PHPMailer::msgHTML( string $message, string $basedir = '', bool|callable $advanced = false ): string

4603    public function msgHTML($message, $basedir = '', $advanced = false)4604    {4605        preg_match_all('/(?<!-)(src|background)=["\'](.*)["\']/Ui', $message, $images);4606        if (array_key_exists(2, $images)) {4607            if (strlen($basedir) > 1 && '/' !== substr($basedir, -1)) {4608                //Ensure $basedir has a trailing /4609                $basedir .= '/';4610            }4611            foreach ($images[2] as $imgindex => $url) {4612                //Convert data URIs into embedded images4613                //e.g. "data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw=="4614                $match = [];4615                if (preg_match('#^data:(image/(?:jpe?g|gif|png));?(base64)?,(.+)#', $url, $match)) {4616                    if (count($match) === 4 && static::ENCODING_BASE64 === $match[2]) {4617                        $data = base64_decode($match[3]);4618                    } elseif ('' === $match[2]) {4619                        $data = rawurldecode($match[3]);4620                    } else {4621                        //Not recognised so leave it alone4622                        continue;4623                    }4624                    //Hash the decoded data, not the URL, so that the same data-URI image used in multiple places4625                    //will only be embedded once, even if it used a different encoding4626                    $cid = substr(hash('sha256', $data), 0, 32) . '@phpmailer.0'; //RFC2392 S 24627 4628                    if (!$this->cidExists($cid)) {4629                        $this->addStringEmbeddedImage(4630                            $data,4631                            $cid,4632                            'embed' . $imgindex,4633                            static::ENCODING_BASE64,4634                            $match[1]4635                        );4636                    }4637                    $message = str_replace(4638                        $images[0][$imgindex],4639                        $images[1][$imgindex] . '="cid:' . $cid . '"',4640                        $message4641                    );4642                    continue;4643                }4644                if (4645                    //Only process relative URLs if a basedir is provided (i.e. no absolute local paths)4646                    !empty($basedir)4647                    //Ignore URLs containing parent dir traversal (..)4648                    && (strpos($url, '..') === false)4649                    //Do not change urls that are already inline images4650                    && 0 !== strpos($url, 'cid:')4651                    //Do not change absolute URLs, including anonymous protocol4652                    && !preg_match('#^[a-z][a-z0-9+.-]*:?//#i', $url)4653                ) {4654                    $filename = static::mb_pathinfo($url, PATHINFO_BASENAME);4655                    $directory = dirname($url);4656                    if ('.' === $directory) {4657                        $directory = '';4658                    }4659                    //RFC2392 S 24660                    $cid = substr(hash('sha256', $url), 0, 32) . '@phpmailer.0';4661                    if (strlen($basedir) > 1 && '/' !== substr($basedir, -1)) {4662                        $basedir .= '/';4663                    }4664                    if (strlen($directory) > 1 && '/' !== substr($directory, -1)) {4665                        $directory .= '/';4666                    }4667                    if (4668                        $this->addEmbeddedImage(4669                            $basedir . $directory . $filename,4670                            $cid,4671                            $filename,4672                            static::ENCODING_BASE64,4673                            static::_mime_types((string) static::mb_pathinfo($filename, PATHINFO_EXTENSION))4674                        )4675                    ) {4676                        $message = preg_replace(4677                            '/' . $images[1][$imgindex] . '=["\']' . preg_quote($url, '/') . '["\']/Ui',4678                            $images[1][$imgindex] . '="cid:' . $cid . '"',4679                            $message4680                        );4681                    }4682                }