PHPMailer SMTP Gmail authentification error - oauth-2.0

Question

I'm sending emails using PHPMailer 5.2.10 with the next code:
function SendGmail($to,$subj,$body)
{
$mail = new PHPMailer(); // create a new object
$mail->IsSMTP(); // enable SMTP
$mail->SMTPDebug = 1; // debugging: 1 = errors and messages, 2 = messages only
$mail->SMTPAuth = true; // authentication enabled
$mail->SMTPSecure = 'ssl'; // "ssl" secure transfer enabled REQUIRED for GMail
$mail->Host = "smtp.gmail.com";
$mail->Port = 465; // 465 or 587
$mail->IsHTML(true);
$mail->Username = "admin#mydomain.ru";
$mail->Password = "********";
$mail->SetFrom("admin#mydomain.ru");
$mail->Subject = $subj;
$mail->Body = $body;
$mail->AddAddress($to);
return $mail->Send();
}
Note: we use Google Apps, so the mail domain is not google.com, but some other, let's say, mydomain.ru.
Everything was fine until Google had recently implemented another "security enhancement" (AFAIK forcing OAuth2 authorisation). Now PHPMailer->Send() returns the following text:
2015-05-12 06:49:15 CLIENT -> SERVER: EHLO 127.0.0.1
2015-05-12 06:49:15 CLIENT -> SERVER: AUTH LOGIN
2015-05-12 06:49:15 CLIENT -> SERVER: [some base64 string]
2015-05-12 06:49:15 CLIENT -> SERVER: [some base64 string]
2015-05-12 06:49:16 SMTP ERROR: Password command failed: 535-5.7.8 Username and Password not accepted. Learn more at 535 5.7.8 http://support.google.com/mail/bin/answer.py?answer=14257 u10sm3566045lbb.30 - gsmtp
2015-05-12 06:49:16 SMTP Error: Could not authenticate.
2015-05-12 06:49:16 CLIENT -> SERVER: QUIT
2015-05-12 06:49:16 SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting bool(false) Done!
Ok, I go to http://support.google.com/mail/bin/answer.py?answer=14257 and doing the following:
Logging to this account via web interface - everything's Ok,
Opening this link in browser: http://www.google.com/accounts/DisplayUnlockCaptcha - google says everything is Ok,
Opening this link: https://support.google.com/accounts/answer/6010255 and then this link: https://www.google.com/settings/security/lesssecureapps where I see the following:
"Access for less secure apps: * Turn off / * Turn on" - for normal gmail account,
("This setting is inaccessible for google apps accounts") - for google apps account (not the exact text but my translation from russian as google shows it).
Yes, I have tried both SSL and TLS, 485 or 587 ports and everything else I've found on stackoverflow.com and here: https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting . Nothing helped.
PHPMailer troubleshooting page suggests to use "an OAuth2 client class": http://www.phpclasses.org/package/7700-PHP-Authorize-and-access-APIs-using-OAuth.html - but I have no idea of how to integrate it into PHPMailer and why it's not integrated yet by PHPMailer developers (this class is under BSD license), while it's necessary now for one of the most popular mail servers. I found no documentation for this OAuth2 about integrating it into PHPMailer, and I'm sure I can't do it myself - my PHP knowledge is poor.
The question is:
How can I avoid this goddamn OAuth2 and send emails as I did it before this "security enhancement" (for google apps account)? --OR:
How to easily integrate OAuth2 class mentioned above into PHPMailer? --OR:
Are there any other easy-to-use PHP solutions to send emails using gmail?
Lots of thanks in advance.

Answer 1

Thank you for reading the docs, it's much appreciated! The problem is that google has imposed this complicated authentication mechanism without much regard for its users, as you have experienced. It doesn't improve security because ultimately you still have to submit a username and password over SSL to get your token. OAuth is an authorisation (what you can do) protocol, but google are using it indirectly as an authentication (who you are) protocol.
The reason that nobody has implemented it is that while it's very clever, OAuth is generally unpleasant and confusing to work with, which is why we'd be very happy if someone got around to implementing it!
This article is very helpful and might form the basis of a PHPMailer implementation. Though that adds a dependency on ZF2, the principles will be the same for any other OAuth implementation such as the one from PHPClasses I linked to or this one.
Sorry I can't be much more help on this.
Update: PHPMailer now supports OAuth for gmail. This article describes how to use it, and yes it is still quite unpleasant!

Answer 2

How can I avoid this goddamn OAuth2 and send emails as I did it
before this "security enhancement" (for google apps account)?
You can't. Unlike regular Google, Google Apps does not allow "less secure apps". And once your account has been flagged for extra security, you must switch to OAuth2.
How to easily integrate OAuth2 class mentioned above into PHPMailer?
You can't. Like the Thunderbird team, there is some pretty strong bias against OAuth2 in the PHP Mailer team. IMO, OAuth2 is a big improvement for email.
Are there any other easy-to-use PHP solutions to send emails
using gmail?
Yes. My solution for my own SMTP project, Postman, was to switch from PHP Mailer to Zend_Mail for OAuth2. Zend_Mail has had native OAuth2 support for quite a while.

Answer 3

Oops, that was my mistake, I've been editing the code in wrong place, not in the one it was executed from.
Strange, but in spite of OAuth2 and other google surprises, i had not to change anything to make old code work (just update password).