Update to MediaWiki 1.25.1

11 files changed, 1353 insertions, 481 deletions

diff --git a/includes/site/CachingSiteStore.php b/includes/site/CachingSiteStore.php
new file mode 100644
index 00000000..9243f12b
--- /dev/null
+++ b/includes/site/CachingSiteStore.php
@@ -0,0 +1,195 @@
+<?php
+
+/**
+ * Represents the site configuration of a wiki.
+ * Holds a list of sites (ie SiteList), with a caching layer.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @since 1.25
+ *
+ * @file
+ * @ingroup Site
+ *
+ * @license GNU GPL v2+
+ * @author Jeroen De Dauw < jeroendedauw@gmail.com >
+ * @author Katie Filbert < aude.wiki@gmail.com >
+ */
+class CachingSiteStore implements SiteStore {
+
+	/**
+	 * @var SiteList|null
+	 */
+	private $sites = null;
+
+	/**
+	 * @var string|null
+	 */
+	private $cacheKey;
+
+	/**
+	 * @var int
+	 */
+	private $cacheTimeout;
+
+	/**
+	 * @var BagOStuff
+	 */
+	private $cache;
+
+	/**
+	 * @var SiteStore
+	 */
+	private $siteStore;
+
+	/**
+	 * @param SiteStore $siteStore
+	 * @param BagOStuff $cache
+	 * @param string|null $cacheKey
+	 * @param int $cacheTimeout
+	 */
+	public function __construct(
+		SiteStore $siteStore,
+		BagOStuff $cache,
+		$cacheKey = null,
+		$cacheTimeout = 3600
+	) {
+		$this->siteStore = $siteStore;
+		$this->cache = $cache;
+		$this->cacheKey = $cacheKey;
+		$this->cacheTimeout = $cacheTimeout;
+	}
+
+	/**
+	 * Constructs a cache key to use for caching the list of sites.
+	 *
+	 * This includes the concrete class name of the site list as well as a version identifier
+	 * for the list's serialization, to avoid problems when unserializing site lists serialized
+	 * by an older version, e.g. when reading from a cache.
+	 *
+	 * The cache key also includes information about where the sites were loaded from, e.g.
+	 * the name of a database table.
+	 *
+	 * @see SiteList::getSerialVersionId
+	 *
+	 * @return string The cache key.
+	 */
+	private function getCacheKey() {
+		if ( $this->cacheKey === null ) {
+			$type = 'SiteList#' . SiteList::getSerialVersionId();
+			$this->cacheKey = wfMemcKey( "sites/$type" );
+		}
+
+		return $this->cacheKey;
+	}
+
+	/**
+	 * @see SiteStore::getSites
+	 *
+	 * @since 1.25
+	 *
+	 * @return SiteList
+	 */
+	public function getSites() {
+		if ( $this->sites === null ) {
+			$this->sites = $this->cache->get( $this->getCacheKey() );
+
+			if ( !is_object( $this->sites ) ) {
+				$this->sites = $this->siteStore->getSites();
+
+				$this->cache->set( $this->getCacheKey(), $this->sites, $this->cacheTimeout );
+			}
+		}
+
+		return $this->sites;
+	}
+
+	/**
+	 * @see SiteStore::getSite
+	 *
+	 * @since 1.25
+	 *
+	 * @param string $globalId
+	 *
+	 * @return Site|null
+	 */
+	public function getSite( $globalId ) {
+		$sites = $this->getSites();
+
+		return $sites->hasSite( $globalId ) ? $sites->getSite( $globalId ) : null;
+	}
+
+	/**
+	 * @see SiteStore::saveSite
+	 *
+	 * @since 1.25
+	 *
+	 * @param Site $site
+	 *
+	 * @return bool Success indicator
+	 */
+	public function saveSite( Site $site ) {
+		return $this->saveSites( array( $site ) );
+	}
+
+	/**
+	 * @see SiteStore::saveSites
+	 *
+	 * @since 1.25
+	 *
+	 * @param Site[] $sites
+	 *
+	 * @return bool Success indicator
+	 */
+	public function saveSites( array $sites ) {
+		if ( empty( $sites ) ) {
+			return true;
+		}
+
+		$success = $this->siteStore->saveSites( $sites );
+
+		// purge cache
+		$this->reset();
+
+		return $success;
+	}
+
+	/**
+	 * Purges the internal and external cache of the site list, forcing the list
+	 * of sites to be reloaded.
+	 *
+	 * @since 1.25
+	 */
+	public function reset() {
+		// purge cache
+		$this->cache->delete( $this->getCacheKey() );
+		$this->sites = null;
+	}
+
+	/**
+	 * Clears the list of sites stored.
+	 *
+	 * @see SiteStore::clear()
+	 *
+	 * @return bool Success
+	 */
+	public function clear() {
+		$this->reset();
+
+		return $this->siteStore->clear();
+	}
+
+}
diff --git a/includes/site/DBSiteStore.php b/includes/site/DBSiteStore.php
new file mode 100644
index 00000000..f167584e
--- /dev/null
+++ b/includes/site/DBSiteStore.php
@@ -0,0 +1,345 @@
+<?php
+
+/**
+ * Represents the site configuration of a wiki.
+ * Holds a list of sites (ie SiteList), stored in the database.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @since 1.25
+ *
+ * @file
+ * @ingroup Site
+ *
+ * @license GNU GPL v2+
+ * @author Jeroen De Dauw < jeroendedauw@gmail.com >
+ */
+class DBSiteStore implements SiteStore {
+
+	/**
+	 * @var SiteList|null
+	 */
+	protected $sites = null;
+
+	/**
+	 * @var ORMTable
+	 */
+	protected $sitesTable;
+
+	/**
+	 * @since 1.25
+	 *
+	 * @param ORMTable|null $sitesTable
+	 */
+	public function __construct( ORMTable $sitesTable = null ) {
+		if ( $sitesTable === null ) {
+			$sitesTable = $this->newSitesTable();
+		}
+
+		$this->sitesTable = $sitesTable;
+	}
+
+	/**
+	 * @see SiteStore::getSites
+	 *
+	 * @since 1.25
+	 *
+	 * @return SiteList
+	 */
+	public function getSites() {
+		$this->loadSites();
+
+		return $this->sites;
+	}
+
+	/**
+	 * Returns a new Site object constructed from the provided ORMRow.
+	 *
+	 * @since 1.25
+	 *
+	 * @param ORMRow $siteRow
+	 *
+	 * @return Site
+	 */
+	protected function siteFromRow( ORMRow $siteRow ) {
+
+		$site = Site::newForType( $siteRow->getField( 'type', Site::TYPE_UNKNOWN ) );
+
+		$site->setGlobalId( $siteRow->getField( 'global_key' ) );
+
+		$site->setInternalId( $siteRow->getField( 'id' ) );
+
+		if ( $siteRow->hasField( 'forward' ) ) {
+			$site->setForward( $siteRow->getField( 'forward' ) );
+		}
+
+		if ( $siteRow->hasField( 'group' ) ) {
+			$site->setGroup( $siteRow->getField( 'group' ) );
+		}
+
+		if ( $siteRow->hasField( 'language' ) ) {
+			$site->setLanguageCode( $siteRow->getField( 'language' ) === ''
+				? null
+				: $siteRow->getField( 'language' )
+			);
+		}
+
+		if ( $siteRow->hasField( 'source' ) ) {
+			$site->setSource( $siteRow->getField( 'source' ) );
+		}
+
+		if ( $siteRow->hasField( 'data' ) ) {
+			$site->setExtraData( $siteRow->getField( 'data' ) );
+		}
+
+		if ( $siteRow->hasField( 'config' ) ) {
+			$site->setExtraConfig( $siteRow->getField( 'config' ) );
+		}
+
+		return $site;
+	}
+
+	/**
+	 * Get a new ORMRow from a Site object
+	 *
+	 * @since 1.25
+	 *
+	 * @param Site $site
+	 *
+	 * @return ORMRow
+	 */
+	protected function getRowFromSite( Site $site ) {
+		$fields = array(
+			// Site data
+			'global_key' => $site->getGlobalId(), // TODO: check not null
+			'type' => $site->getType(),
+			'group' => $site->getGroup(),
+			'source' => $site->getSource(),
+			'language' => $site->getLanguageCode() === null ? '' : $site->getLanguageCode(),
+			'protocol' => $site->getProtocol(),
+			'domain' => strrev( $site->getDomain() ) . '.',
+			'data' => $site->getExtraData(),
+
+			// Site config
+			'forward' => $site->shouldForward(),
+			'config' => $site->getExtraConfig(),
+		);
+
+		if ( $site->getInternalId() !== null ) {
+			$fields['id'] = $site->getInternalId();
+		}
+
+		return new ORMRow( $this->sitesTable, $fields );
+	}
+
+	/**
+	 * Fetches the site from the database and loads them into the sites field.
+	 *
+	 * @since 1.25
+	 */
+	protected function loadSites() {
+		$this->sites = new SiteList();
+
+		foreach ( $this->sitesTable->select() as $siteRow ) {
+			$this->sites[] = $this->siteFromRow( $siteRow );
+		}
+
+		// Batch load the local site identifiers.
+		$ids = wfGetDB( $this->sitesTable->getReadDb() )->select(
+			'site_identifiers',
+			array(
+				'si_site',
+				'si_type',
+				'si_key',
+			),
+			array(),
+			__METHOD__
+		);
+
+		foreach ( $ids as $id ) {
+			if ( $this->sites->hasInternalId( $id->si_site ) ) {
+				$site = $this->sites->getSiteByInternalId( $id->si_site );
+				$site->addLocalId( $id->si_type, $id->si_key );
+				$this->sites->setSite( $site );
+			}
+		}
+	}
+
+	/**
+	 * @see SiteStore::getSite
+	 *
+	 * @since 1.25
+	 *
+	 * @param string $globalId
+	 *
+	 * @return Site|null
+	 */
+	public function getSite( $globalId ) {
+		if ( $this->sites === null ) {
+			$this->sites = $this->getSites();
+		}
+
+		return $this->sites->hasSite( $globalId ) ? $this->sites->getSite( $globalId ) : null;
+	}
+
+	/**
+	 * @see SiteStore::saveSite
+	 *
+	 * @since 1.25
+	 *
+	 * @param Site $site
+	 *
+	 * @return bool Success indicator
+	 */
+	public function saveSite( Site $site ) {
+		return $this->saveSites( array( $site ) );
+	}
+
+	/**
+	 * @see SiteStore::saveSites
+	 *
+	 * @since 1.25
+	 *
+	 * @param Site[] $sites
+	 *
+	 * @return bool Success indicator
+	 */
+	public function saveSites( array $sites ) {
+		if ( empty( $sites ) ) {
+			return true;
+		}
+
+		$dbw = $this->sitesTable->getWriteDbConnection();
+
+		$dbw->startAtomic( __METHOD__ );
+
+		$success = true;
+
+		$internalIds = array();
+		$localIds = array();
+
+		foreach ( $sites as $site ) {
+			if ( $site->getInternalId() !== null ) {
+				$internalIds[] = $site->getInternalId();
+			}
+
+			$siteRow = $this->getRowFromSite( $site );
+			$success = $siteRow->save( __METHOD__ ) && $success;
+
+			foreach ( $site->getLocalIds() as $idType => $ids ) {
+				foreach ( $ids as $id ) {
+					$localIds[] = array( $siteRow->getId(), $idType, $id );
+				}
+			}
+		}
+
+		if ( $internalIds !== array() ) {
+			$dbw->delete(
+				'site_identifiers',
+				array( 'si_site' => $internalIds ),
+				__METHOD__
+			);
+		}
+
+		foreach ( $localIds as $localId ) {
+			$dbw->insert(
+				'site_identifiers',
+				array(
+					'si_site' => $localId[0],
+					'si_type' => $localId[1],
+					'si_key' => $localId[2],
+				),
+				__METHOD__
+			);
+		}
+
+		$dbw->endAtomic( __METHOD__ );
+
+		$this->reset();
+
+		return $success;
+	}
+
+	/**
+	 * Resets the SiteList
+	 *
+	 * @since 1.25
+	 */
+	public function reset() {
+		$this->sites = null;
+	}
+
+	/**
+	 * Clears the list of sites stored in the database.
+	 *
+	 * @see SiteStore::clear()
+	 *
+	 * @return bool Success
+	 */
+	public function clear() {
+		$dbw = $this->sitesTable->getWriteDbConnection();
+
+		$dbw->startAtomic( __METHOD__ );
+		$ok = $dbw->delete( 'sites', '*', __METHOD__ );
+		$ok = $dbw->delete( 'site_identifiers', '*', __METHOD__ ) && $ok;
+		$dbw->endAtomic( __METHOD__ );
+
+		$this->reset();
+
+		return $ok;
+	}
+
+	/**
+	 * @since 1.25
+	 *
+	 * @return ORMTable
+	 */
+	protected function newSitesTable() {
+		return new ORMTable(
+			'sites',
+			array(
+				'id' => 'id',
+
+				// Site data
+				'global_key' => 'str',
+				'type' => 'str',
+				'group' => 'str',
+				'source' => 'str',
+				'language' => 'str',
+				'protocol' => 'str',
+				'domain' => 'str',
+				'data' => 'array',
+
+				// Site config
+				'forward' => 'bool',
+				'config' => 'array',
+			),
+			array(
+				'type' => Site::TYPE_UNKNOWN,
+				'group' => Site::GROUP_NONE,
+				'source' => Site::SOURCE_LOCAL,
+				'data' => array(),
+
+				'forward' => false,
+				'config' => array(),
+				'language' => '',
+			),
+			'ORMRow',
+			'site_'
+		);
+	}
+
+}
diff --git a/includes/site/FileBasedSiteLookup.php b/includes/site/FileBasedSiteLookup.php
new file mode 100644
index 00000000..96544403
--- /dev/null
+++ b/includes/site/FileBasedSiteLookup.php
@@ -0,0 +1,139 @@
+<?php
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ *
+ * @license GNU GPL v2+
+ */
+
+/**
+ * Provides a file-based cache of a SiteStore. The sites are stored in
+ * a json file. (see docs/sitescache.txt regarding format)
+ *
+ * The cache can be built with the rebuildSitesCache.php maintenance script,
+ * and a MediaWiki instance can be setup to use this by setting the
+ * 'wgSitesCacheFile' configuration to the cache file location.
+ *
+ * @since 1.25
+ */
+class FileBasedSiteLookup implements SiteLookup {
+
+	/**
+	 * @var SiteList
+	 */
+	private $sites = null;
+
+	/**
+	 * @var string
+	 */
+	private $cacheFile;
+
+	/**
+	 * @param string $cacheFile
+	 */
+	public function __construct( $cacheFile ) {
+		$this->cacheFile = $cacheFile;
+	}
+
+	/**
+	 * @since 1.25
+	 *
+	 * @return SiteList
+	 */
+	public function getSites() {
+		if ( $this->sites === null ) {
+			$this->sites = $this->loadSitesFromCache();
+		}
+
+		return $this->sites;
+	}
+
+	/**
+	 * @param string $globalId
+	 *
+	 * @since 1.25
+	 *
+	 * @return Site|null
+	 */
+	public function getSite( $globalId ) {
+		$sites = $this->getSites();
+
+		return $sites->hasSite( $globalId ) ? $sites->getSite( $globalId ) : null;
+	}
+
+	/**
+	 * @return SiteList
+	 */
+	private function loadSitesFromCache() {
+		$data = $this->loadJsonFile();
+
+		$sites = new SiteList();
+
+		// @todo lazy initialize the site objects in the site list (e.g. only when needed to access)
+		foreach ( $data['sites'] as $siteArray ) {
+			$sites[] = $this->newSiteFromArray( $siteArray );
+		}
+
+		return $sites;
+	}
+
+	/**
+	 * @throws MWException
+	 * @return array see docs/sitescache.txt for format of the array.
+	 */
+	private function loadJsonFile() {
+		if ( !is_readable( $this->cacheFile ) ) {
+			throw new MWException( 'SiteList cache file not found.' );
+		}
+
+		$contents = file_get_contents( $this->cacheFile );
+		$data = json_decode( $contents, true );
+
+		if ( !is_array( $data ) || !is_array( $data['sites'] )
+			|| !array_key_exists( 'sites', $data )
+		) {
+			throw new MWException( 'SiteStore json cache data is invalid.' );
+		}
+
+		return $data;
+	}
+
+	/**
+	 * @param array $data
+	 *
+	 * @return Site
+	 */
+	private function newSiteFromArray( array $data ) {
+		$siteType = array_key_exists( 'type', $data ) ? $data['type'] : Site::TYPE_UNKNOWN;
+		$site = Site::newForType( $siteType );
+
+		$site->setGlobalId( $data['globalid'] );
+		$site->setForward( $data['forward'] );
+		$site->setGroup( $data['group'] );
+		$site->setLanguageCode( $data['language'] );
+		$site->setSource( $data['source'] );
+		$site->setExtraData( $data['data'] );
+		$site->setExtraConfig( $data['config'] );
+
+		foreach ( $data['identifiers'] as $identifier ) {
+			$site->addLocalId( $identifier['type'], $identifier['key'] );
+		}
+
+		return $site;
+	}
+
+}
diff --git a/includes/site/HashSiteStore.php b/includes/site/HashSiteStore.php
new file mode 100644
index 00000000..2c254721
--- /dev/null
+++ b/includes/site/HashSiteStore.php
@@ -0,0 +1,123 @@
+<?php
+/**
+ * In-memory implementation of SiteStore.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * In-memory SiteStore implementation, storing sites in an associative array.
+ *
+ * @author Daniel Kinzler
+ * @author Katie Filbert < aude.wiki@gmail.com >
+ *
+ * @since 1.25
+ * @ingroup Site
+ */
+class HashSiteStore implements SiteStore {
+
+	/**
+	 * @var Site[]
+	 */
+	private $sites = array();
+
+	/**
+	 * @param array $sites
+	 */
+	public function __construct( $sites = array() ) {
+		$this->saveSites( $sites );
+	}
+
+	/**
+	 * Saves the provided site.
+	 *
+	 * @since 1.25
+	 *
+	 * @param Site $site
+	 *
+	 * @return boolean Success indicator
+	 */
+	public function saveSite( Site $site ) {
+		$this->sites[$site->getGlobalId()] = $site;
+
+		return true;
+	}
+
+	/**
+	 * Saves the provided sites.
+	 *
+	 * @since 1.25
+	 *
+	 * @param Site[] $sites
+	 *
+	 * @return boolean Success indicator
+	 */
+	public function saveSites( array $sites ) {
+		foreach ( $sites as $site ) {
+			$this->saveSite( $site );
+		}
+
+		return true;
+	}
+
+	/**
+	 * Returns the site with provided global id, or null if there is no such site.
+	 *
+	 * @since 1.25
+	 *
+	 * @param string $globalId
+	 * @param string $source either 'cache' or 'recache'.
+	 *                       If 'cache', the values can (but not obliged) come from a cache.
+	 *
+	 * @return Site|null
+	 */
+	public function getSite( $globalId, $source = 'cache' ) {
+		if ( isset( $this->sites[$globalId] ) ) {
+			return $this->sites[$globalId];
+		} else {
+			return null;
+		}
+	}
+
+	/**
+	 * Returns a list of all sites. By default this site is
+	 * fetched from the cache, which can be changed to loading
+	 * the list from the database using the $useCache parameter.
+	 *
+	 * @since 1.25
+	 *
+	 * @param string $source either 'cache' or 'recache'.
+	 *                       If 'cache', the values can (but not obliged) come from a cache.
+	 *
+	 * @return SiteList
+	 */
+	public function getSites( $source = 'cache' ) {
+		return new SiteList( $this->sites );
+	}
+
+	/**
+	 * Deletes all sites from the database. After calling clear(), getSites() will return an empty
+	 * list and getSite() will return null until saveSite() or saveSites() is called.
+	 */
+	public function clear() {
+		$this->sites = array();
+
+		return true;
+	}
+
+}
diff --git a/includes/site/MediaWikiSite.php b/includes/site/MediaWikiSite.php
index 9711f042..95631f8e 100644
--- a/includes/site/MediaWikiSite.php
+++ b/includes/site/MediaWikiSite.php
@@ -116,7 +116,7 @@ class MediaWikiSite extends Site {
 			// Make sure the string is normalized into NFC (due to the bug 40017)
 			// but do nothing to the whitespaces, that should work appropriately.
 			// @see https://bugzilla.wikimedia.org/show_bug.cgi?id=40017
-			$pageName = UtfNormal::cleanUp( $pageName );
+			$pageName = UtfNormal\Validator::cleanUp( $pageName );
 
 			// Build the args for the specific call
 			$args = array(
@@ -137,7 +137,7 @@ class MediaWikiSite extends Site {
 
 			// Go on call the external site
 			// @todo we need a good way to specify a timeout here.
-			$ret = Http::get( $url );
+			$ret = Http::get( $url, array(), __METHOD__ );
 		}
 
 		if ( $ret === false ) {
diff --git a/includes/site/SiteExporter.php b/includes/site/SiteExporter.php
new file mode 100644
index 00000000..62f6ca3c
--- /dev/null
+++ b/includes/site/SiteExporter.php
@@ -0,0 +1,114 @@
+<?php
+
+/**
+ * Utility for exporting site entries to XML.
+ * For the output file format, see docs/sitelist.txt and docs/sitelist-1.0.xsd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @since 1.25
+ *
+ * @file
+ * @ingroup Site
+ *
+ * @license GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class SiteExporter {
+
+	/**
+	 * @var resource
+	 */
+	private $sink;
+
+	/**
+	 * @param resource $sink A file handle open for writing
+	 */
+	public function __construct( $sink ) {
+		if ( !is_resource( $sink ) || get_resource_type( $sink ) !== 'stream' ) {
+			throw new InvalidArgumentException( '$sink must be a file handle' );
+		}
+
+		$this->sink = $sink;
+	}
+
+	/**
+	 * Writes a <site> tag for each Site object in $sites, and encloses the entire list
+	 * between <sites> tags.
+	 *
+	 * @param Site[]|SiteList $sites
+	 */
+	public function exportSites( $sites ) {
+		$attributes = array(
+			'version' => '1.0',
+			'xmlns' => 'http://www.mediawiki.org/xml/sitelist-1.0/',
+		);
+
+		fwrite( $this->sink, XML::openElement( 'sites', $attributes ) . "\n" );
+
+		foreach ( $sites as $site ) {
+			$this->exportSite( $site );
+		}
+
+		fwrite( $this->sink, XML::closeElement( 'sites' ) . "\n" );
+		fflush( $this->sink );
+	}
+
+	/**
+	 * Writes a <site> tag representing the given Site object.
+	 *
+	 * @param Site $site
+	 */
+	private function exportSite( Site $site ) {
+		if ( $site->getType() !== Site::TYPE_UNKNOWN ) {
+			$siteAttr = array( 'type' => $site->getType() );
+		} else {
+			$siteAttr = null;
+		}
+
+		fwrite( $this->sink, "\t" . XML::openElement( 'site', $siteAttr ) . "\n" );
+
+		fwrite( $this->sink, "\t\t" . XML::element( 'globalid', null, $site->getGlobalId() ) . "\n" );
+
+		if ( $site->getGroup() !== Site::GROUP_NONE ) {
+			fwrite( $this->sink, "\t\t" . XML::element( 'group', null, $site->getGroup() ) . "\n" );
+		}
+
+		if ( $site->getSource() !== Site::SOURCE_LOCAL ) {
+			fwrite( $this->sink, "\t\t" . XML::element( 'source', null, $site->getSource() ) . "\n" );
+		}
+
+		if ( $site->shouldForward() ) {
+			fwrite( $this->sink, "\t\t" . XML::element( 'forward', null, '' ) . "\n" );
+		}
+
+		foreach ( $site->getAllPaths() as $type => $path ) {
+			fwrite( $this->sink, "\t\t" . XML::element( 'path', array( 'type' => $type ), $path ) . "\n" );
+		}
+
+		foreach ( $site->getLocalIds() as $type => $ids ) {
+			foreach ( $ids as $id ) {
+				fwrite( $this->sink, "\t\t" . XML::element( 'localid', array( 'type' => $type ), $id ) . "\n" );
+			}
+		}
+
+		//@todo: export <data>
+		//@todo: export <config>
+
+		fwrite( $this->sink, "\t" . XML::closeElement( 'site' ) . "\n" );
+	}
+
+}
diff --git a/includes/site/SiteImporter.php b/includes/site/SiteImporter.php
new file mode 100644
index 00000000..a05bad5d
--- /dev/null
+++ b/includes/site/SiteImporter.php
@@ -0,0 +1,263 @@
+<?php
+
+/**
+ * Utility for importing site entries from XML.
+ * For the expected format of the input, see docs/sitelist.txt and docs/sitelist-1.0.xsd.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @since 1.25
+ *
+ * @file
+ * @ingroup Site
+ *
+ * @license GNU GPL v2+
+ * @author Daniel Kinzler
+ */
+class SiteImporter {
+
+	/**
+	 * @var SiteStore
+	 */
+	private $store;
+
+	/**
+	 * @var callable|null
+	 */
+	private $exceptionCallback;
+
+	/**
+	 * @param SiteStore $store
+	 */
+	public function __construct( SiteStore $store ) {
+		$this->store = $store;
+	}
+
+	/**
+	 * @return callable
+	 */
+	public function getExceptionCallback() {
+		return $this->exceptionCallback;
+	}
+
+	/**
+	 * @param callable $exceptionCallback
+	 */
+	public function setExceptionCallback( $exceptionCallback ) {
+		$this->exceptionCallback = $exceptionCallback;
+	}
+
+	/**
+	 * @param string $file
+	 */
+	public function importFromFile( $file ) {
+		$xml = file_get_contents( $file );
+
+		if ( $xml === false ) {
+			throw new RuntimeException( 'Failed to read ' . $file . '!' );
+		}
+
+		$this->importFromXML( $xml );
+	}
+
+	/**
+	 * @param string $xml
+	 *
+	 * @throws InvalidArgumentException
+	 */
+	public function importFromXML( $xml ) {
+		$document = new DOMDocument();
+
+		$oldLibXmlErrors = libxml_use_internal_errors( true );
+		$ok = $document->loadXML( $xml, LIBXML_NONET );
+
+		if ( !$ok ) {
+			$errors = libxml_get_errors();
+			libxml_use_internal_errors( $oldLibXmlErrors );
+
+			foreach ( $errors as $error ) {
+				/** @var LibXMLError $error */
+				throw new InvalidArgumentException(
+					'Malformed XML: ' . $error->message . ' in line ' . $error->line
+				);
+			}
+
+			throw new InvalidArgumentException( 'Malformed XML!' );
+		}
+
+		libxml_use_internal_errors( $oldLibXmlErrors );
+		$this->importFromDOM( $document->documentElement );
+	}
+
+	/**
+	 * @param DOMElement $root
+	 */
+	private function importFromDOM( DOMElement $root ) {
+		$sites = $this->makeSiteList( $root );
+		$this->store->saveSites( $sites );
+	}
+
+	/**
+	 * @param DOMElement $root
+	 *
+	 * @return Site[]
+	 */
+	private function makeSiteList( DOMElement $root ) {
+		$sites = array();
+
+		// Old sites, to get the row IDs that correspond to the global site IDs.
+		// TODO: Get rid of internal row IDs, they just get in the way. Get rid of ORMRow, too.
+		$oldSites = $this->store->getSites();
+
+		$current = $root->firstChild;
+		while ( $current ) {
+			if ( $current instanceof DOMElement && $current->tagName === 'site' ) {
+				try {
+					$site = $this->makeSite( $current );
+					$key = $site->getGlobalId();
+
+					if ( $oldSites->hasSite( $key ) ) {
+						$oldSite = $oldSites->getSite( $key );
+						$site->setInternalId( $oldSite->getInternalId() );
+					}
+
+					$sites[$key] = $site;
+				} catch ( Exception $ex ) {
+					$this->handleException( $ex );
+				}
+			}
+
+			$current = $current->nextSibling;
+		}
+
+		return $sites;
+	}
+
+	/**
+	 * @param DOMElement $siteElement
+	 *
+	 * @return Site
+	 * @throws InvalidArgumentException
+	 */
+	public function makeSite( DOMElement $siteElement ) {
+		if ( $siteElement->tagName !== 'site' ) {
+			throw new InvalidArgumentException( 'Expected <site> tag, found ' . $siteElement->tagName );
+		}
+
+		$type = $this->getAttributeValue( $siteElement, 'type', Site::TYPE_UNKNOWN );
+		$site = Site::newForType( $type );
+
+		$site->setForward( $this->hasChild( $siteElement, 'forward' ) );
+		$site->setGlobalId( $this->getChildText( $siteElement, 'globalid' ) );
+		$site->setGroup( $this->getChildText( $siteElement, 'group', Site::GROUP_NONE ) );
+		$site->setSource( $this->getChildText( $siteElement, 'source', Site::SOURCE_LOCAL ) );
+
+		$pathTags = $siteElement->getElementsByTagName( 'path' );
+		for ( $i = 0; $i < $pathTags->length; $i++ ) {
+			$pathElement = $pathTags->item( $i );
+			$pathType = $this->getAttributeValue( $pathElement, 'type' );
+			$path = $pathElement->textContent;
+
+			$site->setPath( $pathType, $path );
+		}
+
+		$idTags = $siteElement->getElementsByTagName( 'localid' );
+		for ( $i = 0; $i < $idTags->length; $i++ ) {
+			$idElement = $idTags->item( $i );
+			$idType = $this->getAttributeValue( $idElement, 'type' );
+			$id = $idElement->textContent;
+
+			$site->addLocalId( $idType, $id );
+		}
+
+		//@todo: import <data>
+		//@todo: import <config>
+
+		return $site;
+	}
+
+	/**
+	 * @param DOMElement $element
+	 * @param $name
+	 * @param string|null|bool $default
+	 *
+	 * @return null|string
+	 * @throws MWException If the attribute is not found and no default is provided
+	 */
+	private function getAttributeValue( DOMElement $element, $name, $default = false ) {
+		$node = $element->getAttributeNode( $name );
+
+		if ( !$node ) {
+			if ( $default !== false ) {
+				return $default;
+			} else {
+				throw new MWException(
+					'Required ' . $name . ' attribute not found in <' . $element->tagName . '> tag'
+				);
+			}
+		}
+
+		return $node->textContent;
+	}
+
+	/**
+	 * @param DOMElement $element
+	 * @param string $name
+	 * @param string|null|bool $default
+	 *
+	 * @return null|string
+	 * @throws MWException If the child element is not found and no default is provided
+	 */
+	private function getChildText( DOMElement $element, $name, $default = false ) {
+		$elements = $element->getElementsByTagName( $name );
+
+		if ( $elements->length < 1 ) {
+			if ( $default !== false ) {
+				return $default;
+			} else {
+				throw new MWException(
+					'Required <' . $name . '> tag not found inside <' . $element->tagName . '> tag'
+				);
+			}
+		}
+
+		$node = $elements->item( 0 );
+		return $node->textContent;
+	}
+
+	/**
+	 * @param DOMElement $element
+	 * @param string $name
+	 *
+	 * @return bool
+	 * @throws MWException
+	 */
+	private function hasChild( DOMElement $element, $name ) {
+		return $this->getChildText( $element, $name, null ) !== null;
+	}
+
+	/**
+	 * @param Exception $ex
+	 */
+	private function handleException( Exception $ex ) {
+		if ( $this->exceptionCallback ) {
+			call_user_func( $this->exceptionCallback, $ex );
+		} else {
+			wfLogWarning( $ex->getMessage() );
+		}
+	}
+
+}
diff --git a/includes/site/SiteLookup.php b/includes/site/SiteLookup.php
new file mode 100644
index 00000000..610bf0b7
--- /dev/null
+++ b/includes/site/SiteLookup.php
@@ -0,0 +1,50 @@
+<?php
+
+/**
+ * Interface for service objects providing a lookup of Site objects.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @since 1.25
+ *
+ * @file
+ * @ingroup Site
+ *
+ * @license GNU GPL v2+
+ */
+interface SiteLookup {
+
+	/**
+	 * Returns the site with provided global id, or null if there is no such site.
+	 *
+	 * @since 1.25
+	 *
+	 * @param string $globalId
+	 *
+	 * @return Site|null
+	 */
+	public function getSite( $globalId );
+
+	/**
+	 * Returns a list of all sites.
+	 *
+	 * @since 1.25
+	 *
+	 * @return SiteList
+	 */
+	public function getSites();
+
+}
diff --git a/includes/site/SiteSQLStore.php b/includes/site/SiteSQLStore.php
index d1334680..d77f07be 100644
--- a/includes/site/SiteSQLStore.php
+++ b/includes/site/SiteSQLStore.php
@@ -28,468 +28,25 @@
  * @license GNU GPL v2+
  * @author Jeroen De Dauw < jeroendedauw@gmail.com >
  */
-class SiteSQLStore implements SiteStore {
-	/**
-	 * @since 1.21
-	 *
-	 * @var SiteList|null
-	 */
-	protected $sites = null;
-
-	/**
-	 * @var ORMTable
-	 */
-	protected $sitesTable;
-
-	/**
-	 * @var string|null
-	 */
-	private $cacheKey = null;
-
-	/**
-	 * @var int
-	 */
-	private $cacheTimeout = 3600;
+class SiteSQLStore extends CachingSiteStore {
 
 	/**
 	 * @since 1.21
+	 * @deprecated 1.25 Construct a SiteStore instance directly instead.
 	 *
 	 * @param ORMTable|null $sitesTable
+	 * @param BagOStuff|null $cache
 	 *
 	 * @return SiteStore
 	 */
-	public static function newInstance( ORMTable $sitesTable = null ) {
-		return new static( $sitesTable );
-	}
-
-	/**
-	 * Constructor.
-	 *
-	 * @since 1.21
-	 *
-	 * @param ORMTable|null $sitesTable
-	 */
-	protected function __construct( ORMTable $sitesTable = null ) {
-		if ( $sitesTable === null ) {
-			$sitesTable = $this->newSitesTable();
-		}
-
-		$this->sitesTable = $sitesTable;
-	}
-
-	/**
-	 * Constructs a cache key to use for caching the list of sites.
-	 *
-	 * This includes the concrete class name of the site list as well as a version identifier
-	 * for the list's serialization, to avoid problems when unserializing site lists serialized
-	 * by an older version, e.g. when reading from a cache.
-	 *
-	 * The cache key also includes information about where the sites were loaded from, e.g.
-	 * the name of a database table.
-	 *
-	 * @see SiteList::getSerialVersionId
-	 *
-	 * @return string The cache key.
-	 */
-	protected function getCacheKey() {
-		wfProfileIn( __METHOD__ );
-
-		if ( $this->cacheKey === null ) {
-			$type = 'SiteList#' . SiteList::getSerialVersionId();
-			$source = $this->sitesTable->getName();
-
-			if ( $this->sitesTable->getTargetWiki() !== false ) {
-				$source = $this->sitesTable->getTargetWiki() . '.' . $source;
-			}
-
-			$this->cacheKey = wfMemcKey( "$source/$type" );
-		}
-
-		wfProfileOut( __METHOD__ );
-		return $this->cacheKey;
-	}
-
-	/**
-	 * @see SiteStore::getSites
-	 *
-	 * @since 1.21
-	 *
-	 * @param string $source Either 'cache' or 'recache'
-	 *
-	 * @return SiteList
-	 */
-	public function getSites( $source = 'cache' ) {
-		wfProfileIn( __METHOD__ );
-
-		if ( $source === 'cache' ) {
-			if ( $this->sites === null ) {
-				$cache = wfGetMainCache();
-				$sites = $cache->get( $this->getCacheKey() );
-
-				if ( is_object( $sites ) ) {
-					$this->sites = $sites;
-				} else {
-					$this->loadSites();
-				}
-			}
-		}
-		else {
-			$this->loadSites();
-		}
-
-		wfProfileOut( __METHOD__ );
-		return $this->sites;
-	}
-
-	/**
-	 * Returns a new Site object constructed from the provided ORMRow.
-	 *
-	 * @since 1.21
-	 *
-	 * @param ORMRow $siteRow
-	 *
-	 * @return Site
-	 */
-	protected function siteFromRow( ORMRow $siteRow ) {
-		wfProfileIn( __METHOD__ );
-
-		$site = Site::newForType( $siteRow->getField( 'type', Site::TYPE_UNKNOWN ) );
-
-		$site->setGlobalId( $siteRow->getField( 'global_key' ) );
-
-		$site->setInternalId( $siteRow->getField( 'id' ) );
-
-		if ( $siteRow->hasField( 'forward' ) ) {
-			$site->setForward( $siteRow->getField( 'forward' ) );
-		}
-
-		if ( $siteRow->hasField( 'group' ) ) {
-			$site->setGroup( $siteRow->getField( 'group' ) );
-		}
-
-		if ( $siteRow->hasField( 'language' ) ) {
-			$site->setLanguageCode( $siteRow->getField( 'language' ) === ''
-				? null
-				: $siteRow->getField( 'language' )
-			);
-		}
-
-		if ( $siteRow->hasField( 'source' ) ) {
-			$site->setSource( $siteRow->getField( 'source' ) );
-		}
-
-		if ( $siteRow->hasField( 'data' ) ) {
-			$site->setExtraData( $siteRow->getField( 'data' ) );
-		}
-
-		if ( $siteRow->hasField( 'config' ) ) {
-			$site->setExtraConfig( $siteRow->getField( 'config' ) );
-		}
-
-		wfProfileOut( __METHOD__ );
-		return $site;
-	}
-
-	/**
-	 * Get a new ORMRow from a Site object
-	 *
-	 * @since 1.22
-	 *
-	 * @param Site $site
-	 *
-	 * @return ORMRow
-	 */
-	protected function getRowFromSite( Site $site ) {
-		$fields = array(
-			// Site data
-			'global_key' => $site->getGlobalId(), // TODO: check not null
-			'type' => $site->getType(),
-			'group' => $site->getGroup(),
-			'source' => $site->getSource(),
-			'language' => $site->getLanguageCode() === null ? '' : $site->getLanguageCode(),
-			'protocol' => $site->getProtocol(),
-			'domain' => strrev( $site->getDomain() ) . '.',
-			'data' => $site->getExtraData(),
-
-			// Site config
-			'forward' => $site->shouldForward(),
-			'config' => $site->getExtraConfig(),
-		);
-
-		if ( $site->getInternalId() !== null ) {
-			$fields['id'] = $site->getInternalId();
-		}
-
-		return new ORMRow( $this->sitesTable, $fields );
-	}
-
-	/**
-	 * Fetches the site from the database and loads them into the sites field.
-	 *
-	 * @since 1.21
-	 */
-	protected function loadSites() {
-		wfProfileIn( __METHOD__ );
-
-		$this->sites = new SiteList();
-
-		foreach ( $this->sitesTable->select() as $siteRow ) {
-			$this->sites[] = $this->siteFromRow( $siteRow );
-		}
-
-		// Batch load the local site identifiers.
-		$ids = wfGetDB( $this->sitesTable->getReadDb() )->select(
-			'site_identifiers',
-			array(
-				'si_site',
-				'si_type',
-				'si_key',
-			),
-			array(),
-			__METHOD__
-		);
-
-		foreach ( $ids as $id ) {
-			if ( $this->sites->hasInternalId( $id->si_site ) ) {
-				$site = $this->sites->getSiteByInternalId( $id->si_site );
-				$site->addLocalId( $id->si_type, $id->si_key );
-				$this->sites->setSite( $site );
-			}
-		}
-
-		$cache = wfGetMainCache();
-		$cache->set( $this->getCacheKey(), $this->sites, $this->cacheTimeout );
-
-		wfProfileOut( __METHOD__ );
-	}
-
-	/**
-	 * @see SiteStore::getSite
-	 *
-	 * @since 1.21
-	 *
-	 * @param string $globalId
-	 * @param string $source
-	 *
-	 * @return Site|null
-	 */
-	public function getSite( $globalId, $source = 'cache' ) {
-		wfProfileIn( __METHOD__ );
-
-		$sites = $this->getSites( $source );
-
-		wfProfileOut( __METHOD__ );
-		return $sites->hasSite( $globalId ) ? $sites->getSite( $globalId ) : null;
-	}
-
-	/**
-	 * @see SiteStore::saveSite
-	 *
-	 * @since 1.21
-	 *
-	 * @param Site $site
-	 *
-	 * @return bool Success indicator
-	 */
-	public function saveSite( Site $site ) {
-		return $this->saveSites( array( $site ) );
-	}
-
-	/**
-	 * @see SiteStore::saveSites
-	 *
-	 * @since 1.21
-	 *
-	 * @param Site[] $sites
-	 *
-	 * @return bool Success indicator
-	 */
-	public function saveSites( array $sites ) {
-		wfProfileIn( __METHOD__ );
-
-		if ( empty( $sites ) ) {
-			wfProfileOut( __METHOD__ );
-			return true;
-		}
-
-		$dbw = $this->sitesTable->getWriteDbConnection();
-
-		$dbw->startAtomic( __METHOD__ );
-
-		$success = true;
-
-		$internalIds = array();
-		$localIds = array();
-
-		foreach ( $sites as $site ) {
-			if ( $site->getInternalId() !== null ) {
-				$internalIds[] = $site->getInternalId();
-			}
-
-			$siteRow = $this->getRowFromSite( $site );
-			$success = $siteRow->save( __METHOD__ ) && $success;
-
-			foreach ( $site->getLocalIds() as $idType => $ids ) {
-				foreach ( $ids as $id ) {
-					$localIds[] = array( $siteRow->getId(), $idType, $id );
-				}
-			}
-		}
-
-		if ( $internalIds !== array() ) {
-			$dbw->delete(
-				'site_identifiers',
-				array( 'si_site' => $internalIds ),
-				__METHOD__
-			);
-		}
-
-		foreach ( $localIds as $localId ) {
-			$dbw->insert(
-				'site_identifiers',
-				array(
-					'si_site' => $localId[0],
-					'si_type' => $localId[1],
-					'si_key' => $localId[2],
-				),
-				__METHOD__
-			);
+	public static function newInstance( ORMTable $sitesTable = null, BagOStuff $cache = null ) {
+		if ( $cache === null ) {
+			$cache = wfGetMainCache();
 		}
 
-		$dbw->endAtomic( __METHOD__ );
+		$siteStore = new DBSiteStore();
 
-		// purge cache
-		$this->reset();
-
-		wfProfileOut( __METHOD__ );
-		return $success;
+		return new static( $siteStore, $cache );
 	}
 
-	/**
-	 * Purges the internal and external cache of the site list, forcing the list
-	 * of sites to be re-read from the database.
-	 *
-	 * @since 1.21
-	 */
-	public function reset() {
-		wfProfileIn( __METHOD__ );
-		// purge cache
-		$cache = wfGetMainCache();
-		$cache->delete( $this->getCacheKey() );
-		$this->sites = null;
-
-		wfProfileOut( __METHOD__ );
-	}
-
-	/**
-	 * Clears the list of sites stored in the database.
-	 *
-	 * @see SiteStore::clear()
-	 *
-	 * @return bool Success
-	 */
-	public function clear() {
-		wfProfileIn( __METHOD__ );
-		$dbw = $this->sitesTable->getWriteDbConnection();
-
-		$dbw->startAtomic( __METHOD__ );
-		$ok = $dbw->delete( 'sites', '*', __METHOD__ );
-		$ok = $dbw->delete( 'site_identifiers', '*', __METHOD__ ) && $ok;
-		$dbw->endAtomic( __METHOD__);
-
-		$this->reset();
-
-		wfProfileOut( __METHOD__ );
-		return $ok;
-	}
-
-	/**
-	 * @since 1.21
-	 *
-	 * @return ORMTable
-	 */
-	protected function newSitesTable() {
-		return new ORMTable(
-			'sites',
-			array(
-				'id' => 'id',
-
-				// Site data
-				'global_key' => 'str',
-				'type' => 'str',
-				'group' => 'str',
-				'source' => 'str',
-				'language' => 'str',
-				'protocol' => 'str',
-				'domain' => 'str',
-				'data' => 'array',
-
-				// Site config
-				'forward' => 'bool',
-				'config' => 'array',
-			),
-			array(
-				'type' => Site::TYPE_UNKNOWN,
-				'group' => Site::GROUP_NONE,
-				'source' => Site::SOURCE_LOCAL,
-				'data' => array(),
-
-				'forward' => false,
-				'config' => array(),
-				'language' => '',
-			),
-			'ORMRow',
-			'site_'
-		);
-	}
-
-}
-
-/**
- * @deprecated since 1.21
- */
-class Sites extends SiteSQLStore {
-
-	/**
-	 * Factory for creating new site objects.
-	 *
-	 * @since 1.21
-	 * @deprecated since 1.21
-	 *
-	 * @param string|bool $globalId
-	 *
-	 * @return Site
-	 */
-	public static function newSite( $globalId = false ) {
-		$site = new Site();
-
-		if ( $globalId !== false ) {
-			$site->setGlobalId( $globalId );
-		}
-
-		return $site;
-	}
-
-	/**
-	 * @deprecated since 1.21
-	 * @return SiteStore
-	 */
-	public static function singleton() {
-		static $singleton;
-
-		if ( $singleton === null ) {
-			$singleton = new static();
-		}
-
-		return $singleton;
-	}
-
-	/**
-	 * @deprecated since 1.21
-	 * @param string $group
-	 * @return SiteList
-	 */
-	public function getSiteGroup( $group ) {
-		return $this->getSites()->getGroup( $group );
-	}
 }
diff --git a/includes/site/SiteStore.php b/includes/site/SiteStore.php
index 537f1ccb..10e0c1b9 100644
--- a/includes/site/SiteStore.php
+++ b/includes/site/SiteStore.php
@@ -26,7 +26,7 @@
  * @license GNU GPL v2+
  * @author Jeroen De Dauw < jeroendedauw@gmail.com >
  */
-interface SiteStore {
+interface SiteStore extends SiteLookup {
 
 	/**
 	 * Saves the provided site.
@@ -51,33 +51,6 @@ interface SiteStore {
 	public function saveSites( array $sites );
 
 	/**
-	 * Returns the site with provided global id, or null if there is no such site.
-	 *
-	 * @since 1.21
-	 *
-	 * @param string $globalId
-	 * @param string $source Either 'cache' or 'recache'.
-	 * If 'cache', the values are allowed (but not obliged) to come from a cache.
-	 *
-	 * @return Site|null
-	 */
-	public function getSite( $globalId, $source = 'cache' );
-
-	/**
-	 * Returns a list of all sites. By default this site is
-	 * fetched from the cache, which can be changed to loading
-	 * the list from the database using the $useCache parameter.
-	 *
-	 * @since 1.21
-	 *
-	 * @param string $source Either 'cache' or 'recache'.
-	 * If 'cache', the values are allowed (but not obliged) to come from a cache.
-	 *
-	 * @return SiteList
-	 */
-	public function getSites( $source = 'cache' );
-
-	/**
 	 * Deletes all sites from the database. After calling clear(), getSites() will return an empty
 	 * list and getSite() will return null until saveSite() or saveSites() is called.
 	 */
diff --git a/includes/site/SitesCacheFileBuilder.php b/includes/site/SitesCacheFileBuilder.php
new file mode 100644
index 00000000..2e420409
--- /dev/null
+++ b/includes/site/SitesCacheFileBuilder.php
@@ -0,0 +1,113 @@
+<?php
+
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @since 1.25
+ *
+ * @file
+ *
+ * @license GNU GPL v2+
+ */
+class SitesCacheFileBuilder {
+
+	/**
+	 * @var SiteLookup
+	 */
+	private $siteLookup;
+
+	/**
+	 * @var string
+	 */
+	private $cacheFile;
+
+	/**
+	 * @param SiteLookup $siteLookup
+	 * @param string $cacheFile
+	 */
+	public function __construct( SiteLookup $siteLookup, $cacheFile ) {
+		$this->siteLookup = $siteLookup;
+		$this->cacheFile = $cacheFile;
+	}
+
+	public function build() {
+		$this->sites = $this->siteLookup->getSites();
+		$this->cacheSites( $this->sites->getArrayCopy() );
+	}
+
+	/**
+	 * @param Site[] $sites
+	 *
+	 * @throws MWException if in manualRecache mode
+	 * @return bool
+	 */
+	private function cacheSites( array $sites ) {
+		$sitesArray = array();
+
+		foreach ( $sites as $site ) {
+			$globalId = $site->getGlobalId();
+			$sitesArray[$globalId] = $this->getSiteAsArray( $site );
+		}
+
+		$json = json_encode( array(
+			'sites' => $sitesArray
+		) );
+
+		$result = file_put_contents( $this->cacheFile, $json );
+
+		return $result !== false;
+	}
+
+	/**
+	 * @param Site $site
+	 *
+	 * @return array
+	 */
+	private function getSiteAsArray( Site $site ) {
+		$siteEntry = unserialize( $site->serialize() );
+		$siteIdentifiers = $this->buildLocalIdentifiers( $site );
+		$identifiersArray = array();
+
+		foreach ( $siteIdentifiers as $identifier ) {
+			$identifiersArray[] = $identifier;
+		}
+
+		$siteEntry['identifiers'] = $identifiersArray;
+
+		return $siteEntry;
+	}
+
+	/**
+	 * @param Site $site
+	 *
+	 * @return array Site local identifiers
+	 */
+	private function buildLocalIdentifiers( Site $site ) {
+		$localIds = array();
+
+		foreach ( $site->getLocalIds() as $idType => $ids ) {
+			foreach ( $ids as $id ) {
+				$localIds[] = array(
+					'type' => $idType,
+					'key' => $id
+				);
+			}
+		}
+
+		return $localIds;
+	}
+
+}