How to create and send update to existing event by

问题:

I'm using BiWeekly library to create VEVENT and then send it by using Java Mail API. Everything work fine but how can I create an update for an existing event, i.e. when I receive VEVENT which is update it won't create a new event in a calendar but will update an existing event?

I've tried to set sequence in the following way event.setSequence(2) , but it doesn't work. Upon receive email agent, Lotus Notes, google mail always creates new event.

This is my code of creating and sending event:

try {
            String from = "[e-mail]";
            String to = "[e-mail]";
            Properties prop = new Properties();
            prop.setProperty("mail.transport.protocol", "smtp");
            prop.setProperty("mail.host", "smtp.example.com");
            prop.setProperty("mail.user", "email");
            prop.setProperty("mail.password", "");

            Session session = Session.getDefaultInstance(prop, null);

            // Define message
            MimeMessage message = new MimeMessage(session);
            message.addHeaderLine("method=REQUEST");
            message.addHeaderLine("charset=UTF-8");
            message.addHeaderLine("component=VEVENT");

            message.setFrom(new InternetAddress(from));
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
            message.setSubject("Message Subject");

            StringBuffer sb = new StringBuffer();


            /*EVENT START*/
            VEvent event = new VEvent();
            event.setUid("ANATOLYTARNAVSKY123");
            event.setDescription("Invitation Description");
            event.setSummary("Invitation Description");
            event.setOrganizer("[e-mail]");
            event.setLocation("room");

            event.setSequence(sequence);


            Calendar start = Calendar.getInstance();
            start.add(Calendar.HOUR_OF_DAY, sequence + 2);
            Calendar end = Calendar.getInstance();
            end.add(Calendar.HOUR_OF_DAY, sequence + 2);

            event.setDateStart(start.getTime());
            event.setDateEnd(end.getTime());
            icals.addEvent(event);

            WriterChainText text = Biweekly.write(icals);
            String result = text.go(); 


            System.out.println(result);
            /*EVENT END*/

            StringBuffer buffer = sb.append(result);


            // Create the message part
            BodyPart messageBodyPart = new MimeBodyPart();

            // Fill the message
            messageBodyPart.setHeader("Content-Class", "urn:content-classes:calendarmessage");
            messageBodyPart.setHeader("Content-ID", "calendar_message");
            messageBodyPart.setDataHandler(new DataHandler( new ByteArrayDataSource(buffer.toString(), "text/calendar")));// very important

            // Create a Multipart
            Multipart multipart = new MimeMultipart();

            // Add part one
            multipart.addBodyPart(messageBodyPart);

            // Put parts in message
            message.setContent(multipart);

            // send message
            Transport.send(message);
        } catch (MessagingException me) {
            me.printStackTrace();
        } catch (Exception ex) {
            ex.printStackTrace();
        }

Here I'll place iterations of the code which I use to send the invitations:

• 2nd: Added LAST-MODIFIED property as advised by @Michael

Thank you in advance.

UPDATE 1:

This is first and second VEVENT as generated by my code and BiWeekly library:

CREATE EVENT- VEVENT DATA ONLY:

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Michael Angstadt//biweekly 0.4.3//EN
METHOD:REQUEST
BEGIN:VEVENT
DTSTAMP:20151113T100301Z
UID:ANATOLYTARNAVSKY123
DESCRIPTION:Invitation Description
SUMMARY:Invitation Description
ORGANIZER:mailto:[e-mail]
LOCATION:room
SEQUENCE:0
DTSTART:20151113T120301Z
DTEND:20151113T120301Z
END:VEVENT
END:VCALENDAR

UPDATE EVENT - VEVENT DATA ONLY:

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Michael Angstadt//biweekly 0.4.3//EN
METHOD:REQUEST
BEGIN:VEVENT
DTSTAMP:20151113T100333Z
UID:ANATOLYTARNAVSKY123
DESCRIPTION:Invitation Description
SUMMARY:Invitation Description
ORGANIZER:mailto:[e-mail]
LOCATION:room
SEQUENCE:1
DTSTART:20151113T130333Z
DTEND:20151113T130333Z
END:VEVENT
END:VCALENDAR

UPDATE 2:

When I send first and second invitation I get the following email on gmail:

The full original email content with removed tracerout path due to some privacy issues here:

CREATE EVENT - FULL EMAIL without routing part:

Date: Sat, 14 Nov 2015 08:03:47 -0700
From: [e-mail]
To: [e-mail]
Message-ID: *****
Subject: Escape Room Invitation
MIME-Version: 1.0
Content-Type: multipart/mixed; 
    boundary="----=_Part_0_451111351.1447513426727"
X-TM-AS-MML: disable
X-Content-Scanned: Fidelis XPS MAILER
x-cbid: 15111415-0021-0000-0000-000004CDC424

method=REQUEST
charset=UTF-8
component=VEVENT

------=_Part_0_451111351.1447513426727
Content-Type: text/calendar; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Class: urn:content-classes:calendarmessage
Content-ID: calendar_message

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Michael Angstadt//biweekly 0.4.3//EN
METHOD:REQUEST
CALSCALE:GREGORIAN
BEGIN:VEVENT
DTSTAMP:20151114T150346Z
UID:[e-mail]
STATUS:CONFIRMED
DESCRIPTION:Invitation Description
SUMMARY:Invitation Summary
ORGANIZER:mailto:[e-mail]
LOCATION:Escape room
TRANSP:OPAQUE
CREATED:20151114T150346Z
LAST-MODIFIED:20151114T150346Z
SEQUENCE:0
DTSTART:20151114T170346Z
DTEND:20151114T170346Z
END:VEVENT
END:VCALENDAR

------=_Part_0_451111351.1447513426727--

UPDATE EVENT - FULL EMAIL without routing part:

Date: Sat, 14 Nov 2015 08:05:06 -0700
From: [e-mail]
To: [e-mail]
Message-ID: *****
Subject: Escape Room Invitation
MIME-Version: 1.0
Content-Type: multipart/mixed; 
    boundary="----=_Part_0_451111351.1447513506015"
X-TM-AS-MML: disable
X-Content-Scanned: Fidelis XPS MAILER
x-cbid: 15111415-0029-0000-0000-000004D409DF

method=REQUEST
charset=UTF-8
component=VEVENT

------=_Part_0_451111351.1447513506015
Content-Type: text/calendar; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Class: urn:content-classes:calendarmessage
Content-ID: calendar_message

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Michael Angstadt//biweekly 0.4.3//EN
METHOD:REQUEST
CALSCALE:GREGORIAN
BEGIN:VEVENT
DTSTAMP:20151114T150505Z
UID:[e-mail]
STATUS:CONFIRMED
DESCRIPTION:Invitation Description
SUMMARY:Invitation Summary
ORGANIZER:mailto:[e-mail]
LOCATION:Escape room
TRANSP:OPAQUE
CREATED:20151114T150505Z
LAST-MODIFIED:20151114T150505Z
SEQUENCE:1
DTSTART:20151114T180505Z
DTEND:20151114T180505Z
END:VEVENT
END:VCALENDAR

------=_Part_0_451111351.1447513506015--

UPDATE 3 It looks that it works correctly on a Lotus Notes but Google Calendar still doesn't recognize an update event.

UPDATE 4 - SOLUTION

As @arnaudq wrote I've missed ATTENDEE property to make a Google Calendar to recognise update event. Here is an example how to do it:

        VEvent event = new VEvent();
        ...
        Attendee attendee = new Attendee("Anatoly Tarnavsky", "[e-mail]");
        attendee.setRsvp(true);
        attendee.setRole(Role.CHAIR);
        attendee.setParticipationStatus(ParticipationStatus.CONFIRMED);
        ...
        event.setProperty(attendee);

回答1:

Your code does not seem to explicitely set the UID property. As a consequence, the library probably generates a new one for you.

The UID property is what identifies this VEVENT amongst others. As a consequence, your update shall contain the same UID value as the original event that was sent earlier.

You are also missing at least one ATTENDEE property. One of the ATTENDEE should have its value set as a mailto uri corresponding to the gmail email address that is receiving the invite.

回答2:

Try adding a LAST-MODIFIED property to the VEVENT component. You seem to be doing everything else right--keeping the UID consistent and incrementing SEQUENCE.