SvgHandler.php

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<?php
namespace MediaWiki\Media;
 
use Imagick;
use MediaWiki\Context\IContextSource;
use MediaWiki\FileRepo\File\File;
use MediaWiki\Language\LanguageCode;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Shell\Shell;
use UnexpectedValueException;
use Wikimedia\ScopedCallback;
 
class SvgHandler extends ImageHandler {
    public const SVG_METADATA_VERSION = 2;
 
    private const SVG_DEFAULT_RENDER_LANG = 'en';
 
    private static $metaConversion = [
        'originalwidth' => 'ImageWidth',
        'originalheight' => 'ImageLength',
        'description' => 'ImageDescription',
        'title' => 'ObjectName',
    ];
 
    public function isEnabled() {
        $config = MediaWikiServices::getInstance()->getMainConfig();
        $svgConverters = $config->get( MainConfigNames::SVGConverters );
        $svgConverter = $config->get( MainConfigNames::SVGConverter );
        if ( $config->get( MainConfigNames::SVGNativeRendering ) === true ) {
            return true;
        }
        if ( !isset( $svgConverters[$svgConverter] ) ) {
            wfDebug( "\$wgSVGConverter is invalid, disabling SVG rendering." );
 
            return false;
        }
 
        return true;
    }
 
    public function allowRenderingByUserAgent( File $file ): bool {
        $svgNativeRendering = MediaWikiServices::getInstance()
            ->getMainConfig()->get( MainConfigNames::SVGNativeRendering );
        if ( $svgNativeRendering === false ) {
            // SVG images are always rasterized to PNG
            return false;
        }
 
        // Files bigger than the limit have to be rendered as PNG, as big files might be a tax on the user agent
        $maxSVGFilesize = MediaWikiServices::getInstance()
            ->getMainConfig()->get( MainConfigNames::SVGNativeRenderingSizeLimit );
        if ( $maxSVGFilesize && $file->getSize() >= $maxSVGFilesize ) {
            return false;
        }
 
        if ( $svgNativeRendering === true ) {
            return true;
        }
 
        // 'partial' mode: only allow if considered safe
        // Browsers don't really support SVG translations, so always render those to PNG
        if ( $svgNativeRendering === 'partial' ) {
            return count( $this->getAvailableLanguages( $file ) ) <= 1;
        }
        return false;
    }
 
    public function mustRender( $file ) {
        return !$this->allowRenderingByUserAgent( $file );
    }
 
    public function isVectorized( $file ) {
        return true;
    }
 
    public function isAnimatedImage( $file ) {
        # @todo Detect animated SVGs
        $metadata = $this->validateMetadata( $file->getMetadataArray() );
        if ( isset( $metadata['animated'] ) ) {
            return $metadata['animated'];
        }
 
        return false;
    }
 
    public function getAvailableLanguages( File $file ) {
        $langList = [];
        $metadata = $this->validateMetadata( $file->getMetadataArray() );
        if ( isset( $metadata['translations'] ) ) {
            foreach ( $metadata['translations'] as $lang => $langType ) {
                if ( $langType === SVGReader::LANG_FULL_MATCH ) {
                    $langList[] = strtolower( $lang );
                }
            }
        }
        return array_unique( $langList );
    }
 
    public function getMatchedLanguage( $userPreferredLanguage, array $svgLanguages ) {
        // Explicitly requested undetermined language (text without svg systemLanguage attribute)
        if ( $userPreferredLanguage === 'und' ) {
            return 'und';
        }
        foreach ( $svgLanguages as $svgLang ) {
            if ( strcasecmp( $svgLang, $userPreferredLanguage ) === 0 ) {
                return $svgLang;
            }
            $trimmedSvgLang = $svgLang;
            while ( str_contains( $trimmedSvgLang, '-' ) ) {
                $trimmedSvgLang = substr( $trimmedSvgLang, 0, strrpos( $trimmedSvgLang, '-' ) );
                if ( strcasecmp( $trimmedSvgLang, $userPreferredLanguage ) === 0 ) {
                    return $svgLang;
                }
            }
        }
        return null;
    }
 
    protected function getLanguageFromParams( array $params ) {
        return $params['lang'] ?? $params['targetlang'] ?? self::SVG_DEFAULT_RENDER_LANG;
    }
 
    public function getDefaultRenderLanguage( File $file ) {
        return self::SVG_DEFAULT_RENDER_LANG;
    }
 
    public function canAnimateThumbnail( $file ) {
        return $this->allowRenderingByUserAgent( $file );
    }
 
    public function normaliseParams( $image, &$params ) {
        if ( parent::normaliseParams( $image, $params ) ) {
            $params = $this->normaliseParamsInternal( $image, $params );
            return true;
        }
 
        return false;
    }
 
    protected function normaliseParamsInternal( $image, $params ) {
        $svgMaxSize = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::SVGMaxSize );
 
        $srcWidth = $image->getWidth( $params['page'] );
        $srcHeight = $image->getHeight( $params['page'] );
        $params['physicalWidth'] = $this->getSteppedThumbWidth(
            $image, $params['physicalWidth'], $srcWidth, $srcHeight
        );
        $params['physicalHeight'] = File::scaleHeight( $srcWidth, $srcHeight, $params['physicalWidth'] );
 
        # Don't make an image bigger than wgMaxSVGSize on the smaller side
        if ( $params['physicalWidth'] <= $params['physicalHeight'] ) {
            if ( $params['physicalWidth'] > $svgMaxSize ) {
                $params['physicalWidth'] = $svgMaxSize;
                $params['physicalHeight'] = File::scaleHeight( $srcWidth, $srcHeight, $svgMaxSize );
            }
        } elseif ( $params['physicalHeight'] > $svgMaxSize ) {
            $params['physicalWidth'] = File::scaleHeight( $srcHeight, $srcWidth, $svgMaxSize );
            $params['physicalHeight'] = $svgMaxSize;
        }
        // To prevent the proliferation of thumbnails in languages not present in SVGs, unless
        // explicitly forced by user.
        if ( isset( $params['targetlang'] ) && !$image->getMatchedLanguage( $params['targetlang'] ) ) {
            unset( $params['targetlang'] );
        }
 
        return $params;
    }
 
    public function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
        if ( !$this->normaliseParams( $image, $params ) ) {
            return new TransformParameterError( $params );
        }
        $clientWidth = $params['width'];
        $clientHeight = $params['height'];
        $physicalWidth = $params['physicalWidth'];
        $physicalHeight = $params['physicalHeight'];
        $lang = $this->getLanguageFromParams( $params );
 
        if ( $this->allowRenderingByUserAgent( $image ) ) {
            return $this->getClientScalingThumbnailImage( $image, $params );
        }
 
        if ( $flags & self::TRANSFORM_LATER ) {
            return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
        }
 
        $metadata = $this->validateMetadata( $image->getMetadataArray() );
        if ( isset( $metadata['error'] ) ) {
            $err = wfMessage( 'svg-long-error', $metadata['error']['message'] );
 
            return new MediaTransformError( 'thumbnail_error', $clientWidth, $clientHeight, $err );
        }
 
        if ( !wfMkdirParents( dirname( $dstPath ), null, __METHOD__ ) ) {
            return new MediaTransformError( 'thumbnail_error', $clientWidth, $clientHeight,
                wfMessage( 'thumbnail_dest_directory' ) );
        }
 
        $srcPath = $image->getLocalRefPath();
        if ( $srcPath === false ) { // Failed to get local copy
            wfDebugLog( 'thumbnail',
                sprintf( 'Thumbnail failed on %s: could not get local copy of "%s"',
                    wfHostname(), $image->getName() ) );
 
            return new MediaTransformError( 'thumbnail_error',
                $params['width'], $params['height'],
                wfMessage( 'filemissing' )
            );
        }
 
        // Make a temp dir with a symlink to the local copy in it.
        // This plays well with rsvg-convert policy for external entities.
        // https://git.gnome.org/browse/librsvg/commit/?id=f01aded72c38f0e18bc7ff67dee800e380251c8e
        $tmpDir = wfTempDir() . '/svg_' . wfRandomString( 24 );
        $lnPath = "$tmpDir/" . basename( $srcPath );
        $ok = mkdir( $tmpDir, 0771 );
        if ( !$ok ) {
            wfDebugLog( 'thumbnail',
                sprintf( 'Thumbnail failed on %s: could not create temporary directory %s',
                    wfHostname(), $tmpDir ) );
            return new MediaTransformError( 'thumbnail_error',
                $params['width'], $params['height'],
                wfMessage( 'thumbnail-temp-create' )->text()
            );
        }
        // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
        $ok = @symlink( $srcPath, $lnPath );
        $cleaner = new ScopedCallback( static function () use ( $tmpDir, $lnPath ) {
            // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
            @unlink( $lnPath );
            // phpcs:ignore Generic.PHP.NoSilencedErrors.Discouraged
            @rmdir( $tmpDir );
        } );
        if ( !$ok ) {
            // Fallback because symlink often fails on Windows
            $ok = copy( $srcPath, $lnPath );
        }
        if ( !$ok ) {
            wfDebugLog( 'thumbnail',
                sprintf( 'Thumbnail failed on %s: could not link %s to %s',
                    wfHostname(), $lnPath, $srcPath ) );
            return new MediaTransformError( 'thumbnail_error',
                $params['width'], $params['height'],
                wfMessage( 'thumbnail-temp-create' )
            );
        }
 
        $status = $this->rasterize( $lnPath, $dstPath, $physicalWidth, $physicalHeight, $lang );
        if ( $status === true ) {
            return new ThumbnailImage( $image, $dstUrl, $dstPath, $params );
        }
 
        return $status; // MediaTransformError
    }
 
    public function rasterize( $srcPath, $dstPath, $width, $height, $lang = false ) {
        $mainConfig = MediaWikiServices::getInstance()->getMainConfig();
        $svgConverters = $mainConfig->get( MainConfigNames::SVGConverters );
        $svgConverter = $mainConfig->get( MainConfigNames::SVGConverter );
        $svgConverterPath = $mainConfig->get( MainConfigNames::SVGConverterPath );
        $err = '';
        $retval = null;
        $cmd = '';
        if ( isset( $svgConverters[$svgConverter] ) ) {
            // Handling largely for imagick PHP extension support (T16706) - ::rasterizeImagickExt()
            if ( is_array( $svgConverters[$svgConverter] ) ) {
                // This is a PHP callable
                $func = $svgConverters[$svgConverter][0];
                if ( !is_callable( $func ) ) {
                    throw new UnexpectedValueException( "$func is not callable" );
                }
                // Returns string on error else void
                $err = $func( $srcPath,
                    $dstPath,
                    $width,
                    $height,
                    $lang,
                    ...array_slice( $svgConverters[$svgConverter], 1 )
                );
                $retval = is_string( $err ) ? 1 : 0;
                $err = is_string( $err ) ? $err : '';
                $cmd = 'PHP Callback: ' . (string)$func;
            } else {
                // External command
                $cmd = strtr( $svgConverters[$svgConverter], [
                    '$path/' => $svgConverterPath ? Shell::escape( "$svgConverterPath/" ) : '',
                    '$width' => (int)$width,
                    '$height' => (int)$height,
                    '$input' => Shell::escape( $srcPath ),
                    '$output' => Shell::escape( $dstPath ),
                ] );
 
                $env = [];
                if ( $lang !== false ) {
                    $env['LANG'] = $lang;
                }
 
                wfDebug( __METHOD__ . ": $cmd" );
                $err = Shell::command()->unsafeCommand( $cmd )->environment( $env )->execute();
                $retval = $err->getExitCode();
                $err = $err->getStderr();
                $err = $err === null ? '' : $err;
            }
        }
        $removed = $this->removeBadFile( $dstPath, (int)$retval );
        if ( ( $retval != 0 || $removed ) && $retval !== null ) {
            $this->logErrorForExternalProcess( $retval, $err, $cmd );
            return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
        }
 
        return true;
    }
 
    public static function rasterizeImagickExt( $srcPath, $dstPath, $width, $height ) {
        $im = new Imagick( $srcPath );
        $im->setBackgroundColor( 'transparent' );
        $im->readImage( $srcPath );
        $im->setImageFormat( 'png' );
        $im->setImageDepth( 8 );
 
        if ( !$im->thumbnailImage( (int)$width, (int)$height, /* fit */ false ) ) {
            return 'Could not resize image';
        }
        if ( !$im->writeImage( $dstPath ) ) {
            return "Could not write to $dstPath";
        }
    }
 
    protected function getClientScalingThumbnailImage( $image, $params ) {
        $url = $image->modifyClientThumbUrl( $image->getUrl(), $params );
        return new ThumbnailImage( $image, $url, null, $params );
    }
 
    public function getThumbType( $ext, $mime, $params = null ) {
        return [ 'png', 'image/png' ];
    }
 
    public function getLongDesc( $file ) {
        $metadata = $this->validateMetadata( $file->getMetadataArray() );
        if ( isset( $metadata['error'] ) ) {
            return wfMessage( 'svg-long-error', $metadata['error']['message'] )
                ->inLanguage( $this->getLanguage() )->escaped();
        }
 
        if ( $this->isAnimatedImage( $file ) ) {
            $msg = wfMessage( 'svg-long-desc-animated' );
        } else {
            $msg = wfMessage( 'svg-long-desc' );
        }
 
        return $msg
            ->numParams( $file->getWidth(), $file->getHeight() )
            ->sizeParams( $file->getSize() )
            ->inLanguage( $this->getLanguage() )
            ->parse();
    }
 
    public function getSizeAndMetadata( $state, $filename ) {
        $metadata = [ 'version' => self::SVG_METADATA_VERSION ];
 
        try {
            $svgReader = new SVGReader( $filename );
            $metadata += $svgReader->getMetadata();
        } catch ( InvalidSVGException $e ) {
            // File not found, broken, etc.
            $metadata['error'] = [
                'message' => $e->getMessage(),
                'code' => $e->getCode()
            ];
            wfDebug( __METHOD__ . ': ' . $e->getMessage() );
        }
 
        return [
            'width' => $metadata['width'] ?? 0,
            'height' => $metadata['height'] ?? 0,
            'metadata' => $metadata
        ];
    }
 
    protected function validateMetadata( $unser ) {
        if ( isset( $unser['version'] ) && $unser['version'] === self::SVG_METADATA_VERSION ) {
            return $unser;
        }
 
        return null;
    }
 
    public function getMetadataType( $image ) {
        return 'parsed-svg';
    }
 
    public function isFileMetadataValid( $image ) {
        $meta = $this->validateMetadata( $image->getMetadataArray() );
        if ( !$meta ) {
            return self::METADATA_BAD;
        }
        if ( !isset( $meta['originalWidth'] ) ) {
            // Old but compatible
            return self::METADATA_COMPATIBLE;
        }
 
        return self::METADATA_GOOD;
    }
 
    protected function visibleMetadataFields() {
        return [ 'objectname', 'imagedescription' ];
    }
 
    public function formatMetadata( $file, $context = false ) {
        $result = [
            'visible' => [],
            'collapsed' => []
        ];
        $metadata = $this->validateMetadata( $file->getMetadataArray() );
        if ( !$metadata || isset( $metadata['error'] ) ) {
            return false;
        }
 
        /* @todo Add a formatter
        $format = new FormatSVG( $metadata );
        $formatted = $format->getFormattedData();
        */
 
        // Sort fields into visible and collapsed
        $visibleFields = $this->visibleMetadataFields();
 
        $showMeta = false;
        foreach ( $metadata as $name => $value ) {
            $tag = strtolower( $name );
            if ( isset( self::$metaConversion[$tag] ) ) {
                $tag = strtolower( self::$metaConversion[$tag] );
            } else {
                // Do not output other metadata not in list
                continue;
            }
            $showMeta = true;
            self::addMeta( $result,
                in_array( $tag, $visibleFields ) ? 'visible' : 'collapsed',
                'exif',
                $tag,
                $value
            );
        }
 
        return $showMeta ? $result : false;
    }
 
    public function validateParam( $name, $value ) {
        if ( in_array( $name, [ 'width', 'height' ] ) ) {
            // Reject negative heights, widths
            return (int)$value > 0;
        }
        if ( $name === 'lang' ) {
            // Validate $code
            if ( !is_string( $value ) || $value === ''
                || !LanguageCode::isWellFormedLanguageTag( $value )
            ) {
                return false;
            }
 
            return true;
        }
 
        // Only lang, width and height are acceptable keys
        return false;
    }
 
    public function makeParamString( $params ) {
        $lang = '';
        $code = $this->getLanguageFromParams( $params );
        if ( $code !== self::SVG_DEFAULT_RENDER_LANG ) {
            $lang = 'lang' . strtolower( $code ) . '-';
        }
 
        if ( isset( $params['physicalWidth'] ) && $params['physicalWidth'] ) {
            return "$lang{$params['physicalWidth']}px";
        }
 
        if ( !isset( $params['width'] ) ) {
            return false;
        }
 
        return "$lang{$params['width']}px";
    }
 
    public function parseParamString( $str ) {
        $m = false;
        // Language codes are supposed to be lowercase
        if ( preg_match( '/^lang([a-z]+(?:-[a-z]+)*)-(\d+)px$/', $str, $m ) ) {
            if ( LanguageCode::isWellFormedLanguageTag( $m[1] ) ) {
                return [ 'width' => array_pop( $m ), 'lang' => $m[1] ];
            }
            return [ 'width' => array_pop( $m ), 'lang' => self::SVG_DEFAULT_RENDER_LANG ];
        }
        if ( preg_match( '/^(\d+)px$/', $str, $m ) ) {
            return [ 'width' => $m[1], 'lang' => self::SVG_DEFAULT_RENDER_LANG ];
        }
        return false;
    }
 
    public function getParamMap() {
        return [ 'img_lang' => 'lang', 'img_width' => 'width' ];
    }
 
    protected function getScriptParams( $params ) {
        $scriptParams = [ 'width' => $params['width'] ];
        if ( isset( $params['lang'] ) ) {
            $scriptParams['lang'] = $params['lang'];
        }
 
        return $scriptParams;
    }
 
    public function getCommonMetaArray( File $file ) {
        $metadata = $this->validateMetadata( $file->getMetadataArray() );
        if ( !$metadata || isset( $metadata['error'] ) ) {
            return [];
        }
        $stdMetadata = [];
        foreach ( $metadata as $name => $value ) {
            $tag = strtolower( $name );
            if ( $tag === 'originalwidth' || $tag === 'originalheight' ) {
                // Skip these. In the exif metadata stuff, it is assumed these
                // are measured in px, which is not the case here.
                continue;
            }
            if ( isset( self::$metaConversion[$tag] ) ) {
                $tag = self::$metaConversion[$tag];
                $stdMetadata[$tag] = $value;
            }
        }
 
        return $stdMetadata;
    }
}
 
class_alias( SvgHandler::class, 'SvgHandler' );