PdfHandler.php

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<?php
class PdfHandler extends ImageHandler {
    public static $messages = [
        'main' => 'pdf-file-page-warning',
        'header' => 'pdf-file-page-warning-header',
        'info' => 'pdf-file-page-warning-info',
        'footer' => 'pdf-file-page-warning-footer',
    ];
 
    public function isEnabled() {
        global $wgPdfProcessor, $wgPdfPostProcessor, $wgPdfInfo;
 
        if ( !isset( $wgPdfProcessor ) || !isset( $wgPdfPostProcessor ) || !isset( $wgPdfInfo ) ) {
            wfDebug( "PdfHandler is disabled, please set the following\n" );
            wfDebug( "variables in LocalSettings.php:\n" );
            wfDebug( "\$wgPdfProcessor, \$wgPdfPostProcessor, \$wgPdfInfo\n" );
            return false;
        }
        return true;
    }
 
    public function mustRender( $file ) {
        return true;
    }
 
    public function isMultiPage( $file ) {
        return true;
    }
 
    public function validateParam( $name, $value ) {
        if ( $name === 'page' && trim( $value ) !== (string)intval( $value ) ) {
            // Extra junk on the end of page, probably actually a caption
            // e.g. [[File:Foo.pdf|thumb|Page 3 of the document shows foo]]
            return false;
        }
        if ( in_array( $name, [ 'width', 'height', 'page' ] ) ) {
            return ( $value > 0 );
        }
        return false;
    }
 
    public function makeParamString( $params ) {
        $page = $params['page'] ?? 1;
        if ( !isset( $params['width'] ) ) {
            return false;
        }
        return "page{$page}-{$params['width']}px";
    }
 
    public function parseParamString( $str ) {
        $m = [];
 
        if ( preg_match( '/^page(\d+)-(\d+)px$/', $str, $m ) ) {
            return [ 'width' => $m[2], 'page' => $m[1] ];
        }
 
        return false;
    }
 
    public function getScriptParams( $params ) {
        return [
            'width' => $params['width'],
            'page' => $params['page'],
        ];
    }
 
    public function getParamMap() {
        return [
            'img_width' => 'width',
            'img_page' => 'page',
        ];
    }
 
    protected function doThumbError( $width, $height, $msg ) {
        return new MediaTransformError( 'thumbnail_error',
            $width, $height, wfMessage( $msg )->inContentLanguage()->text() );
    }
 
    public function doTransform( $image, $dstPath, $dstUrl, $params, $flags = 0 ) {
        global $wgPdfProcessor, $wgPdfPostProcessor, $wgPdfHandlerDpi, $wgPdfHandlerJpegQuality;
 
        if ( !$this->normaliseParams( $image, $params ) ) {
            return new TransformParameterError( $params );
        }
 
        $width = (int)$params['width'];
        $height = (int)$params['height'];
        $page = (int)$params['page'];
 
        if ( $page > $this->pageCount( $image ) ) {
            return $this->doThumbError( $width, $height, 'pdf_page_error' );
        }
 
        if ( $flags & self::TRANSFORM_LATER ) {
            return new ThumbnailImage( $image, $dstUrl, false, [
                'width' => $width,
                'height' => $height,
                'page' => $page,
            ] );
        }
 
        if ( !wfMkdirParents( dirname( $dstPath ), null, __METHOD__ ) ) {
            return $this->doThumbError( $width, $height, 'thumbnail_dest_directory' );
        }
 
        // Thumbnail extraction is very inefficient for large files.
        // Provide a way to pool count limit the number of downloaders.
        if ( $image->getSize() >= 1e7 ) { // 10MB
            $work = new PoolCounterWorkViaCallback( 'GetLocalFileCopy', sha1( $image->getName() ),
                [
                    'doWork' => function () use ( $image ) {
                        return $image->getLocalRefPath();
                    }
                ]
            );
            $srcPath = $work->execute();
        } else {
            $srcPath = $image->getLocalRefPath();
        }
 
        if ( $srcPath === false ) { // could not download original
            return $this->doThumbError( $width, $height, 'filemissing' );
        }
 
        $cmd = '(' . wfEscapeShellArg(
            $wgPdfProcessor,
            "-sDEVICE=jpeg",
            "-sOutputFile=-",
            "-dFirstPage={$page}",
            "-dLastPage={$page}",
            "-dSAFER",
            "-r{$wgPdfHandlerDpi}",
            "-dBATCH",
            "-dNOPAUSE",
            "-q",
            $srcPath
        );
        $cmd .= " | " . wfEscapeShellArg(
            $wgPdfPostProcessor,
            "-depth",
            "8",
            "-quality",
            $wgPdfHandlerJpegQuality,
            "-resize",
            $width,
            "-",
            $dstPath
        );
        $cmd .= ")";
 
        wfDebug( __METHOD__ . ": $cmd\n" );
        $retval = '';
        $err = wfShellExecWithStderr( $cmd, $retval );
 
        $removed = $this->removeBadFile( $dstPath, $retval );
 
        if ( $retval != 0 || $removed ) {
            wfDebugLog( 'thumbnail',
                sprintf( 'thumbnail failed on %s: error %d "%s" from "%s"',
                wfHostname(), $retval, trim( $err ), $cmd ) );
            return new MediaTransformError( 'thumbnail_error', $width, $height, $err );
        } else {
            return new ThumbnailImage( $image, $dstUrl, $dstPath, [
                'width' => $width,
                'height' => $height,
                'page' => $page,
            ] );
        }
    }
 
    private function getPdfImage( $image, $path ) {
        if ( !$image ) {
            $pdfimg = new PdfImage( $path );
        } elseif ( !isset( $image->pdfImage ) ) {
            $pdfimg = $image->pdfImage = new PdfImage( $path );
        } else {
            $pdfimg = $image->pdfImage;
        }
 
        return $pdfimg;
    }
 
    private function getMetaArray( $image ) {
        if ( isset( $image->pdfMetaArray ) ) {
            return $image->pdfMetaArray;
        }
 
        $metadata = $image->getMetadata();
 
        if ( !$this->isMetadataValid( $image, $metadata ) ) {
            wfDebug( "Pdf metadata is invalid or missing, should have been fixed in upgradeRow\n" );
            return false;
        }
 
        $work = new PoolCounterWorkViaCallback(
            'PdfHandler-unserialize-metadata',
            $image->getName(),
            [
                'doWork' => function () use ( $image, $metadata ) {
                    Wikimedia\suppressWarnings();
                    $image->pdfMetaArray = unserialize( $metadata );
                    Wikimedia\restoreWarnings();
                },
            ]
        );
        $work->execute();
 
        return $image->pdfMetaArray;
    }
 
    public function getImageSize( $image, $path ) {
        return $this->getPdfImage( $image, $path )->getImageSize();
    }
 
    public function getThumbType( $ext, $mime, $params = null ) {
        global $wgPdfOutputExtension;
        static $mime;
 
        if ( !isset( $mime ) ) {
            $magic = MediaWiki\MediaWikiServices::getInstance()->getMimeAnalyzer();
            $mime = $magic->guessTypesForExtension( $wgPdfOutputExtension );
        }
        return [ $wgPdfOutputExtension, $mime ];
    }
 
    public function getMetadata( $image, $path ) {
        return serialize( $this->getPdfImage( $image, $path )->retrieveMetaData() );
    }
 
    public function isMetadataValid( $image, $metadata ) {
        if ( !$metadata || $metadata === serialize( [] ) ) {
            return self::METADATA_BAD;
        } elseif ( strpos( $metadata, 'mergedMetadata' ) === false ) {
            return self::METADATA_COMPATIBLE;
        }
        return self::METADATA_GOOD;
    }
 
    public function formatMetadata( $image, $context = false ) {
        $meta = $image->getMetadata();
 
        if ( !$meta ) {
            return false;
        }
        Wikimedia\suppressWarnings();
        $meta = unserialize( $meta );
        Wikimedia\restoreWarnings();
 
        if ( !isset( $meta['mergedMetadata'] )
            || !is_array( $meta['mergedMetadata'] )
            || count( $meta['mergedMetadata'] ) < 1
        ) {
            return false;
        }
 
        // Inherited from MediaHandler.
        return $this->formatMetadataHelper( $meta['mergedMetadata'], $context );
    }
 
    public function pageCount( File $image ) {
        $info = $this->getDimensionInfo( $image );
 
        return $info ? $info['pageCount'] : false;
    }
 
    public function getPageDimensions( File $image, $page ) {
        $index = $page; // MW starts pages at 1, as they are stored here
 
        $info = $this->getDimensionInfo( $image );
        if ( $info && isset( $info['dimensionsByPage'][$index] ) ) {
            return $info['dimensionsByPage'][$index];
        }
 
        return false;
    }
 
    protected function getDimensionInfo( File $file ) {
        $cache = ObjectCache::getMainWANInstance();
        return $cache->getWithSetCallback(
            $cache->makeKey( 'file-pdf', 'dimensions', $file->getSha1() ),
            $cache::TTL_INDEFINITE,
            function () use ( $file ) {
                $data = $this->getMetaArray( $file );
                if ( !$data || !isset( $data['Pages'] ) ) {
                    return false;
                }
                unset( $data['text'] ); // lower peak RAM
 
                $dimsByPage = [];
                $count = intval( $data['Pages'] );
                for ( $i = 1; $i <= $count; $i++ ) {
                    $dimsByPage[$i] = PdfImage::getPageSize( $data, $i );
                }
 
                return [ 'pageCount' => $count, 'dimensionsByPage' => $dimsByPage ];
            },
            [ 'pcTTL' => $cache::TTL_INDEFINITE ]
        );
    }
 
    public function getPageText( File $image, $page ) {
        $data = $this->getMetaArray( $image );
        if ( !$data || !isset( $data['text'] ) || !isset( $data['text'][$page - 1] ) ) {
            return false;
        }
        return $data['text'][$page - 1];
    }
 
    public function getWarningConfig( $file ) {
        return [
            'messages' => self::$messages,
            'link' => '//www.mediawiki.org/wiki/Special:MyLanguage/Help:Security/PDF_files',
            'module' => 'pdfhandler.messages',
        ];
    }
 
    public static function registerWarningModule( &$resourceLoader ) {
        $resourceLoader->register( 'pdfhandler.messages', [
            'messages' => array_values( self::$messages ),
        ] );
    }
}