troubleshoot

• Module is listed in the <head> element, but corresponding CSS/JS does not appear in downloaded content

Try to register the module (add to $wgResourceModules) at global level (i.e. not in the hook handle function that calls $addModuleStyles).

Hooks

• $wgHooks['BeforePageDisplay'[]] — Allows last minute changes to the output page, e.g. adding of CSS or JavaScript by extensions.

Javascript

Modules

JavaScript files are, like CSS files, also evaluated in the order they are defined in the scripts array (file extension.json). [9]

If a module must export a global object, do:

// foo.js
var Foo = {
    sayHello: function ( $element ) {
        $element.append( '<p>Hello Module!</p>' );
    }
};
window.Foo = Foo;

If a module must wait that the document be completely loaded before executing, do:

// init.js
$( function () {
    // This code must not be executed before the document is loaded. 
    Foo.sayHello( $( '#hello' ) );
});

Export javascript libraries

Some tips.

• Javascript libraries must be loaded with the ResourceLoader.
• JS libraries are loaded asynchronously. Moreover the global context is not the default global context, but the one of the ResourceLoader. If a library must export symbol to global context, they must attach it to the window object:

window.myjslib = myjslib;

• Some libraries don't export to window, but does so like in node.js (see node.js — how exports and module.exports works). So they attach to an object module.exports If that's the case, we must export it ourselves.

In extension.json, we have:

    "ResourceModules": {
        "scripts": [ "myjslib.js", "myjslib.export.js" ]
    }

assuming that myjslib.js export to module.exports, we fix that in library myjslib.export.js:

// Let's export i18next correctly
window.myjslib = window.myjslib || module.exports;    // Don't export twice
$.myjslib = $.myjslib || module.exports;              // Alternatively we can attach to jQuery context
myjslib = $.myjslib;                                  // Export to default context

We must do this immediately after loading the library, because another library could overwrite module.exports.

ResourceLoader Core Modules

See ResourceLoader Core Modules.

These contains

• The mediawiki module
• The OOjs module
• The jQuery module and plugins

jQuery plugins are available as ResourceLoader module that can be added as a module dependency in extension.json (for instance module jquery.ui.button).

To make sure that a module is available, either add it as dependency, or use the code [10]:

mw.loader.using( ['mediawiki.util','mediawiki.Title'] ).then( function () {
    /* This callback is invoked as soon as the modules are available. */
} );

There is also an error callback:

mw.loader.using([ 'mediawiki.util', 'jquery.placeholder', 'jquery.spinner' ], function(){
    console.warn( 'Ready callback was executed.', arguments );
}, function(){
    console.warn( 'Error callback was executed.', arguments );
});

Passing information from PHP to Javascript

See https://www.mediawiki.org/wiki/ResourceLoader/Developing_with_ResourceLoader#Passing_information_from_PHP_to_Javascript.

• Store data in HTML.
• Or use OutputPage::AddJsConfigVars. Pay attention however that PHP parser code are not necessarily run each time a page is visited (eg. if using memcached). If the parser must transfer data to JS context, one solution is to generate inline javascript in <script> tag.

Run with jQuery support or in RL context

To run our inline script with jQuery support, use the ResourceLoader queue RLQ [11], [12]:

RLQ.push(function () {
    console.log('This runs with jQuery support', $);
});
// or
(window.RLQ=window.RLQ||[]).push(function(){
    $(function() { console.log("test") });
});

Note that this is only useful for inlined scripts. Script loaded with the ResourceLoader may always assume that jQuery is available (since MW 1.17).

Add an external script

More solutions on Stack Overflow. For external script, call addHeadItem:

# Add onBeforePageDisplay function to BeforePageDisplay Hook
$wgHooks['BeforePageDisplay'][] ='onBeforePageDisplay';

function onBeforePageDisplay( OutputPage &$out, Skin &$skin )
{
    $script = '<script type="text/javascript" src="https://example.com/javascript.js"></script>';
    $out->addHeadItem("itemName", $script);
    return true;
};

Be aware that the script will be loaded in the default context, which is not the same as the ResourceLoader context that contains all loaded RL modules. So this script will not have access to RL libraries. To get access, add a callback to the ResourceLoader queue (see previous section).

Extension template

The Manual:Developing_extensions page gives us the structure that all extensions must follow.

Several templates are available:

• cookiecutter-mediawiki-extension.
• Extension:BoilerPlate
• MWStew.

extension.json

Since MW 1.25, all extension comes with a description file extension.json. See Extension.json schema for the list of all possible entries.

Troubleshooting an extension

First reflexes

• Test extension in Chrome and Firefox.
• Open up the browser debug window (Ctrl-Shift-C) and check the Console for javascript errors, file not found. Check also the network tab.
• Try to load extension in an older version, and bisect the version where the extension fails.

• Look at the MediaWiki release note for breaking changes.

Attention points

• MW + cache sucks. If changing PHP code, better edit a test page, add one character and save. This will flush the cache easily.
• If changing JS code, then Shift+F5 in browser should refresh it.

Using foreign JS

• These are probably minified. It helps greatly to replace them with pretty-printed version (e.g. https://www.prettifyjs.net/)
• Insert console.log(...) statement to help debugging.

Example

PgnJS extension, migration to mw1.35

• Extension fails on MW 1.35
• Looking at MW 1.35 breaking changes, we see that jquery.ui.* have been removed. This is used in PgnJS extension.json.
• Open up Firefox/Chrome debugging interface (Ctrl+Shift+C).

• In Console, we see errors about Error: Unknown module: jquery.ui.core
• Changing "dependencies": [ "jquery.ui.core", "jquery.ui.widget" ] to "dependencies": [ "jquery.ui" ] fixes the problem.
• However we see we still get a deprecated warning.

Example 2

PgnJS extension, migration to latest PgnViewerJS

• We first create a static file example.html just to make sure that the apache server is configured correctly (no perm issue)

• This will gives the value of the path to use internally (PgnViewerJS expect this path in a variable __globalCustomDomain.

How-To

Add an extension stylesheet in HTML head element

The goal is to add a stylesheet <link> tag in the HTML <head> element, either ALWAYS or CONDITIONALLY, and/or STATIC link or DYNAMIC link (from page content).

<head>
  ...
  <link rel="stylesheet" href="..." />
  ...
</head>

Criteria

• Must work with recent MW version, and use stable API.
• Must be page-caching friendly.
• If link is added conditionally, avoid parsing twice the page content. Can we use some context information?

Relevant hooks

• https://www.mediawiki.org/wiki/Manual:Hooks/OutputPageBeforeHTML
• https://www.mediawiki.org/wiki/Manual:Hooks/BeforePageDisplay
• https://www.mediawiki.org/wiki/Manual:Hooks/ParserFirstCallInit

Relevant example extensions

• https://www.mediawiki.org/wiki/Category:HTML_head_extensions

list of extensions designed to modify information in the HTML <head> element

• https://www.mediawiki.org/wiki/Extension:CSS

For MW 1.16.x and above. Use hook RawPageViewBeforeOutput to sanitize CSS, and ParserFirstCallInit to add a head item with $parser->getOutput()->addHeadItem( $headItem );.

• https://www.mediawiki.org/wiki/Extension:NewPageCSS

For MW 1.16+. Use a ParserFirstCallInit hook, then add a <style> element using $wgParser->mOutput->addHeadItem when it encounters a <css> tag. Looks an excellent candidate for our stuff!

• Extension:AddScriptCss

Inserts <script> (i.e. Javascript) or <link> (i.e. CSS) code at the bottom of the page's head or within the page's body. Securely inserts arbitrary code to the page's head using <addtohead>.

For MW 1.10, 1.11. Likely too complex for our use. Insert a metatag as an HTML comment, which is then parsed again (via preg_match_all) in OutputPageBeforeHTML hook.

• Extension:Cite

Found simply by ... looking for .css files in MW extensions/ directory!

Uses hooks ParserFirstCallInit (to register parser hooks for Cite tags like <ref>) and BeforePageDisplay (to add modules, including the call to addModuleStyles). But... checking the page source it turns out that Cite css file is *always* loaded by the dynamic resource loader, even when the tag is not used on the page. Is that a problem?

Troubleshooting

• $parser->getOutput()->addHeadItem( "..." ) not working on mobile device.

It works on desktop, on my tablet, but not on my smartphone. Why?

The fix is to load the module with addModuleStyles()($modules), as done for instance in Extension:Cite

Questions

• On Wikimedia, there is a link at the bottom to toggle between mobile / desktop view. Handy to test a site in mobile mode. How can we get it installed? By upgrading to the latest MW? or installing Mobile extension

The Solution

if (defined('MEDIAWIKI')) {
    $wgHooks['ParserFirstCallInit'][] = 'MWFenTT::onParserFirstCallInit';

    $wgResourceModules['ext.FenTT'] = array(
	    'localBasePath' => __DIR__,
	    'remoteExtPath' => 'FenTT',
	    'styles'        => 'FenTT.css',
	    'position'      => 'top',
    );

    class MWFenTT {
        private static $css_module_added = false;

        static function onParserFirstCallInit( Parser $parser ) {
            // Register parser handler for tag <fentt>
            $parser->setHook( 'fentt', 'MWFenTT::renderFentt' )
        }

        static function renderFentt( $input, array $args, Parser $parser, PPFrame $frame ) {
            if( ! self::$css_module_added ) {
                // Tell ResourceLoader that we need our css module
                $parser->getOutput()->addModuleStyles( 'ext.FenTT' );
                self::$css_module_added = true;
            }
            return FenTT::renderFentt($input,$args);
        }
    }
}

Extensions

• MediaWiki GeSHi
• MediaWiki RawFile

MediaWiki for Mobile

References

• Category:Mobile
• Manual:Mobiles, tablets and responsive design
• Making MediaWiki Mobile Friendly

CSS

• To apply CSS to a mobile skin, edit MediaWiki:Mobile.css, the counterpart of MediaWiki:Common.css.

Extensions for Mobile

• Extension:MobileFrontend

See also Writing a MobileFrontend friendly ResourceLoader module

Administration

Delete a page permanently

This procedure allows for permanently deleting a page from the wiki database, including the whole history. After this, there will be no trace left of the content of that page, except for a trace in the delete log indicating the date when the page was deleted and the reason (if any given).

• First, as admin user, go to the page to delete.
• In the menu, select 'Delete', select and type in a reason, then click "Delete page".

From now on, the page is deleted, but history is still in the database. Deletion can be reverted by going to the delete log page (Special:Log/delete)

• On the wiki server, run the maintenance script named deleteArchivedRevisions.php. This will permanently delete the page history from the wiki db.

cd /var/lib/mediawiki/maintenance
php ./deleteArchivedRevisions.php --delete

Upload lots of file at once

Use local command importImages.php [13].

php maintenance/importImages.php --comment "Rubik's cube position, better perspective" /opt/www/daemenj/web/kiwi.noekeon.org/miki/rb png

Or to force a specific user:

sudo -u www-data php maintenance/importImages.php --comment "Rubik OLL cases, from http://www.cubewhiz.com/oll.php" tmp/