Send calendar invite per email with java

Question

I'm trying to send calendar invites per email with java. The recipient gets the email but instead of being shown an invitation to accept or decline, the event is automatically added to his calendar.

I'm building the event/invite with ical4j.jar

private Calendar getInvite(Session session) {
    Calendar calendar = new Calendar();
    calendar.getProperties().add(Version.VERSION_2_0);
    calendar.getProperties().add(Method.REQUEST);

    VEvent event = new VEvent(
        new DateTime(sesion.getStartDate()), 
        new DateTime(sesion.getEndDate()), 
        session.getName());

    event.getProperties().add(Priority.MEDIUM);
    event.getProperties().add(Clazz.PUBLIC);

    try {
        UidGenerator ug = new UidGenerator("uidGen");
        Uid uid = ug.generateUid();
        event.getProperties().add(uid);
    } catch (SocketException e) {
        // Log things
    }

    for (Participant participant : session.getParticipants()) {
        Attendee attendee = new Attendee(URI.create("mailto:" + participant.getEmail()));
        attendee.getParameters().add(Role.OPT_PARTICIPANT);
        attendee.getParameters().add(new Cn(participant.getName()));
        attendee.getParameters().add(PartStat.NEEDS_ACTION);
        event.getProperties().add(attendee);
    }

    calendar.getComponents().add(event);

    return calendar;

}

And this is how I send the email:

public void sendEmail(String fromMail, String toMail, String subject, String text, net.fortuna.ical4j.model.Calendar calendar) {
    try {
        Session session = Session.getInstance(getMailProperties(), new javax.mail.Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(getUser(), getPassword());
            }
        });

        MimeMessage mimeMessage = new MimeMessage(session);
        mimeMessage.setHeader("Content-Transfer-Encoding:", "7bit");

        Address address = new InternetAddress(fromMail);
        mimeMessage.setFrom(address);

        mimeMessage.setSentDate(Calendar.getInstance().getTime());
        mimeMessage.setRecipients(Message.RecipientType.TO, toMail);

        mimeMessage.setSubject(subject);
        Calendar cal = Calendar.getInstance();
        mimeMessage.setSentDate(cal.getTime());

        Multipart multipart = new MimeMultipart("alternative");

        // First part - HTML readable text  
        MimeBodyPart msgHtml = new MimeBodyPart();
        msgHtml.setContent(text, "text/html; charset=UTF-8");

        multipart.addBodyPart(msgHtml);

        if (calendar != null) {
            // Another part for the calendar invite
            MimeBodyPart invite = new MimeBodyPart();
            invite.setHeader("Content-Class", "urn:content-  classes:calendarmessage");
            invite.setHeader("Content-ID", "calendar_message");
            invite.setHeader("Content-Disposition", "inline");
            invite.setContent(calendar.toString(), "text/calendar");
            multipart.addBodyPart(invite);
        }

        mimeMessage.setContent(multipart);

        Transport.send(mimeMessage);

    } catch (Exception e) {
        // Log things
    }

}

But when I get the email (in gmail), I see no invitation, the event is automatically added to my calendar. I can only accept or decline by clicking on the event in the calendar.

I have tried to just send the invite, then what happens is that I get an email with an ics attachment.

What am I missing?

score 0 · Answer 1 · answered Apr 11 '17 at 23:34

0

You are creating a new calendar, that's why the calendar is added automatically. See the documentation https://github.com/ical4j/ical4j/wiki/Examples#Creating_a_new_calendar try the "Creating a meeting of four hour duration" and see if you still have a problem.

answered Apr 11 '17 at 23:34

Antoine

312
1
5
18

Now I create just an event and send it by email, but the outcome is the same, the event is automatically added to my calendar. It turns out you can change this behavior in gmail, so I set it to just add what I have accepted, but I still can see the invite, only if I hit "show original" I see the code of the invite. Still no pop-up or invitation shown in the email. – diminuta Apr 18 '17 at 09:10
@diminuta did you manage to solve the problem with gmail? I have s suspicion that google encourages to use their App Engine SDK for email markup (not free). https://developers.google.com/gmail/markup/reference/event-reservation – zkvarz Feb 27 '18 at 18:33

Send calendar invite per email with java

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