Pressbooks\Modules\Export\Epub\Epub201::zipEpub PHP Method

    protected function zipEpub($filename)
    {
        $zip = new \PclZip($filename);
        // Open Publication Structure 2.0.1
        // mimetype must be uncompressed, unencrypted, and the first file in the ZIP archive
        $list = $zip->create($this->tmpDir . '/mimetype', PCLZIP_OPT_NO_COMPRESSION, PCLZIP_OPT_REMOVE_ALL_PATH);
        if (0 == $list) {
            return false;
        }
        $files = array();
        foreach (new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($this->tmpDir)) as $file) {
            if (!$file->isFile()) {
                continue;
            }
            if ('mimetype' == $file->getFilename()) {
                continue;
            }
            $files[] = $file->getPathname();
        }
        $list = $zip->add($files, '', $this->tmpDir);
        if (0 == $list) {
            return false;
        }
        return true;
    }