wikimedia/mediawiki-core

<?php

namespace MediaWiki\Settings;

use MediaWiki\MainConfigNames;

/**
 * Utility for loading site-specific settings in a multi-tenancy ("wiki farm" or "wiki family")
 * environment. See <https://www.mediawiki.org/wiki/Manual:Wiki_family>.
 *
 * This class is designed to be used before the initialization of MediaWiki is complete.
 *
 * @unstable
 */
class WikiFarmSettingsLoader {

    private SettingsBuilder $settingsBuilder;

    /**
     * @param SettingsBuilder $settingsBuilder
     */
    public function __construct( SettingsBuilder $settingsBuilder ) {
        $this->settingsBuilder = $settingsBuilder;
    }

    /**
     * Loads any site-specific settings in a multi-tenant (wiki-farm)
     * environment. The settings file is expected to be found in the
     * directory identified by the WikiFarmSettingsDirectory config
     * variable. If WikiFarmSettingsDirectory is not set, wiki-farm
     * mode is disabled, and no site-specific settings will be loaded.
     *
     * The name of the site-specific settings file is determined using
     * the MW_WIKI_NAME environment variable. The file extension is
     * given by WikiFarmSettingsExtension and defaults to "yaml".
     *
     * @unstable
     */
    public function loadWikiFarmSettings() {
        $config = $this->settingsBuilder->getConfig();

        $farmDir = $config->get( MainConfigNames::WikiFarmSettingsDirectory );
        $farmExt = $config->get( MainConfigNames::WikiFarmSettingsExtension );

        if ( !$farmDir ) {
            return;
        }

        $site = null;
        $wikiName = $this->getWikiNameConstant();
        if ( $wikiName !== null ) {
            // The MW_WIKI_NAME constant is used to control the target wiki when running CLI scripts.
            // Maintenance.php sets it to the value of the --wiki option.
            $site = $wikiName;
        } elseif ( isset( $_SERVER['MW_WIKI_NAME'] ) ) {
            // The MW_WIKI_NAME environment variable is used to set the target wiki
            // via web server configuration, e.g. using Apache's SetEnv directive.
            // For maintenance scripts, it may be set as an environment variable,
            // or by using the --wiki option.
            $site = $_SERVER['MW_WIKI_NAME'];
        } elseif ( isset( $_SERVER['WIKI_NAME'] ) ) {
            // In 1.38, experimental support for wiki farms was added using the
            // "WIKI_NAME" server variable. This has been changed to "MW_WIKI_NAME"
            // in 1.39.
            $site = $_SERVER['WIKI_NAME'];

            // NOTE: We can't use wfDeprecatedMsg here, MediaWiki hasn't been initialized yet.
            trigger_error(
                'The WIKI_NAME server variable has been deprecated since 1.39, ' .
                    'use MW_WIKI_NAME instead.'
            );
        }

        if ( !$site ) {
            return;
        }

        $path = "$farmDir/$site.$farmExt";
        if ( $this->settingsBuilder->fileExists( $path ) ) {
            $this->settingsBuilder->loadFile( $path );
        }
    }

    /**
     * Access MW_WIKI_NAME in a way that can be overridden by tests
     *
     * @return string|null
     */
    protected function getWikiNameConstant() {
        return defined( 'MW_WIKI_NAME' ) ? MW_WIKI_NAME : null;
    }

}