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SvgHandler.php
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SvgHandler.php
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<?php
/**
* Handler for SVG images.
*
* 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 Media
*/
use MediaWiki\Context\IContextSource;
use MediaWiki\Language\LanguageCode;
use MediaWiki\MainConfigNames;
use MediaWiki\MediaWikiServices;
use MediaWiki\Shell\Shell;
use Wikimedia\AtEase\AtEase;
use Wikimedia\ScopedCallback;
/**
* Handler for SVG images.
*
* @ingroup Media
*/
class SvgHandler extends ImageHandler {
public const SVG_METADATA_VERSION = 2;
private const SVG_DEFAULT_RENDER_LANG = 'en';
/** @var array A list of metadata tags that can be converted
* to the commonly used exif tags. This allows messages
* to be reused, and consistent tag names for {{#formatmetadata:..}}
*/
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 ) {
$svgNativeRendering = MediaWikiServices::getInstance()
->getMainConfig()->get( MainConfigNames::SVGNativeRendering );
if ( $svgNativeRendering === true ) {
// Don't do any transform for any SVG.
return true;
}
if ( $svgNativeRendering !== 'partial' ) {
// SVG images are always rasterized to PNG
return false;
}
$maxSVGFilesize = MediaWikiServices::getInstance()
->getMainConfig()->get( MainConfigNames::SVGNativeRenderingSizeLimit );
// Browsers don't really support SVG translations, so always render them to PNG
// Files bigger than the limit are also rendered as PNG, as big files might be a tax on the user agent
return count( $this->getAvailableLanguages( $file ) ) <= 1
&& $file->getSize() <= $maxSVGFilesize;
}
public function mustRender( $file ) {
return !$this->allowRenderingByUserAgent( $file );
}
public function isVectorized( $file ) {
return true;
}
/**
* @param File $file
* @return bool
*/
public function isAnimatedImage( $file ) {
# @todo Detect animated SVGs
$metadata = $this->validateMetadata( $file->getMetadataArray() );
if ( isset( $metadata['animated'] ) ) {
return $metadata['animated'];
}
return false;
}
/**
* Which languages (systemLanguage attribute) is supported.
*
* @note This list is not guaranteed to be exhaustive.
* To avoid OOM errors, we only look at first bit of a file.
* Thus all languages on this list are present in the file,
* but its possible for the file to have a language not on
* this list.
*
* @param File $file
* @return string[] Array of language codes, or empty if no language switching supported.
*/
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 );
}
/**
* SVG's systemLanguage matching rules state:
* 'The `systemLanguage` attribute ... [e]valuates to "true" if one of the languages indicated
* by user preferences exactly equals one of the languages given in the value of this parameter,
* or if one of the languages indicated by user preferences exactly equals a prefix of one of
* the languages given in the value of this parameter such that the first tag character
* following the prefix is "-".'
*
* Return the first element of $svgLanguages that matches $userPreferredLanguage
*
* @see https://www.w3.org/TR/SVG/struct.html#SystemLanguageAttribute
* @param string $userPreferredLanguage
* @param string[] $svgLanguages
* @return string|null
*/
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 ( strpos( $trimmedSvgLang, '-' ) !== false ) {
$trimmedSvgLang = substr( $trimmedSvgLang, 0, strrpos( $trimmedSvgLang, '-' ) );
if ( strcasecmp( $trimmedSvgLang, $userPreferredLanguage ) === 0 ) {
return $svgLang;
}
}
}
return null;
}
/**
* Determines render language from image parameters
* This is a lowercase IETF language
*
* @param array $params
* @return string
*/
protected function getLanguageFromParams( array $params ) {
return $params['lang'] ?? $params['targetlang'] ?? self::SVG_DEFAULT_RENDER_LANG;
}
/**
* What language to render file in if none selected
*
* @param File $file Language code
* @return string
*/
public function getDefaultRenderLanguage( File $file ) {
return self::SVG_DEFAULT_RENDER_LANG;
}
/**
* We do not support making animated svg thumbnails
* @param File $file
* @return bool
*/
public function canAnimateThumbnail( $file ) {
return $this->allowRenderingByUserAgent( $file );
}
/**
* @param File $image
* @param array &$params
* @return bool
*/
public function normaliseParams( $image, &$params ) {
if ( parent::normaliseParams( $image, $params ) ) {
$params = $this->normaliseParamsInternal( $image, $params );
return true;
}
return false;
}
/**
* Code taken out of normaliseParams() for testability
*
* @since 1.33
*
* @param File $image
* @param array $params
* @return array Modified $params
*/
protected function normaliseParamsInternal( $image, $params ) {
$svgMaxSize = MediaWikiServices::getInstance()->getMainConfig()->get( MainConfigNames::SVGMaxSize );
# Don't make an image bigger than wgMaxSVGSize on the smaller side
if ( $params['physicalWidth'] <= $params['physicalHeight'] ) {
if ( $params['physicalWidth'] > $svgMaxSize ) {
$srcWidth = $image->getWidth( $params['page'] );
$srcHeight = $image->getHeight( $params['page'] );
$params['physicalWidth'] = $svgMaxSize;
$params['physicalHeight'] = File::scaleHeight( $srcWidth, $srcHeight, $svgMaxSize );
}
} elseif ( $params['physicalHeight'] > $svgMaxSize ) {
$srcWidth = $image->getWidth( $params['page'] );
$srcHeight = $image->getHeight( $params['page'] );
$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;
}
/**
* @param File $image
* @param string $dstPath
* @param string $dstUrl
* @param array $params
* @param int $flags
* @return MediaTransformError|ThumbnailImage|TransformParameterError|false
*/
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 ) ) {
// No transformation required for native rendering
return new ThumbnailImage( $image, $image->getURL(), false, $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 );
/** @noinspection PhpUnusedLocalVariableInspection */
$cleaner = new ScopedCallback( static function () use ( $tmpDir, $lnPath ) {
AtEase::suppressWarnings();
unlink( $lnPath );
rmdir( $tmpDir );
AtEase::restoreWarnings();
} );
if ( !$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
}
/**
* Transform an SVG file to PNG
* This function can be called outside of thumbnail contexts
* @param string $srcPath
* @param string $dstPath
* @param int $width
* @param int $height
* @param string|false $lang Language code of the language to render the SVG in
* @return bool|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 = false;
$retval = '';
if ( isset( $svgConverters[$svgConverter] ) ) {
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" );
}
$err = $func( $srcPath,
$dstPath,
$width,
$height,
$lang,
...array_slice( $svgConverters[$svgConverter], 1 )
);
$retval = (bool)$err;
} 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 = wfShellExecWithStderr( $cmd, $retval, $env );
}
}
$removed = $this->removeBadFile( $dstPath, $retval );
if ( $retval != 0 || $removed ) {
// @phan-suppress-next-next-line PhanPossiblyUndeclaredVariable cmd is set when used
// @phan-suppress-next-line PhanTypeMismatchArgumentNullable cmd is set when used
$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";
}
}
public function getThumbType( $ext, $mime, $params = null ) {
return [ 'png', 'image/png' ];
}
/**
* Subtitle for the image. Different from the base
* class so it can be denoted that SVG's have
* a "nominal" resolution, and not a fixed one,
* as well as so animation can be denoted.
*
* @param File $file
* @return string
*/
public function getLongDesc( $file ) {
$metadata = $this->validateMetadata( $file->getMetadataArray() );
if ( isset( $metadata['error'] ) ) {
return wfMessage( 'svg-long-error', $metadata['error']['message'] )->text();
}
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() )->parse();
}
/**
* @param MediaHandlerState $state
* @param string $filename
* @return array
*/
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' ];
}
/**
* @param File $file
* @param IContextSource|false $context
* @return array[]|false
*/
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;
}
/**
* @param string $name Parameter name
* @param mixed $value Parameter value
* @return bool Validity
*/
public function validateParam( $name, $value ) {
if ( in_array( $name, [ 'width', 'height' ] ) ) {
// Reject negative heights, widths
return ( $value > 0 );
}
if ( $name === 'lang' ) {
// Validate $code
if ( $value === ''
|| !LanguageCode::isWellFormedLanguageTag( $value )
) {
return false;
}
return true;
}
// Only lang, width and height are acceptable keys
return false;
}
/**
* @param array $params Name=>value pairs of parameters
* @return string|false Filename to use
*/
public function makeParamString( $params ) {
$lang = '';
$code = $this->getLanguageFromParams( $params );
if ( $code !== self::SVG_DEFAULT_RENDER_LANG ) {
$lang = 'lang' . strtolower( $code ) . '-';
}
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' ];
}
/**
* @param array $params
* @return array
*/
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;
}
}

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SvgHandler.php (19 KB)

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