sendMessage

  /**
     * @param $sender string sender email address
     * @param $to string recipient email address
     * @param $subject string email subject
     * @param $messageText string email text
     * @return Google_Service_Gmail_Message
     */
    function createMessage($sender, $to, $subject, $messageText, $file = null)
    {
        $message = new Google_Service_Gmail_Message($this->client);
        $boundary = uniqid(rand(), true);
        $rawMessageString = "From: <{$sender}>\r\n";
        $rawMessageString .= "To: <{$to}>\r\n";
        $subjectCharset = $charset = 'utf-8';
        $rawMessageString .= 'Subject: =?utf-8?B?' . base64_encode($subject) . "?=\r\n";
        $rawMessageString .= "MIME-Version: 1.0\r\n";
        $rawMessage = strtr(base64_encode($rawMessageString), array('+' => '-', '/' => '_'));
        if (isset($file) and $file != null) {
            $filePath = $file->getRealPath();
            //$finfo = finfo_open(FILEINFO_MIME_TYPE); // return mime type ala mimetype extension
            $mimeType = $file->getMimeType();
            $fileName = $file->getClientOriginalName();
            $fileData = base64_encode(file_get_contents($filePath));
            $fileData = base64_encode($file);
            $rawMessageString .= "\r\n--{$boundary}\r\n";
            $rawMessageString .= 'Content-Type: ' . $mimeType . '; name="' . $fileName . '";' . "\r\n";
            $rawMessageString .= 'Content-ID: <' . $sender . '>' . "\r\n";
            $rawMessageString .= 'Content-Transfer-Encoding: base64' . "\r\n\r\n";
            $rawMessageString .= chunk_split(base64_encode($fileData), 76, "\n") . "\r\n";
            $rawMessageString .= '--' . $boundary . "\r\n";
            $rawMessageString .= "\r\n--{$boundary}\r\n";
            $rawMessageString .= 'Content-Type: text/plain; charset=' . $charset . "\r\n";
            $rawMessageString .= 'Content-Transfer-Encoding: 7bit' . "\r\n\r\n";
            // $strRawMessage .= $strMailTextVersion . "\r\n";

            $rawMessageString .= "--{$boundary}\r\n";
            $rawMessageString .= 'Content-Type: text/html; charset=' . $charset . "\r\n";
            $rawMessageString .= 'Content-Transfer-Encoding: quoted-printable' . "\r\n\r\n";
            $rawMessageString .= $messageText . "\r\n";
        } else {

            $rawMessageString .= "Content-Type: text/html; charset=utf-8\r\n";
            $rawMessageString .= 'Content-Transfer-Encoding: quoted-printable' . "\r\n\r\n";
        }
        $message->setRaw($rawMessage);
        return $message;
    }

    function createMessage($sender, $to, $subject, $messageText)
    {
        $message = new Google_Service_Gmail_Message($this->client);
        $rawMessageString = "From: <{$sender}>\r\n";
        $rawMessageString .= "To: <{$to}>\r\n";
        $rawMessageString .= 'Subject: =?utf-8?B?' . base64_encode($subject) . "?=\r\n";
        $rawMessageString .= "MIME-Version: 1.0\r\n";
        $rawMessageString .= "Content-Type: text/html; charset=utf-8\r\n";
        $rawMessageString .= 'Content-Transfer-Encoding: quoted-printable' . "\r\n\r\n";
        $rawMessageString .= "{$messageText}\r\n";
        $rawMessage = strtr(base64_encode($rawMessageString), array('+' => '-', '/' => '_'));
        $message->setRaw($rawMessage);
        return $message;
    }