Custom Header for Attachments

[jfade]

I'm having an issue with needing to add custom headers for attachments to an email. I'm generating and attaching calendar appointments (meeting requests) and sending them to the users of my web application. It works perfectly for Gmail users. However, for those who are using Outlook, it does not behave as expected. After some research (and finding a related issue on the nodejs Sendgrid library) it appears that Outlook expects something additional in the header with the attachment. This is the header generated by Outlook for a meeting invite:

Content-Type: text/calendar; charset="utf-8"; method=REQUEST

and this is what I can get from SendGrid:

Content-Type: text/calendar; charset=utf-8; name="1187.ics"

It appears that, in order for me to get it to behave properly, I have to add method=REQUEST to the Content-Type header on the attachment alone. (Having the attachment name does not seem like it's going to be an issue.)

I'm currently using the v2 library. The nodejs ticket referenced above says this isn't going to be an issue with v3, but after looking at the (just published) v3 for php, I don't see the ability to change the header beyond setting the content type. Is this something that can be added or am I just missing the fact that this is doable in some other way? Thanks!

[thinkingserious]

Thanks for the question @jfade, we will take a look and see if we have a solution for you.

[jfade]

Thank you! I'm hopeful we find a solution, as I much prefer SendGrid to the other services I've looked at and used. I'll keep an eye out for an update from you. Appreciate it!

[thinkingserious]

Hello @jfade,

Have you given this a try using the updated library?

You can try over-riding the header like this: https://github.com/sendgrid/sendgrid-php/blob/master/test/unit/SendGridTest.php#L1075

[chipallen2]

Do you have a code snippet on how that would work in the new library?

I'm getting this error when I try it:

The attachment type cannot contain ';', or CRLF characters.

My code is:

$attachment->setType('text/calendar; charset="UTF-8"; method=REQUEST');

[thinkingserious]

@chipallen2,

I have not been able to get this to work either. I've put in a ticket with the API team.

Also, I added your vote to this issue to help move it up the queue.

Thanks!

[jfade]

@chipallen2, @thinkingserious, sorry for not participating sooner. However, I did end up getting a workaround figured out that is not ideal, but let me proceed immediately with getting things working as I needed to. It wasn't quite what I originally wanted, but it DOES work. Maybe this will help you, @chipallen2.

It did require another library, however, so I would still like for the method in the Sendgrid PHP library to be updated. Having to use and maintain additional libraries is not something I'd like to deal with long term.

I utilized the PHPMailer library: https://github.com/PHPMailer/PHPMailer

From there, I was able to create and use SendGrid SMTP credentials to send the email like so:

$message = file_get_contents('/path/to/calendarfile.ics');
$mail = new PHPMailer;
//$mail->SMTPDebug = 3;                               // Enable verbose debug output
$mail->isSMTP();                                      // Set mailer to use SMTP
$mail->Host = 'smtp.sendgrid.net';  // Specify main and backup SMTP servers
$mail->SMTPAuth = true;                               // Enable SMTP authentication
$mail->Username = 'XXX';                 // SMTP username
$mail->Password = 'XXX';                           // SMTP password
$mail->SMTPSecure = 'tls';                            // Enable TLS encryption, `ssl` also accepted
$mail->Port = 587;                                    // TCP port to connect to
$mail->setFrom('fake@fake.com', 'Fake Company Meetings');
$mail->addAddress($apptWith);     // Add a recipient, set earlier
$mail->isHTML(false);                                  // Set email format as NOT HTML
$mail->Subject = $subject; //Subject variable, declared earlier
$mail->Body    = $message; //Message variable, set earlier
$mail->ContentType = 'text/calendar; method=REQUEST'; //It appears that we can just set whatever here, just leave the trailing ; off as that's added by the library... I do wonder if this is technically unexpected behavior that the developers of PHPMailer wouldn't want, but it works, so I won't complain.

if(!$mail->send()) {
    echo 'Message could not be sent.';
    echo 'Mailer Error: ' . $mail->ErrorInfo;
} else {
    echo 'Message has been sent';
}

It isn't quite perfect, and it's not quite the original method I wanted that more closely mirrors what Outlook actually does in most cases. However, in some instances, Outlook will send what would've been the .ics attachment contents as the body of the email (and setting the content type of the email) instead of attaching the file and setting its content type.

Hopefully that's clear enough, and hopefully it may help... But again, it would be nice if the $attachment->setType() method would allow for the content type to be set as needed for the more detailed calendar invite message.

[thinkingserious]

Thanks for sharing a workaround!

Can we please send you some swag? Just email us at dx@sendgrid.com with your mailing address and T-shirt size.

[MihailRussu]

Are there any updates on this? I ran into same issue with sendgrid-python:

The attachment type cannot contain ';', or CRLF characters.

It would be great if we could use the ; character in set_type() or have a method allowing to append method=REQUEST to Content-Type.

[thinkingserious]

Ah @MihailRussu, I just responded to you on another thread. currently this issue is currently on our backlog and we have added your vote to help increase the priority for a solution.

[winzig]

We are now running into this issue as well. The Content-Type header should either accept a charset attribute being set, or (if it's feasible), the API should be able to detect the necessary encoding type and specify it internally. (An encoding guru would probably need to chime in as to whether or not this is feasible.)