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[mediawiki.git] / includes / filerepo / ForeignAPIRepo.php

<?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
 */

/**
 * A foreign repository with a remote MediaWiki with an API thingy
 *
 * Example config:
 *
 * $wgForeignFileRepos[] = array(
 *   'class'                  => 'ForeignAPIRepo',
 *   'name'                   => 'shared',
 *   'apibase'                => 'http://en.wikipedia.org/w/api.php',
 *   'fetchDescription'       => true, // Optional
 *   'descriptionCacheExpiry' => 3600,
 * );
 *
 * @ingroup FileRepo
 */
class ForeignAPIRepo extends FileRepo {
        /* 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 = array(
                'url',
                'thumbnail',
                'timestamp',
        );

        protected $fileFactory = array( 'ForeignAPIFile', 'newFromTitle' );
        /** @var int Check back with Commons after a day (24*60*60) */
        protected $apiThumbCacheExpiry = 86400;

        /** @var int Redownload thumbnail files after a month (86400*30) */
        protected $fileCacheExpiry = 2592000;

        /** @var array */
        protected $mFileExists = array();

        /** @var array */
        private $mQueryCache = array();

        /**
         * @param array|null $info
         */
        function __construct( $info ) {
                global $wgLocalFileRepo;
                parent::__construct( $info );

                // http://commons.wikimedia.org/w/api.php
                $this->mApiBase = isset( $info['apibase'] ) ? $info['apibase'] : null;

                if ( isset( $info['apiThumbCacheExpiry'] ) ) {
                        $this->apiThumbCacheExpiry = $info['apiThumbCacheExpiry'];
                }
                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 ) {
                        $this->url = $wgLocalFileRepo['url'];
                }
                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
         */
        function newFile( $title, $time = false ) {
                if ( $time ) {
                        return false;
                }

                return parent::newFile( $title, $time );
        }

        /**
         * @param array $files
         * @return array
         */
        function fileExistsBatch( array $files ) {
                $results = array();
                foreach ( $files as $k => $f ) {
                        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
                                # 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'." );
                        }
                }

                $data = $this->fetchImageQuery( array(
                        '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;
        }

        /**
         * @param array $query
         * @return string
         */
        function fetchImageQuery( $query ) {
                global $wgLanguageCode;

                $query = array_merge( $query,
                        array(
                                'format' => 'json',
                                'action' => 'query',
                                'redirects' => 'true'
                        ) );

                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;
                }
        }

        /**
         * @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];
                                }
                        }
                }

                return false;
        }

        /**
         * @param string $hash
         * @return array
         */
        function findBySha1( $hash ) {
                $results = $this->fetchImageQuery( array(
                        'aisha1base36' => $hash,
                        'aiprop' => ForeignAPIFile::getProps(),
                        'list' => 'allimages',
                ) );
                $ret = array();
                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;
        }

        /**
         * @param string $name
         * @param int $width
         * @param int $height
         * @param array $result Out parameter that will be changed by the function.
         * @param string $otherParams
         *
         * @return bool
         */
        function getThumbUrl( $name, $width = -1, $height = -1, &$result = null, $otherParams = '' ) {
                $data = $this->fetchImageQuery( array(
                        'titles' => 'File:' . $name,
                        'iiprop' => self::getIIProps(),
                        'iiurlwidth' => $width,
                        'iiurlheight' => $height,
                        '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;
                }
        }

        /**
         * @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( array(
                        'titles' => 'File:' . $name,
                        'iiprop' => self::getIIProps(),
                        'iiurlwidth' => $width,
                        'iiurlheight' => $height,
                        'iiurlparam' => $otherParams,
                        'prop' => 'imageinfo',
                        'uselang' => $lang,
                ) );
                $info = $this->getImageInfo( $data );

                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 = "" ) {
                global $wgMemc;
                // 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 );
                $sizekey = "$width:$height:$params";

                /* Get the array of urls that we already know */
                $knownThumbUrls = $wgMemc->get( $key );
                if ( !$knownThumbUrls ) {
                        /* No knownThumbUrls for this file */
                        $knownThumbUrls = array();
                } else {
                        if ( isset( $knownThumbUrls[$sizekey] ) ) {
                                wfDebug( __METHOD__ . ': Got thumburl from local cache: ' .
                                        "{$knownThumbUrls[$sizekey]} \n" );

                                return $knownThumbUrls[$sizekey];
                        }
                        /* 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( array( 'src' => $localFilename ) )
                        && isset( $metadata['timestamp'] )
                ) {
                        wfDebug( __METHOD__ . " Thumbnail was already downloaded before\n" );
                        $modified = $backend->getFileTimestamp( array( '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;
                                $wgMemc->set( $key, $knownThumbUrls, $this->apiThumbCacheExpiry );

                                return $localUrl;
                        }
                        /* There is a new Commons file, or existing thumbnail older than a month */
                }
                $thumb = self::httpGet( $foreignUrl );
                if ( !$thumb ) {
                        wfDebug( __METHOD__ . " Could not download thumb\n" );

                        return false;
                }

                # @todo FIXME: Delete old thumbs that aren't being used. Maintenance script?
                $backend->prepare( array( 'dir' => dirname( $localFilename ) ) );
                $params = array( 'dst' => $localFilename, 'content' => $thumb );
                if ( !$backend->quickCreate( $params )->isOK() ) {
                        wfDebug( __METHOD__ . " could not write to thumb path '$localFilename'\n" );

                        return $foreignUrl;
                }
                $knownThumbUrls[$sizekey] = $localUrl;
                $wgMemc->set( $key, $knownThumbUrls, $this->apiThumbCacheExpiry );
                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, $ext = null ) {
                switch ( $zone ) {
                        case 'public':
                                return $this->url;
                        case 'thumb':
                                return $this->thumbUrl;
                        default:
                                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 = array( 'public', 'thumb' );
                if ( in_array( $zone, $supported ) ) {
                        return parent::getZonePath( $zone );
                }

                return false;
        }

        /**
         * Are we locally caching the thumbnails?
         * @return bool
         */
        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 = array(
                        '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
         * @return bool|string
         */
        public static function httpGet( $url, $timeout = 'default', $options = array() ) {
                $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( ForeignAPIRepo::getUserAgent() );
                $status = $req->execute();

                if ( $status->isOK() ) {
                        return $req->getContent();
                } else {
                        return false;
                }
        }

        /**
         * @return string
         * @since 1.23
         */
        protected static function getIIProps() {
                return join( '|', 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 null
         */
        public function httpGetCached( $target, $query, $cacheTTL = 3600 ) {
                if ( $this->mApiBase ) {
                        $url = wfAppendQuery( $this->mApiBase, $query );
                } else {
                        $url = $this->makeUrl( $query, 'api' );
                }

                if ( !isset( $this->mQueryCache[$url] ) ) {
                        global $wgMemc;

                        $key = $this->getLocalCacheKey( get_class( $this ), $target, md5( $url ) );
                        $data = $wgMemc->get( $key );

                        if ( !$data ) {
                                $data = self::httpGet( $url );

                                if ( !$data ) {
                                        return null;
                                }

                                $wgMemc->set( $key, $data, $cacheTTL );
                        }

                        if ( count( $this->mQueryCache ) > 100 ) {
                                // Keep the cache from growing infinitely
                                $this->mQueryCache = array();
                        }

                        $this->mQueryCache[$url] = $data;
                }

                return $this->mQueryCache[$url];
        }

        /**
         * @param callable $callback
         * @throws MWException
         */
        function enumFiles( $callback ) {
                throw new MWException( 'enumFiles is not supported by ' . get_class( $this ) );
        }

        /**
         * @throws MWException
         */
        protected function assertWritableRepo() {
                throw new MWException( get_class( $this ) . ': write operations are not supported.' );
        }
}