Is there a standard and an implementation for Icalendar event RSVP

Question

The summary is that I am now implementing an event confirmation system and can't find the right format for the ICalendar replies. Therefore I wonder if there is an example out there of complete REPLY message and maybe a PHP library that would wrap it all?

Now for the details, we get external emails including event invitations asking for RSVP. Here is an excerpt of the iCal file:

ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE;CN="'user@company.com'":MAILTO:user@company.com ORGANIZER;CN="Organ Izer":MAILTO:organizer@company.com

I couldn't find the reply standard to send the RSVP to the organizer. The RFC 2447 mentions "ATTSTAT" and "PARTSTAT" parameter.

By trying to mail the following message to Google calendar the event is not being updated.

$headers = "Content-Type:text/calendar; Content-Disposition: inline; charset=utf-8;\r\n";
$headers .= "Content-Type: text/plain;charset=\"utf-8\"\r\n";
$headers .= 'BEGIN:VCALENDAR
VERSION:2.0
METHOD:REPLY
BEGIN:VEVENT
ORGANIZER;CN=JCharles:mailto:abcdef@gmail.com
UID:oc7ae7537999onscsivg8km123@google.com
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=CONFIRMED;RSVP=
 TRUE;CN=jc@company.se;X-NUM-GUESTS=0:mailto:jc@company.se
LOCATION:
SEQUENCE:1
END:VEVENT
END:VCALENDAR';

mail('abcdef@gmail.com', 'Accepted:', "Event accepted", $headers);

Is there anything wrong with the Ical message or with the method in itself? Is this the way the event replies are supposed to be sent?

Answer 1

The following code will work with google calendar. The attachment is processed by gmail and acceptance is cascaded to the event.

$vcal = 'BEGIN:VCALENDAR
PRODID:-//EXAMPLE.NU//SE
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:REPLY
BEGIN:VEVENT
DTSTART:20101215T160000Z
DTEND:20101215T170000Z
DTSTAMP:'.date('Ymd\THis\Z').'
ORGANIZER;CN=Jean-Charles:mailto:example@gmail.com
UID:u2coh5g3bppo2d2o3t@google.com
ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;
 CN=user@example.se:mailto:user@example.se
CREATED:19000101T120000Z
DESCRIPTION:äåóö
LAST-MODIFIED:'.date('Ymd\THis\Z').'
LOCATION:
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:a new test
TRANSP:OPAQUE
END:VEVENT
END:VCALENDAR
';

$vcal = utf8_encode($vcal);

require('lib/phpmailer/class.phpmailer.php');
$mail = new PHPMailer();
$mail->AddAddress('example@gmail.com', 'Jean-Charles');
$mail->Body = "HTML BODY";
$mail->AltBody = "Text body";
$mail->Subject = "Email title";
$mail->Sender = "User Name";
$mail->FromName = "user@example.se";
$mail->AddStringAttachment($vcal, 'meeting.ics', "base64", "text/calendar");
$mail->Send();

The important bits are

• Content-type : text/calendar
• METHOD:REPLY
• PARTSTAT:ACCEPTED|DECLINED
• UID

I am not sure that it is necessary to send back all redundant information (description, summary, dtend, dtstart)

Answer 2

The following solution worked for me:

$mail->Subject = $name;
$mail->Body = $description; 
$mail->AltBody = $body; // ical format
$mail->Ical = $message; // ical format

This methods does not attach the ical format.