<?php
+/**
+ * Foreign repository accessible through api.php requests.
+ *
+ * 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
+ * @ingroup FileRepo
+ */
+
+use MediaWiki\Logger\LoggerFactory;
/**
* A foreign repository with a remote MediaWiki with an API thingy
- * Very hacky and inefficient
- * do not use except for testing :D
*
* Example config:
*
- * $wgForeignFileRepos[] = array(
+ * $wgForeignFileRepos[] = [
* 'class' => 'ForeignAPIRepo',
* 'name' => 'shared',
- * 'apibase' => 'http://en.wikipedia.org/w/api.php',
+ * 'apibase' => 'https://en.wikipedia.org/w/api.php',
* 'fetchDescription' => true, // Optional
* 'descriptionCacheExpiry' => 3600,
- * );
+ * ];
*
* @ingroup FileRepo
*/
class ForeignAPIRepo extends FileRepo {
- var $fileFactory = array( 'ForeignAPIFile', 'newFromTitle' );
- var $apiThumbCacheExpiry = 86400;
- protected $mQueryCache = array();
- protected $mFileExists = array();
+ /* This version string is used in the user agent for requests and will help
+ * server maintainers in identify ForeignAPI usage.
+ * Update the version every time you make breaking or significant changes. */
+ const VERSION = "2.1";
+
+ /**
+ * List of iiprop values for the thumbnail fetch queries.
+ * @since 1.23
+ */
+ protected static $imageInfoProps = [
+ 'url',
+ 'timestamp',
+ ];
+ protected $fileFactory = [ 'ForeignAPIFile', 'newFromTitle' ];
+ /** @var int Check back with Commons after this expiry */
+ protected $apiThumbCacheExpiry = 86400; // 1 day (24*3600)
+
+ /** @var int Redownload thumbnail files after this expiry */
+ protected $fileCacheExpiry = 2592000; // 1 month (30*24*3600)
+
+ /** @var array */
+ protected $mFileExists = [];
+
+ /** @var string */
+ private $mApiBase;
+
+ /**
+ * @param array|null $info
+ */
function __construct( $info ) {
+ global $wgLocalFileRepo;
parent::__construct( $info );
- $this->mApiBase = $info['apibase']; // http://commons.wikimedia.org/w/api.php
- if( isset( $info['apiThumbCacheExpiry'] ) ) {
+
+ // https://commons.wikimedia.org/w/api.php
+ $this->mApiBase = isset( $info['apibase'] ) ? $info['apibase'] : null;
+
+ if ( isset( $info['apiThumbCacheExpiry'] ) ) {
$this->apiThumbCacheExpiry = $info['apiThumbCacheExpiry'];
}
- if( !$this->scriptDirUrl ) {
+ if ( isset( $info['fileCacheExpiry'] ) ) {
+ $this->fileCacheExpiry = $info['fileCacheExpiry'];
+ }
+ if ( !$this->scriptDirUrl ) {
// hack for description fetches
$this->scriptDirUrl = dirname( $this->mApiBase );
}
// If we can cache thumbs we can guess sane defaults for these
- if( $this->canCacheThumbs() && !$this->url ) {
- global $wgLocalFileRepo;
+ if ( $this->canCacheThumbs() && !$this->url ) {
$this->url = $wgLocalFileRepo['url'];
}
- if( $this->canCacheThumbs() && !$this->thumbUrl ) {
+ if ( $this->canCacheThumbs() && !$this->thumbUrl ) {
$this->thumbUrl = $this->url . '/thumb';
}
}
+ /**
+ * @return string
+ * @since 1.22
+ */
+ function getApiUrl() {
+ return $this->mApiBase;
+ }
+
/**
* Per docs in FileRepo, this needs to return false if we don't support versioned
* files. Well, we don't.
+ *
+ * @param Title $title
+ * @param string|bool $time
+ * @return File|false
*/
function newFile( $title, $time = false ) {
if ( $time ) {
return false;
}
- return parent::newFile( $title, $time );
- }
-/**
- * No-ops
- */
- function storeBatch( $triplets, $flags = 0 ) {
- return false;
- }
- function storeTemp( $originalName, $srcPath ) {
- return false;
- }
- function append( $srcPath, $toAppendPath, $flags = 0 ){
- return false;
- }
- function publishBatch( $triplets, $flags = 0 ) {
- return false;
- }
- function deleteBatch( $sourceDestPairs ) {
- return false;
+ return parent::newFile( $title, $time );
}
-
- function fileExistsBatch( $files, $flags = 0 ) {
- $results = array();
+ /**
+ * @param array $files
+ * @return array
+ */
+ function fileExistsBatch( array $files ) {
+ $results = [];
foreach ( $files as $k => $f ) {
- if ( isset( $this->mFileExists[$k] ) ) {
- $results[$k] = true;
+ if ( isset( $this->mFileExists[$f] ) ) {
+ $results[$k] = $this->mFileExists[$f];
unset( $files[$k] );
- } elseif( self::isVirtualUrl( $f ) ) {
- # TODO! FIXME! We need to be able to handle virtual
+ } elseif ( self::isVirtualUrl( $f ) ) {
+ # @todo FIXME: We need to be able to handle virtual
# URLs better, at least when we know they refer to the
# same repo.
$results[$k] = false;
unset( $files[$k] );
+ } elseif ( FileBackend::isStoragePath( $f ) ) {
+ $results[$k] = false;
+ unset( $files[$k] );
+ wfWarn( "Got mwstore:// path '$f'." );
}
}
- $results = $this->fetchImageQuery( array( 'titles' => implode( $files, '|' ),
- 'prop' => 'imageinfo' ) );
- if( isset( $data['query']['pages'] ) ) {
- $i = 0;
- foreach( $files as $key => $file ) {
- $results[$key] = $this->mFileExists[$key] = !isset( $data['query']['pages'][$i]['missing'] );
- $i++;
+ $data = $this->fetchImageQuery( [
+ 'titles' => implode( $files, '|' ),
+ 'prop' => 'imageinfo' ]
+ );
+
+ if ( isset( $data['query']['pages'] ) ) {
+ # First, get results from the query. Note we only care whether the image exists,
+ # not whether it has a description page.
+ foreach ( $data['query']['pages'] as $p ) {
+ $this->mFileExists[$p['title']] = ( $p['imagerepository'] !== '' );
+ }
+ # Second, copy the results to any redirects that were queried
+ if ( isset( $data['query']['redirects'] ) ) {
+ foreach ( $data['query']['redirects'] as $r ) {
+ $this->mFileExists[$r['from']] = $this->mFileExists[$r['to']];
+ }
+ }
+ # Third, copy the results to any non-normalized titles that were queried
+ if ( isset( $data['query']['normalized'] ) ) {
+ foreach ( $data['query']['normalized'] as $n ) {
+ $this->mFileExists[$n['from']] = $this->mFileExists[$n['to']];
+ }
+ }
+ # Finally, copy the results to the output
+ foreach ( $files as $key => $file ) {
+ $results[$key] = $this->mFileExists[$file];
}
}
+
+ return $results;
}
+
+ /**
+ * @param string $virtualUrl
+ * @return bool
+ */
function getFileProps( $virtualUrl ) {
return false;
}
- protected function queryImage( $query ) {
- $data = $this->fetchImageQuery( $query );
+ /**
+ * @param array $query
+ * @return string
+ */
+ function fetchImageQuery( $query ) {
+ global $wgLanguageCode;
+
+ $query = array_merge( $query,
+ [
+ 'format' => 'json',
+ 'action' => 'query',
+ 'redirects' => 'true'
+ ] );
- if( isset( $data['query']['pages'] ) ) {
- foreach( $data['query']['pages'] as $pageid => $info ) {
- if( isset( $info['imageinfo'][0] ) ) {
- return $info['imageinfo'][0];
- }
- }
+ if ( !isset( $query['uselang'] ) ) { // uselang is unset or null
+ $query['uselang'] = $wgLanguageCode;
+ }
+
+ $data = $this->httpGetCached( 'Metadata', $query );
+
+ if ( $data ) {
+ return FormatJson::decode( $data, true );
+ } else {
+ return null;
}
- return false;
}
- protected function fetchImageQuery( $query ) {
- global $wgMemc;
-
- $url = $this->mApiBase .
- '?' .
- wfArrayToCgi(
- array_merge( $query,
- array(
- 'format' => 'json',
- 'action' => 'query' ) ) );
-
- if( !isset( $this->mQueryCache[$url] ) ) {
- $key = $this->getLocalCacheKey( 'ForeignAPIRepo', 'Metadata', md5( $url ) );
- $data = $wgMemc->get( $key );
- if( !$data ) {
- $data = Http::get( $url );
- if ( !$data ) {
- return null;
+ /**
+ * @param array $data
+ * @return bool|array
+ */
+ function getImageInfo( $data ) {
+ if ( $data && isset( $data['query']['pages'] ) ) {
+ foreach ( $data['query']['pages'] as $info ) {
+ if ( isset( $info['imageinfo'][0] ) ) {
+ $return = $info['imageinfo'][0];
+ if ( isset( $info['pageid'] ) ) {
+ $return['pageid'] = $info['pageid'];
+ }
+ return $return;
}
- $wgMemc->set( $key, $data, 3600 );
}
-
- if( count( $this->mQueryCache ) > 100 ) {
- // Keep the cache from growing infinitely
- $this->mQueryCache = array();
- }
- $this->mQueryCache[$url] = $data;
}
- return FormatJson::decode( $this->mQueryCache[$url], true );
- }
- function getImageInfo( $title, $time = false ) {
- return $this->queryImage( array(
- 'titles' => 'Image:' . $title->getText(),
- 'iiprop' => 'timestamp|user|comment|url|size|sha1|metadata|mime',
- 'prop' => 'imageinfo' ) );
+ return false;
}
+ /**
+ * @param string $hash
+ * @return array
+ */
function findBySha1( $hash ) {
- $results = $this->fetchImageQuery( array(
- 'aisha1base36' => $hash,
- 'aiprop' => 'timestamp|user|comment|url|size|sha1|metadata|mime',
- 'list' => 'allimages', ) );
- $ret = array();
+ $results = $this->fetchImageQuery( [
+ 'aisha1base36' => $hash,
+ 'aiprop' => ForeignAPIFile::getProps(),
+ 'list' => 'allimages',
+ ] );
+ $ret = [];
if ( isset( $results['query']['allimages'] ) ) {
foreach ( $results['query']['allimages'] as $img ) {
+ // 1.14 was broken, doesn't return name attribute
+ if ( !isset( $img['name'] ) ) {
+ continue;
+ }
$ret[] = new ForeignAPIFile( Title::makeTitle( NS_FILE, $img['name'] ), $this, $img );
}
}
+
return $ret;
}
- function getThumbUrl( $name, $width=-1, $height=-1 ) {
- $info = $this->queryImage( array(
- 'titles' => 'Image:' . $name,
- 'iiprop' => 'url',
+ /**
+ * @param string $name
+ * @param int $width
+ * @param int $height
+ * @param array &$result
+ * @param string $otherParams
+ *
+ * @return bool
+ */
+ function getThumbUrl( $name, $width = -1, $height = -1, &$result = null, $otherParams = '' ) {
+ $data = $this->fetchImageQuery( [
+ 'titles' => 'File:' . $name,
+ 'iiprop' => self::getIIProps(),
'iiurlwidth' => $width,
'iiurlheight' => $height,
- 'prop' => 'imageinfo' ) );
- if( $info && $info['thumburl'] ) {
+ 'iiurlparam' => $otherParams,
+ 'prop' => 'imageinfo' ] );
+ $info = $this->getImageInfo( $data );
+
+ if ( $data && $info && isset( $info['thumburl'] ) ) {
wfDebug( __METHOD__ . " got remote thumb " . $info['thumburl'] . "\n" );
+ $result = $info;
+
return $info['thumburl'];
} else {
return false;
}
}
- function getThumbUrlFromCache( $name, $width, $height ) {
- global $wgMemc, $wgUploadPath, $wgServer, $wgUploadDirectory;
+ /**
+ * @param string $name
+ * @param int $width
+ * @param int $height
+ * @param string $otherParams
+ * @param string $lang Language code for language of error
+ * @return bool|MediaTransformError
+ * @since 1.22
+ */
+ function getThumbError( $name, $width = -1, $height = -1, $otherParams = '', $lang = null ) {
+ $data = $this->fetchImageQuery( [
+ 'titles' => 'File:' . $name,
+ 'iiprop' => self::getIIProps(),
+ 'iiurlwidth' => $width,
+ 'iiurlheight' => $height,
+ 'iiurlparam' => $otherParams,
+ 'prop' => 'imageinfo',
+ 'uselang' => $lang,
+ ] );
+ $info = $this->getImageInfo( $data );
- if ( !$this->canCacheThumbs() ) {
- return $this->getThumbUrl( $name, $width, $height );
+ if ( $data && $info && isset( $info['thumberror'] ) ) {
+ wfDebug( __METHOD__ . " got remote thumb error " . $info['thumberror'] . "\n" );
+
+ return new MediaTransformError(
+ 'thumbnail_error_remote',
+ $width,
+ $height,
+ $this->getDisplayName(),
+ $info['thumberror'] // already parsed message from foreign repo
+ );
+ } else {
+ return false;
}
+ }
+ /**
+ * Return the imageurl from cache if possible
+ *
+ * If the url has been requested today, get it from cache
+ * Otherwise retrieve remote thumb url, check for local file.
+ *
+ * @param string $name Is a dbkey form of a title
+ * @param int $width
+ * @param int $height
+ * @param string $params Other rendering parameters (page number, etc)
+ * from handler's makeParamString.
+ * @return bool|string
+ */
+ function getThumbUrlFromCache( $name, $width, $height, $params = "" ) {
+ $cache = ObjectCache::getMainWANInstance();
+ // We can't check the local cache using FileRepo functions because
+ // we override fileExistsBatch(). We have to use the FileBackend directly.
+ $backend = $this->getBackend(); // convenience
+
+ if ( !$this->canCacheThumbs() ) {
+ $result = null; // can't pass "null" by reference, but it's ok as default value
+ return $this->getThumbUrl( $name, $width, $height, $result, $params );
+ }
$key = $this->getLocalCacheKey( 'ForeignAPIRepo', 'ThumbUrl', $name );
- if ( $thumbUrl = $wgMemc->get($key) ) {
- wfDebug("Got thumb from local cache. $thumbUrl \n");
- return $thumbUrl;
- }
- else {
- $foreignUrl = $this->getThumbUrl( $name, $width, $height );
- if( !$foreignUrl ) {
- wfDebug( __METHOD__ . " Could not find thumburl\n" );
- return false;
- }
- $thumb = Http::get( $foreignUrl );
- if( !$thumb ) {
- wfDebug( __METHOD__ . " Could not download thumb\n" );
- return false;
- }
- // We need the same filename as the remote one :)
- $fileName = rawurldecode( pathinfo( $foreignUrl, PATHINFO_BASENAME ) );
- $path = 'thumb/' . $this->getHashPath( $name ) . $name . "/";
- if ( !is_dir($wgUploadDirectory . '/' . $path) ) {
- wfMkdirParents($wgUploadDirectory . '/' . $path);
+ $sizekey = "$width:$height:$params";
+
+ /* Get the array of urls that we already know */
+ $knownThumbUrls = $cache->get( $key );
+ if ( !$knownThumbUrls ) {
+ /* No knownThumbUrls for this file */
+ $knownThumbUrls = [];
+ } else {
+ if ( isset( $knownThumbUrls[$sizekey] ) ) {
+ wfDebug( __METHOD__ . ': Got thumburl from local cache: ' .
+ "{$knownThumbUrls[$sizekey]} \n" );
+
+ return $knownThumbUrls[$sizekey];
}
- $localUrl = $wgServer . $wgUploadPath . '/' . $path . $fileName;
- # FIXME: Delete old thumbs that aren't being used. Maintenance script?
- if( !file_put_contents($wgUploadDirectory . '/' . $path . $fileName, $thumb ) ) {
- wfDebug( __METHOD__ . " could not write to thumb path\n" );
- return $foreignUrl;
+ /* This size is not yet known */
+ }
+
+ $metadata = null;
+ $foreignUrl = $this->getThumbUrl( $name, $width, $height, $metadata, $params );
+
+ if ( !$foreignUrl ) {
+ wfDebug( __METHOD__ . " Could not find thumburl\n" );
+
+ return false;
+ }
+
+ // We need the same filename as the remote one :)
+ $fileName = rawurldecode( pathinfo( $foreignUrl, PATHINFO_BASENAME ) );
+ if ( !$this->validateFilename( $fileName ) ) {
+ wfDebug( __METHOD__ . " The deduced filename $fileName is not safe\n" );
+
+ return false;
+ }
+ $localPath = $this->getZonePath( 'thumb' ) . "/" . $this->getHashPath( $name ) . $name;
+ $localFilename = $localPath . "/" . $fileName;
+ $localUrl = $this->getZoneUrl( 'thumb' ) . "/" . $this->getHashPath( $name ) .
+ rawurlencode( $name ) . "/" . rawurlencode( $fileName );
+
+ if ( $backend->fileExists( [ 'src' => $localFilename ] )
+ && isset( $metadata['timestamp'] )
+ ) {
+ wfDebug( __METHOD__ . " Thumbnail was already downloaded before\n" );
+ $modified = $backend->getFileTimestamp( [ 'src' => $localFilename ] );
+ $remoteModified = strtotime( $metadata['timestamp'] );
+ $current = time();
+ $diff = abs( $modified - $current );
+ if ( $remoteModified < $modified && $diff < $this->fileCacheExpiry ) {
+ /* Use our current and already downloaded thumbnail */
+ $knownThumbUrls[$sizekey] = $localUrl;
+ $cache->set( $key, $knownThumbUrls, $this->apiThumbCacheExpiry );
+
+ return $localUrl;
}
- $wgMemc->set( $key, $localUrl, $this->apiThumbCacheExpiry );
- wfDebug( __METHOD__ . " got local thumb $localUrl, saving to cache \n" );
- return $localUrl;
+ /* There is a new Commons file, or existing thumbnail older than a month */
}
+
+ $thumb = self::httpGet( $foreignUrl, 'default', [], $mtime );
+ if ( !$thumb ) {
+ wfDebug( __METHOD__ . " Could not download thumb\n" );
+
+ return false;
+ }
+
+ # @todo FIXME: Delete old thumbs that aren't being used. Maintenance script?
+ $backend->prepare( [ 'dir' => dirname( $localFilename ) ] );
+ $params = [ 'dst' => $localFilename, 'content' => $thumb ];
+ if ( !$backend->quickCreate( $params )->isOK() ) {
+ wfDebug( __METHOD__ . " could not write to thumb path '$localFilename'\n" );
+
+ return $foreignUrl;
+ }
+ $knownThumbUrls[$sizekey] = $localUrl;
+
+ $ttl = $mtime
+ ? $cache->adaptiveTTL( $mtime, $this->apiThumbCacheExpiry )
+ : $this->apiThumbCacheExpiry;
+ $cache->set( $key, $knownThumbUrls, $ttl );
+ wfDebug( __METHOD__ . " got local thumb $localUrl, saving to cache \n" );
+
+ return $localUrl;
}
/**
* @see FileRepo::getZoneUrl()
+ * @param string $zone
+ * @param string|null $ext Optional file extension
+ * @return string
*/
- function getZoneUrl( $zone ) {
+ function getZoneUrl( $zone, $ext = null ) {
switch ( $zone ) {
case 'public':
return $this->url;
case 'thumb':
return $this->thumbUrl;
default:
- return parent::getZoneUrl( $zone );
+ return parent::getZoneUrl( $zone, $ext );
+ }
+ }
+
+ /**
+ * Get the local directory corresponding to one of the basic zones
+ * @param string $zone
+ * @return bool|null|string
+ */
+ function getZonePath( $zone ) {
+ $supported = [ 'public', 'thumb' ];
+ if ( in_array( $zone, $supported ) ) {
+ return parent::getZonePath( $zone );
}
+
+ return false;
}
/**
public function canCacheThumbs() {
return ( $this->apiThumbCacheExpiry > 0 );
}
+
+ /**
+ * The user agent the ForeignAPIRepo will use.
+ * @return string
+ */
+ public static function getUserAgent() {
+ return Http::userAgent() . " ForeignAPIRepo/" . self::VERSION;
+ }
+
+ /**
+ * Get information about the repo - overrides/extends the parent
+ * class's information.
+ * @return array
+ * @since 1.22
+ */
+ function getInfo() {
+ $info = parent::getInfo();
+ $info['apiurl'] = $this->getApiUrl();
+
+ $query = [
+ 'format' => 'json',
+ 'action' => 'query',
+ 'meta' => 'siteinfo',
+ 'siprop' => 'general',
+ ];
+
+ $data = $this->httpGetCached( 'SiteInfo', $query, 7200 );
+
+ if ( $data ) {
+ $siteInfo = FormatJson::decode( $data, true );
+ $general = $siteInfo['query']['general'];
+
+ $info['articlepath'] = $general['articlepath'];
+ $info['server'] = $general['server'];
+
+ if ( isset( $general['favicon'] ) ) {
+ $info['favicon'] = $general['favicon'];
+ }
+ }
+
+ return $info;
+ }
+
+ /**
+ * Like a Http:get request, but with custom User-Agent.
+ * @see Http::get
+ * @param string $url
+ * @param string $timeout
+ * @param array $options
+ * @param int|bool &$mtime Resulting Last-Modified UNIX timestamp if received
+ * @return bool|string
+ */
+ public static function httpGet(
+ $url, $timeout = 'default', $options = [], &$mtime = false
+ ) {
+ $options['timeout'] = $timeout;
+ /* Http::get */
+ $url = wfExpandUrl( $url, PROTO_HTTP );
+ wfDebug( "ForeignAPIRepo: HTTP GET: $url\n" );
+ $options['method'] = "GET";
+
+ if ( !isset( $options['timeout'] ) ) {
+ $options['timeout'] = 'default';
+ }
+
+ $req = MWHttpRequest::factory( $url, $options, __METHOD__ );
+ $req->setUserAgent( self::getUserAgent() );
+ $status = $req->execute();
+
+ if ( $status->isOK() ) {
+ $lmod = $req->getResponseHeader( 'Last-Modified' );
+ $mtime = $lmod ? wfTimestamp( TS_UNIX, $lmod ) : false;
+
+ return $req->getContent();
+ } else {
+ $logger = LoggerFactory::getInstance( 'http' );
+ $logger->warning(
+ $status->getWikiText( false, false, 'en' ),
+ [ 'caller' => 'ForeignAPIRepo::httpGet' ]
+ );
+
+ return false;
+ }
+ }
+
+ /**
+ * @return string
+ * @since 1.23
+ */
+ protected static function getIIProps() {
+ return implode( '|', self::$imageInfoProps );
+ }
+
+ /**
+ * HTTP GET request to a mediawiki API (with caching)
+ * @param string $target Used in cache key creation, mostly
+ * @param array $query The query parameters for the API request
+ * @param int $cacheTTL Time to live for the memcached caching
+ * @return string|null
+ */
+ public function httpGetCached( $target, $query, $cacheTTL = 3600 ) {
+ if ( $this->mApiBase ) {
+ $url = wfAppendQuery( $this->mApiBase, $query );
+ } else {
+ $url = $this->makeUrl( $query, 'api' );
+ }
+
+ $cache = ObjectCache::getMainWANInstance();
+ return $cache->getWithSetCallback(
+ $this->getLocalCacheKey( static::class, $target, md5( $url ) ),
+ $cacheTTL,
+ function ( $curValue, &$ttl ) use ( $url, $cache ) {
+ $html = self::httpGet( $url, 'default', [], $mtime );
+ if ( $html !== false ) {
+ $ttl = $mtime ? $cache->adaptiveTTL( $mtime, $ttl ) : $ttl;
+ } else {
+ $ttl = $cache->adaptiveTTL( $mtime, $ttl );
+ $html = null; // caches negatives
+ }
+
+ return $html;
+ },
+ [ 'pcTTL' => $cache::TTL_PROC_LONG ]
+ );
+ }
+
+ /**
+ * @param callable $callback
+ * @throws MWException
+ */
+ function enumFiles( $callback ) {
+ throw new MWException( 'enumFiles is not supported by ' . static::class );
+ }
+
+ /**
+ * @throws MWException
+ */
+ protected function assertWritableRepo() {
+ throw new MWException( static::class . ': write operations are not supported.' );
+ }
}