searchanddisplace-core/app/SearchDisplace/Convertor/Convertor.php

<?php

namespace App\SearchDisplace\Convertor;

use Symfony\Component\Process\Process;
use Symfony\Component\Process\Exception\ProcessFailedException;

/**
 * Convert documents from formats supported by Libre Office
 */

class Convertor {
    /**
     * @param $to desired file format
     * @param $document absolute file path
     * @param $tmp - if true file will be saved to tmp directory for download
     *
     * @return string $path to converted file
     */
    public static function convert($to, $document, $tmp = false)
    {
        $path = pathinfo($document);
        $dir = $path['dirname'];
        $original = $dir . '/' . $path['basename'];
        if(!$tmp) {
            $folder = $dir . '/';
        } else {
            $folder = storage_path('app/tmp/');
        }

        $process = new Process(
            [
                'soffice',
                '--convert-to',
                $to,
                $original,
                '--outdir',
                $folder
            ], base_path(),
            [
                'HOME' => base_path()
            ]
        );
        $process->run();

        if (!$process->isSuccessful()) {
            throw new ProcessFailedException($process);
        }

        return $path['filename'] . '.' . $to;
    }
}