SproutCMS

source of /sprout/Helpers/FileConvert.php

<?php
/*
 * Copyright (C) 2017 Karmabunny Pty Ltd.
 *
 * This file is a part of SproutCMS.
 *
 * SproutCMS 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.
 *
 * For more information, visit <http://getsproutcms.com>.
 */
 
namespace Sprout\Helpers;
 
use RuntimeException;
use InvalidArgumentException;
use Sprout\Exceptions\FileConversionException;
 
/**
 * Converter between various file types
 *
 * For all features to work, the following programs need to be installed:
 * - convert (e.g. from the graphicsmagick-imagemagick-compat Debian package)
 * - exiftool (e.g. from the libimage-exiftool-perl Debian package)
 * - libreoffice (e.g. from the libreoffice-common Debian package)
 */
class FileConvert
{
    /**
     * Validates that an output file extension is of a valid format
     *
     * @param string $ext The output extension
     * @throws InvalidArgumentException IF the extension is invalid
     */
    private static function validateExtension($ext)
    {
        if (!preg_match('/^[a-z]{3,4}$/i', $ext)) {
            throw new InvalidArgumentException('Output extension must be 3-4 alphabetic characters');
        }
    }
 
    /**
     * Convert file using LibreOffice
     *
     * @param string $in_file Input filename, with full path
     * @param string $out_ext Extension to convert file to, e.g. "pdf", "jpg", "txt".
     *        Note that spreadsheets cannot be directly converted to images, but can be converted to PDFs which can
     *        then be converted using {@see FileConvert::imagemagick}
     * @return string Destination file in temp dir
     * @throws InvalidArgumentException The $out_ext argument has an invalid format
     * @throws RuntimeException LibreOffice isn't installed/accessible to PHP
     * @throws FileConversionException LibreOffice failed to convert the file
     */
    public static function libreoffice($in_file, $out_ext)
    {
        static::validateExtension($out_ext);
 
        $out_arg = escapeshellarg(APPPATH . 'temp/');
        $tmp_arg = escapeshellarg($in_file);
        $cmd = "libreoffice --headless --convert-to {$out_ext} --outdir {$out_arg} {$tmp_arg} 2>&1";
 
        $output = [];
        $return_code = null;
        exec($cmd, $output, $return_code);
 
        if ($return_code !== 0) {
            if (!self::installed('libreoffice')) {
                throw new RuntimeException("Program 'libreoffice' not installed - try the 'libreoffice-common' package");
            }
            throw new FileConversionException('Libreoffice converting to ' . $out_ext . ' failed - exec() error');
        }
 
        $dest_file = APPPATH . 'temp/' . File::getNoext(basename($in_file)) . '.' . $out_ext;
        if (!file_exists($dest_file)) {
            throw new FileConversionException('Libreoffice converting to ' . $out_ext . ' failed - destination file "' . $dest_file . '" not found');
        }
 
        return $dest_file;
    }
 
 
    /**
     * Convert file using ImageMagick
     *
     * @throws Exception Conversion failure
     * @param string $in_file Input filename, with full path
     * @param string $out_ext Extension to convert file to, e.g. "png", "jpg".
     * @param int $page_index Page number of document, 0-based (applies to PDFs and other page-based documents)
     * @param int $density DPI
     * @return string Destination file in temp dir
     * @throws InvalidArgumentException The $out_ext argument has an invalid format
     * @throws RuntimeException ImageMagick isn't installed/accessible to PHP
     * @throws FileConversionException ImageMagick failed to convert the file
     */
    public static function imagemagick($in_file, $out_ext, $page_index = 0, $density = 400) {
        $page_index = (int) $page_index;
        $density = (int) $density;
 
        static::validateExtension($out_ext);
 
        $out_file = APPPATH . 'temp/' . File::getNoext(basename($in_file)) . '_' . Sprout::randStr(4) . '.' . $out_ext;
 
        $in_arg = escapeshellarg($in_file . '[' . $page_index . ']');
        $out_arg = escapeshellarg($out_file);
 
        $cmd = "convert -background white -alpha background -alpha off -colorspace RGB -quality 100% -density {$density} -resize 25% {$in_arg} {$out_arg} 2>&1";
 
        $output = [];
        $return_code = null;
        exec($cmd, $output, $return_code);
 
        if ($return_code !== 0) {
            if (!self::installed('convert')) {
                throw new RuntimeException("Program 'convert' not installed - try the 'graphicsmagick-imagemagick-compat' package");
            }
            throw new FileConversionException('Imagemagick converting to ' . $out_ext . ' failed - exec() error');
        }
 
        if (!file_exists($out_file)) {
            throw new FileConversionException('Imagemagick converting to ' . $out_ext . ' failed - destination file not found');
        }
 
        return $out_file;
    }
 
 
    /**
     * Use 'exiftool' to determine the number of pages in a file
     *
     * @throws Exception
     * @param string $filename Server filename
     * @return int Number of pages
     * @throws RuntimeException exiftool isn't installed/accessible to PHP
     * @throws FileConversionException exiftool was unable to determine the page count
     */
    public static function getPageCount($filename) {
        $cmd = 'exiftool -json ' . escapeshellarg($filename);
 
        $output = [];
        $return_code = null;
        exec($cmd, $output, $return_code);
 
        if ($return_code !== 0) {
            if (!self::installed('exiftool')) {
                throw new RuntimeException("Program 'exiftool' not installed - try the 'libimage-exiftool-perl' package");
            }
            throw new FileConversionException('Exiftool failed - exec() error');
        }
 
        $data = json_decode(implode('', $output));
        if (isset($data[0]->PageCount)) {
            return $data[0]->PageCount;
        }
        if (isset($data[0]->Pages)) {
            return $data[0]->Pages;
        }
 
        if (strtolower(File::getExt($filename)) === 'pdf') {
            throw new FileConversionException('Unable to determine page count');
        }
 
        // Exiftool couldn't process this file. Convert to PDF and try again.
        $dest_file_pdf = self::libreoffice('pdf', 'pdf', $filename);
        $count = self::getPageCount($dest_file_pdf);
        unlink($dest_file_pdf);
        return $count;
    }
 
 
    /**
     * Checks to see that a conversion program is installed
     *
     * @param string $program The program name; 'libreoffice', 'convert' (i.e. ImageMagick), 'exiftool'
     * @return bool True if the program is installed
     */
    public static function installed($program)
    {
        $cmd = 'which ' . escapeshellarg($program);
 
        $out = [];
        $return_code = null;
        exec($cmd, $out, $return_code);
 
        if ($return_code !== 0) {
            return false;
        }
        return true;
    }
}