public function createHeader()
{
$result = '';
if ('' == $this->MessageDate) {
$this->MessageDate = static::rfcDate();
}
$result .= $this->headerLine('Date', $this->MessageDate);
// To be created automatically by mail()
if ($this->SingleTo) {
if ('mail' != $this->Mailer) {
foreach ($this->to as $toaddr) {
$this->SingleToArray[] = $this->addrFormat($toaddr);
}
}
} else {
if (count($this->to) > 0) {
if ('mail' != $this->Mailer) {
$result .= $this->addrAppend('To', $this->to);
}
} elseif (count($this->cc) == 0) {
$result .= $this->headerLine('To', 'undisclosed-recipients:;');
}
}
$result .= $this->addrAppend('From', [[trim($this->From), $this->FromName]]);
// sendmail and mail() extract Cc from the header before sending
if (count($this->cc) > 0) {
$result .= $this->addrAppend('Cc', $this->cc);
}
// sendmail and mail() extract Bcc from the header before sending
if (($this->Mailer == 'sendmail' or $this->Mailer == 'qmail' or $this->Mailer == 'mail') and count($this->bcc) > 0) {
$result .= $this->addrAppend('Bcc', $this->bcc);
}
if (count($this->ReplyTo) > 0) {
$result .= $this->addrAppend('Reply-To', $this->ReplyTo);
}
// mail() sets the subject itself
if ('mail' != $this->Mailer) {
$result .= $this->headerLine('Subject', $this->encodeHeader($this->secureHeader($this->Subject)));
}
if ('' != $this->MessageID and preg_match('/^<.*@.*>$/', $this->MessageID)) {
$this->lastMessageID = $this->MessageID;
} else {
$this->lastMessageID = sprintf('<%s@%s>', $this->uniqueid, $this->serverHostname());
}
$result .= $this->headerLine('Message-ID', $this->lastMessageID);
if (!is_null($this->Priority)) {
$result .= $this->headerLine('X-Priority', $this->Priority);
}
if ('' == $this->XMailer) {
$result .= $this->headerLine('X-Mailer', 'PHPMailer ' . self::VERSION . ' (https://github.com/PHPMailer/PHPMailer)');
} else {
$myXmailer = trim($this->XMailer);
if ($myXmailer) {
$result .= $this->headerLine('X-Mailer', $myXmailer);
}
}
if ('' != $this->ConfirmReadingTo) {
$result .= $this->headerLine('Disposition-Notification-To', '<' . $this->ConfirmReadingTo . '>');
}
// Add custom headers
foreach ($this->CustomHeader as $header) {
$result .= $this->headerLine(trim($header[0]), $this->encodeHeader(trim($header[1])));
}
if (!$this->sign_key_file) {
$result .= $this->headerLine('MIME-Version', '1.0');
$result .= $this->getMailMIME();
}
return $result;
}