Manual:Extensions/Installation and upgrade/en

Once installed, MediaWiki is ready to accept extensions. To add an extension follow these steps:

Before you start

Some extensions provide instructions designed for installation using Unix commands. You require shell access (SSH) to enter these commands listed on the extension help pages.
This page assumes your site settings are in a file called LocalSettings.php, but if you ase a different file, for instance in a wiki farm, the instructions should be equally relevant.

Download an extension

Get the file package

For each extension, read its documentation to find out about the appropriate download locations and methods. Common ways of downloading extensions include:

Extension Distributor helps you to select and download most of the popular extensions, although not all extension developers necessarily recommend it.
A list of extensions stored in the Wikimedia Git repository is located at git:mediawiki/extensions.
Some extensions are also available through:
1. bundles
2. Composer , a dependency manager for PHP libraries. Many extensions can or should be installed using Composer. Proceed to Composer/For extensions for more information.
3. package repositories
Some extensions don't use version control and are not recommended.

Add the package to the `/extensions` folder

Extensions are usually distributed as modular packages. They generally go in their own subdirectory of $IP /extensions/.

You can add the file folder manually or have it transferred automatically if you use something like Git or Composer.

Install an extension

Always check the requirements and instructions that come with each extension. The following summary applies to most extensions, but many extensions require different and/or additional steps to be taken.
Ensure that required permissions are set.
At the end of the LocalSettings.php file, add:
```
wfLoadExtension( 'ExtensionName' );
```
This line forces the PHP interpreter to read the extension file, and thereby make it accessible to MediaWiki. For an earlier installation method using require_once and how to migrate, see the instructions below.
Configure if required or wanted. Configuration settings should typically be added after including the extension. Again, check the extension's instructions for details.
You may be required to run a maintenance script, for instance to add the necessary database tables.
Done!

Possible issues

Some extensions can conflict with maintenance scripts, for example if they directly access $_SERVER (not recommended). In this case they can be wrapped in the conditional so maintenance scripts can still run.
```
if ( !$wgCommandLineMode ) {
wfLoadExtension ( 'ExtensionName' );
}
```
The maintenance script importDump.php will fail for any extension which requires customised namespaces which is included inside the conditional above such as Extension:Semantic MediaWiki , Extension:Page Forms .

Add multiple extensions to `wfLoadExtensions()`

Especially if you have a large number of extensions, it may be useful to add them as an array to wfLoadExtensions() (with plural -s) instead of adding them to separate instances of wfLoadExtension() (singular). For instance, to install Cite, ParserFunctions and SpamBlacklist, you could write:

wfLoadExtensions( [ 'Cite', 'ParserFunctions', 'SpamBlacklist' ] );

This method comes with one limitation, which is that you cannot point to custom file locations, as explained in this section.

Upgrade an extension

Some extensions require to be updated whenever you update MediaWiki, while others work with multiple versions.

To upgrade to a new version of an extension:

Download the new version of the extension
Replace all the extension files in the extensions/<ExtensionName> directory with the new files. Do not remove the extension configuration present in LocalSettings.php
If the extension requires changes to the MediaWiki database, you will need to run the update.php maintenance script. Most extensions will mention if this script needs to be run or not. (Perform backup of your data before executing the script). If you don't have command line access, you can also use the web updater.
Documentation for an extension usually tells you what else you need to do.

Uninstall

To uninstall the extension, remove the relevant lines from LocalSettings.php (wfLoadExtension with the extension's name as well as any possible lines for associated configuration settings).
Optionally, delete the file package from the /extensions folder.

Advanced

Use custom locations

This must be done before you load any extensions or skins from non-standard directory locations:

If you keep your extensions in a location different from $IP/extensions, you need to override $wgExtensionDirectory , or use the second parameter of wfLoadExtension(), to specify the directory in which to find the extension.

If one or more of your extensions are stored in additional locations, use the second parameter of wfLoadExtension() to specify the location of the .json file for each of those extensions.

wfLoadExtensions() (plural) always uses $wgExtensionDirectory and cannot be overridden.

$wgExtensionDirectory = '/some/path';
wfLoadExtension( 'FooBar' ); // Looks in $wgExtensionDirectory for /some/path/FooBar/extension.json
wfLoadExtension( 'Hello', '/some/other/path/HelloV2/Hello.json' ); // Looks for /some/other/path/HelloV2/Hello.json

If your skins are not in $IP/skins, you need to override the poorly named $wgStyleDirectory , or use the second parameter of wfLoadSkin(), to specify the directory in which to find the skin.

If one or more of your skins are stored in additional locations, use the second parameter of wfLoadSkin() to specify the location of the .json file for each of those skins.

wfLoadSkins() (plural) always uses $wgStyleDirectory and cannot be overridden.

$wgStyleDirectory = '/my/skins';
wfLoadSkins( [ 'BarBaz', 'BazBar' ] ); // Looks in $wgStyleDirectory for both /my/skins/BarBaz/skin.json and /my/skins/BazBar/skin.json
wfLoadSkin( 'BamBam', '/yet/another/path/BamBam/skin.json' ); // Looks for /yet/another/path/BamBam/skin.json

Migrate from require_once

Before MediaWiki 1.25, configuration for extensions and skins was done in a PHP file using the extension's or skin's name, for example MyExtension.php or MySkin.php. To install an extension with LocalSettings.php, you would use require_once to call this PHP file:

require_once "$IP/extensions/Hello/Hello.php";
require_once "$IP/extensions/FooBar/FooBar.php";
$wgFooBarEnable = true;
require_once "$IP/skins/Baz/Baz.php";
require_once "/tmp/extension/some/where/else/BarFoo/BarFoo.php";

If the extensions are recent enough to support the current registration system, you would convert this to:

wfLoadExtensions( [ 'Hello', 'FooBar' ] );
$wgFooBarEnable = true;
wfLoadSkin( 'Baz' );
wfLoadExtension( 'BarFoo', '/tmp/extension/some/where/else/BarFoo/extension.json' );

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