UseSMTPUTF8 deprecated?

[tnbnicer]

Hi. Likely I'm going about it not quite right, but I succeeded in sending a message with a Unicode address to and from a server that nominally supports SMTPUTF8 using PHPMailer7.

sender = me@gmail.com
recipient = me+bücher@gmail.com

if ($mail->has8bitChars($email)) {
	$mail->CharSet = 'UTF-8';
	$mail->UseSMTPUTF8 = true;
}

I skipped validation. (Only a test.)

I did not find much (or any) documentation on PHPMailer::UseSMTPUTF8, without admittedly looking very hard.

When previously I attempted to send with the same parameters as above using PHPMailer6.60, A) debugging produced a warning that UseSMTPUTF8 is deprecated, and B) no email was sent. PHP7 sent the email to me+bücher@gmail.com. It arrived as me+bücher@gmail.com. Congratulations to the developer, and not 'deprecated'!

Questions: Am I doing it right? Why no longer deprecated? Why deprecated in the first place?

Comment: You cannot check if the server supports Unicode headers. A recipient will be aware however that if the email address is wrong, reply emails will end up being returned to the sending server marked 'Mail delivery failures'.

[tnbnicer]

After some more testing and validating this time, I came up with the following code to enable both Unicode and punycode, given that they are mutually exclusive.

if ($mail->has8bitChars($email)) {
	$mail->CharSet = 'UTF-8';
	$puny=explode('@', $email, 2);
	if ($mail->has8bitChars($puny[0])) {
		$smtputf8 = ($mail->validateAddress(idn_to_ascii($puny[0]).'@'.$puny[1], 'auto')) ? true : false;
	}
	if ($smtputf8) {
		$email = $vmail;
	} else {
		$email = $mail->punyencodeAddress($email).'';
	}
}

$vmail is the unmodified inputted email address.

Note: I dropped UseSMTPUTF8, which apparently has no effect true or false.

Please correct me, if this is in error. The bottom line is, you need to determine first that the address is SMTPUTF8 in order to validate.

if (!$smtputf8&&!$mail->validateAddress($email, 'auto')) : $errvalues = 2;

[Synchro]

You're overthinking this. If you use a mail service that supports SMTPUTF8 for sending, and you have an address that needs it, it's reasonably safe to assume that the server at the receiving end is going to support it too. If that's not the case, it's not your problem. Just validate the address and send without checking for any of this punycode stuff. If it fails to send, catch the error and move on; you don't need to care.

[tnbnicer]

The situation is that me+bäcker@gmail.com does not validate because of the local part.

In my opinion the code is ok. I'm running it locally from WAMP. I could put it online, if you wish, and send you a link on a private channel, so you could try out other valid Unicode addresses using the live form. The catch is:

if (!$mail->validateAddress($email, 'auto')) : $errvalues = 2;

gets you the error. It must be:

if (!$smtputf8&&!$mail->validateAddress($email, 'auto')) : $errvalues = 2;

to work, to send.

I have about another half hour this morning in which to try things. This evening I can resume the testing. Still, I don't see what I could be doing differently.

[Synchro]

The UseSMTPUTF8 property is set dynamically in preSend. It will automatically be assigned the appropriate value – setting it yourself will have no effect.

By default PHPMailer uses PHP's built-in filter_var validator, which does not handle SMTPUTF8 addresses. If you're expecting to use addresses that require SMTPUTF8, the validator needs to expect that, and until you've called addAddress and set CharSet, it can't know which validator to use automatically. So if you're calling it in isolation, you need to tell it which validator pattern to use beforehand. Add this near the top of your script, before you try to add any addresses:

    PHPMailer::$validator = 'eai';

This is covered in the docs for validateAddress, and in the code.

[tnbnicer]

That helps. Thank you.

$mail->validateAddress($email, 'eai') validates me+gebrüder@gmail.com. $mail->validateAddress($email, 'auto') fails the validation.

You are probably right about punycode conversion being unnecessary also. Gmail sends addresses like info@网站.亚洲. It depends on whether I continue to send the emails via Gmail. If instead I decide to stay with my hosting provider's mail server, it requires punycode. info@网站.亚洲 -> info@xn--5tzm5g.xn--jlqt95e.

The receiving mail server should then be able to parse info@xn--5tzm5g.xn--jlqt95e, so it will arrive in the inbox of info@网站.亚洲.

I have to fool around with Gmail some more. It may not be 100% reliable. Sometimes I get SMTP error messages, where the email is not sent. I'd post the error message here, but at the moment I can't reproduce it.

Either way, that SMTPUTF8 is now supported by PHPMailer is nothing short of terrific. !!!