I 'm developing a standalone Java test application using smack 4.3.4. I use In-Band for file transfers:
FileTransferManager fileTransferManager = FileTransferManager.getInstanceFor(connection);
FileTransferNegotiator.IBB_ONLY = true;
OutgoingFileTransfer fileTransfer = null;
try {
fileTransfer = fileTransferManager.createOutgoingFileTransfer(JidCreate.entityFullFrom(buddyJID + "/Spark"));
} catch (XmppStringprepException ex) {
LOG.log(Level.SEVERE, null, ex);
}
if (fileTransfer != null) {
OutgoingFileTransfer.setResponseTimeout(500);
...
try {
fileTransfer.sendFile(file, "sending attachment...");
} catch (SmackException ex) {
LOG.log(Level.SEVERE, null, ex);
}
...
I monitor the file transfer and it is sent correctly.
INFO: Initializing connection to server localhost port 5222 [Wed Apr 29 15:36:25 CEST 2020]
INFO: Connected: true [Wed Apr 29 15:36:45 CEST 2020]
INFO: user001 authenticated? true [Wed Apr 29 15:36:46 CEST 2020]
...
INFO: Sending attachment 'test.txt' to user user002#localhost [Wed Apr 29 15:36:55 CEST 2020]
INFO: status is:Initial [Wed Apr 29 15:36:55 CEST 2020]
INFO: status is:Initial [Wed Apr 29 15:36:55 CEST 2020]
INFO: File transfer status: Negotiating Transfer, progress: 0.0 [Wed Apr 29 15:36:55 CEST 2020]
INFO: test.txt has been successfully transferred. [Wed Apr 29 15:36:56 CEST 2020]
INFO: The file transfer is done. [Wed Apr 29 15:36:56 CEST 2020]
INFO: Attachment test.txt sent from user001#localhost to user002#localhost [Wed Apr 29 15:36:56 CEST 2020]
When my user(s) connect and login to Openfire, even before the start sending attachments, I add a listener to listen to file transfers:
final FileTransferManager manager = FileTransferManager.getInstanceFor(connection);
// FileTransferNegotiator.setServiceEnabled(connection, true);
manager.addFileTransferListener((FileTransferRequest request) -> {
// Check to see if the request should be accepted
if (request.getFileName() != null) {
try {
// Accept it
IncomingFileTransfer transfer = request.accept();
// monitorFileTransfer(transfer, "");
try (InputStream fileReceived = transfer.receiveFile();
BufferedInputStream bis = new BufferedInputStream(fileReceived)) {
...
} else {
try {
// Reject it
request.reject();
LOG.warning("File rejected " + request.getFileName());
} catch (SmackException.NotConnectedException | InterruptedException ex) {
LOG.log(Level.SEVERE, null, ex);
}
}
However, the listener is never called. Do I need to add the listener at a specific moment? Is there something else I 've been missing? The results is that the file transfers are being sent to Openfire and are never consumed.
Last stanzas:
<iq xmlns="jabber:client" to="user001#localhost/aktuu2n806" from="localhost" id="679-1085" type="get">
<query xmlns="jabber:iq:version"/>
</iq>
<iq xmlns="jabber:client" to="localhost" id="679-1085" type="error">
<error xmlns="jabber:client" type="modify">
<not-acceptable xmlns="urn:ietf:params:xml:ns:xmpp-stanzas"/>
</error>
</iq>
My code is based on the documentation example. Do I need to configure something else? Since they are transferred as in-band I shouldn't.
Thank you in advance for your prompt reply.
The file transfer was not actually happening this is why the listener was listening but wa receiving nothing.
To send a file you need the full JID of the recipient. If you use smack, there is no physical XMPP client (like spark). In that case you use “Smack” or “Resource” (see here).
fileTransfer = fileTransferManager.createOutgoingFileTransfer(JidCreate.entityFullFrom(buddyJID + "/Smack")));
However, I still get an error:
XMPP error reply received from user002#localhost/Smack: XMPPError: not-allowed - cancel
and the file is not sent.
UPDATE: And of course the problem had nothing to do with smack. The issue was that the tool I have created was reading and writing to the same file, as a result, the file was erased and the error was because smack was requested to transfer an empty file. So, if you see this error, check the file you try to transfer first; it might have 0 bytes.
Related
I am working on a tool which uses ews-java-api to create, update and delete calendar items in Outlook agenda. It has been working fine, but now sometimes when it tries to update some calendar item, I get following error:
microsoft.exchange.webservices.data.core.exception.service.remote.ServiceResponseException: At least one recipient isn't valid., A message can't be sent because it contains no recipients.
at microsoft.exchange.webservices.data.core.response.ServiceResponse.internalThrowIfNecessary(ServiceResponse.java:278)
at microsoft.exchange.webservices.data.core.response.ServiceResponse.throwIfNecessary(ServiceResponse.java:267)
at microsoft.exchange.webservices.data.core.request.MultiResponseServiceRequest.execute(MultiResponseServiceRequest.java:165)
at microsoft.exchange.webservices.data.core.ExchangeService.internalUpdateItems(ExchangeService.java:691)
at microsoft.exchange.webservices.data.core.ExchangeService.updateItem(ExchangeService.java:762)
at microsoft.exchange.webservices.data.core.service.item.Item.internalUpdate(Item.java:279)
at microsoft.exchange.webservices.data.core.service.item.Item.update(Item.java:400)
at be.vrt.quintiqexchange.main.QuintiqAdapter.insertUpdateCalendarItems(QuintiqAdapter.java:879)
at be.vrt.quintiqexchange.main.QuintiqAdapter.updateCalendarItems(QuintiqAdapter.java:796)
at be.vrt.quintiqexchange.main.QuintiqAdapter.run(QuintiqAdapter.java:286)
at java.lang.Thread.run(Thread.java:745)
Recently all the exchange accounts have been migrated from local Outlook servers to Office365 cloud servers. Maybe this has something to do with it? Or anybody have any idea on what is going wrong?
Following code is to perform the update for an item:
Item it = alitems.get(i);
...
it.update(ConflictResolutionMode.AlwaysOverwrite);
Following is the url being used to access office365 ews:
exchangewebservice = https://outlook.office365.com/EWS/Exchange.asmx
Thanks in advance
Edit: I use ews-java-api version 2.0
Edit: Here you can see that the error occurs on one line and than the next line, with the same recipient it doesn't occur...
microsoft.exchange.webservices.data.core.exception.service.remote.ServiceResponseException: At least one recipient isn't valid., A message can't be sent because it contains no recipients.
at microsoft.exchange.webservices.data.core.response.ServiceResponse.internalThrowIfNecessary(ServiceResponse.java:278)
at microsoft.exchange.webservices.data.core.response.ServiceResponse.throwIfNecessary(ServiceResponse.java:267)
at microsoft.exchange.webservices.data.core.request.MultiResponseServiceRequest.execute(MultiResponseServiceRequest.java:165)
at microsoft.exchange.webservices.data.core.ExchangeService.internalUpdateItems(ExchangeService.java:691)
at microsoft.exchange.webservices.data.core.ExchangeService.updateItem(ExchangeService.java:762)
at microsoft.exchange.webservices.data.core.service.item.Item.internalUpdate(Item.java:279)
at microsoft.exchange.webservices.data.core.service.item.Item.update(Item.java:400)
at be.vrt.quintiqexchange.main.QuintiqAdapter.insertUpdateCalendarItems(QuintiqAdapter.java:880)
at be.vrt.quintiqexchange.main.QuintiqAdapter.updateCalendarItems(QuintiqAdapter.java:703)
at be.vrt.quintiqexchange.main.QuintiqAdapter.run(QuintiqAdapter.java:283)
at java.lang.Thread.run(Thread.java:745)
WARN be.vrt.quintiqexchange.main.QuintiqAdapter - At least one recipient isn't valid., A message can't be sent because it contains no recipients.by UPDATE for subject: on Thu Jun 23 14:00:00 CEST 2016 Thu Jun 23 19:00:00 CEST 2016 of user name.lastname#domain.com
INFO be.vrt.quintiqexchange.main.QuintiqAdapter - Appointment updated for subject: NIET DAG on Fri Aug 05 10:00:00 CEST 2016 Fri Aug 05 18:00:00 CEST 2016 of user name.lastname#domain.com
INFO be.vrt.quintiqexchange.main.QuintiqAdapter - Appointment updated for subject: PROEF st5 on Mon Aug 22 10:00:00 CEST 2016 Mon Aug 22 20:30:00 CEST 2016 of user name.lastname#domain.com
This means that the recipient isn't really the issue, I guess...
p.s. I replaced the original mailaddress but believe me, it's a correct mailadres :)
In my case, if the address is not properly trimmed and has any whitespace characters at all, EWS vomits this exception up.
I have written a JAXMPPClient.java program which uses tigase.jaxmpp.j2se.Jaxmpp 3.0.0
I have the following .jar files in my build path
jaxmpp-core-3.0.0
jaxmpp-j2se-3.0.0
and folder jaxmpp-all-3.0.0 containing many .jar files. The JAXMPPClient.java is as follows
Jaxmpp conn = new Jaxmpp();
conn.getConnectionConfiguration().setConnectionType(
ConnectionType.socket);
conn.getConnectionConfiguration().setDomain(IP_ADDRESS_OF_XMPP_SERVER);
conn.getConnectionConfiguration().setPort(PORT_NUMBER_OF_XMPP_SERVER);
conn.getConnectionConfiguration().setUserJID(FROM_USERID + "#" +
IP_ADDRESS_OF_XMPP_SERVER);
conn.getConnectionConfiguration().setUserPassword(FROM_PASSWORD);
String s = tigase.jaxmpp.j2se.connectors.socket.
SocketConnector.HOSTNAME_VERIFIER_DISABLED_KEY
conn.getSessionObject().setProperty(s, Boolean.TRUE);
try {
System.out.println("Before login");
conn.login();
System.out.println("After login");
} catch (final JaxmppException e) {
e.printStackTrace();
}
I am getting
Before login
Sep 29, 2015 5:17:12 PM tigase.jaxmpp.j2se.Jaxmpp createConnector
INFO: Using SocketConnector
Sep 29, 2015 5:17:12 PM tigase.jaxmpp.j2se.connectors.socket.SocketConnector start
INFO: Resolving SRV recrd of domain '123.45.678.910'
Sep 29, 2015 5:17:12 PM tigase.jaxmpp.j2se.connectors.socket.SocketConnector start
INFO: Opening connection to /123.45.678.910:5222
Sep 29, 2015 5:17:12 PM tigase.jaxmpp.j2se.connectors.socket.Worker run
WARNING: Exception in worker
java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:209)
at java.net.SocketInputStream.read(SocketInputStream.java:141)
at tigase.jaxmpp.j2se.connectors.socket.TextStreamReader.read(TextStreamReader.java:49)
at tigase.jaxmpp.j2se.connectors.socket.Worker.run(Worker.java:99)
After login
The IP Address, Port number, From JabberID and Password are correct and are working fine from iOS and Android Apps. Also I am able to successfully ping the Tigase server IP address.
From where is the java.net.SocketException being thrown ? How can I fix this problem ?
I'd like to use Oracle Advanced queue via JMS.
I've create queue table and queue via plsql like this:
BEGIN
DBMS_AQADM.CREATE_QUEUE_TABLE(
queue_table => 'QT3',
queue_payload_type => 'RAW');
END;
/
BEGIN
DBMS_AQADM.CREATE_QUEUE(
queue_name => 'Q3',
queue_table => 'QT3');
END;
/
Then I try to send a message like this:
System.setProperty("oracle.jms.traceLevel", "6");
ConnectionFactory connectionFactory = AQjmsFactory.getConnectionFactory("x.x.x.x", "xxx", 1521, "thin");
Connection connection = connectionFactory.createConnection("xxx", "xxx");
connection.start();
Session session = connection.createSession(true, 0);
Queue queue = session.createQueue("Q3");
MessageProducer producer = session.createProducer(queue);
TextMessage message = session.createTextMessage("valami");
message.setJMSType("text");
producer.send(message);
session.commit();
The above code finds the queue (If I replace Q3 to something else then it says queue not found, so I guess that basic connection setup is OK), but I got NPE exception at producer.send. I set aqapi trace and I got this output:
main [Fri Jun 20 14:22:51 CEST 2014] AQjmsProducer.send-1: entry
main [Fri Jun 20 14:22:51 CEST 2014] AQjmsProducer.send-main: entry
main [Fri Jun 20 14:22:51 CEST 2014] AQjmsProducer.send: queue: RISKOPALL.Q3
main [Fri Jun 20 14:22:51 CEST 2014] AQjmsProducer.send: dest_queue: RISKOPALL.Q3
main [Fri Jun 20 14:22:51 CEST 2014] AQjmsProducer.jdbcEnqueue: entry
main [Fri Jun 20 14:22:51 CEST 2014] AQjmsProducer.checkMessageType: adt type: null
main [Fri Jun 20 14:22:51 CEST 2014] AQjmsProducer.checkMessageType: message_class: oracle.jms.AQjmsTextMessage
main [Fri Jun 20 14:22:51 CEST 2014] AQjmsProducer.jdbcEnqueue: exit
Exception in thread "main" java.lang.NullPointerException
at oracle.jms.AQjmsProducer.checkMessageType(AQjmsProducer.java:2362)
at oracle.jms.AQjmsProducer.jdbcEnqueue(AQjmsProducer.java:823)
at oracle.jms.AQjmsProducer.send(AQjmsProducer.java:747)
at oracle.jms.AQjmsProducer.send(AQjmsProducer.java:517)
at aqjms.AqJmsTest.main(AqJmsTest.java:55)
I decompiled aqapi.jar and found that the NPE is thrown because "adtType" parameter is null at AQjmsProducer.checkMessageType.
What is this ADT type and How shall I set it correctly?
Thank you very much!
Setting the payload type of the queue solved the problem:
BEGIN
DBMS_AQADM.CREATE_QUEUE_TABLE(
queue_table => 'QT3',
queue_payload_type => 'SYS.AQ$_JMS_TEXT_MESSAGE',
compatible => '8.1.0');
END;
/
I want to connect to a FTP Server, in this case FileZilla Server, with Java. I've download edtFTPJ/free and I've been trying the examples that they sent in that package. Connecting to the server, deleting folder/files, renaming, creating folders works, but when I want to get the directory list, the connection gets closed. (This also happens with another library called FTP4J.) Here is the code:
package ftp_classes;
import com.enterprisedt.net.ftp.FileTransferClient;
import com.enterprisedt.net.ftp.FTPFile;
import com.enterprisedt.util.debug.Level;
import com.enterprisedt.util.debug.Logger;
public class GetDirectoryListing {
public static void main(String[] args) {
String host = "localhost";
String username = "user";
String password = "password";
// set up logger so that we get some output
Logger log = Logger.getLogger(GetDirectoryListing.class);
Logger.setLevel(Level.INFO);
FileTransferClient ftp = null;
try {
com.enterprisedt.util.debug.Logger.setLevel(com.enterprisedt.util.debug.Level.DEBUG);
// create client
log.info("Creating FTP client");
ftp = new FileTransferClient();
// set remote host
log.info("Setting remote host");
ftp.setRemoteHost(host);
ftp.setUserName(username);
ftp.setPassword(password);
// connect to the server
log.info("Connecting to server " + host);
ftp.connect();
log.info("Connected and logged in to server " + host);
log.info("Getting current directory listing");
FTPFile[] files = ftp.directoryList(".");
for (int i = 0; i < files.length; i++) {
log.info(files[i].toString());
}
// Shut down client
log.info("Quitting client");
ftp.disconnect();
log.info("Example complete");
} catch (Exception e) {
e.printStackTrace();
}
}
}
here is the console output:
INFO [ftp_classes.GetDirectoryListing] 1 Jun 2012 14:05:00.151 : Setting remote host
INFO [ftp_classes.GetDirectoryListing] 1 Jun 2012 14:05:00.151 : Connecting to server localhost
DEBUG [FileTransferClient] 1 Jun 2012 14:05:00.151 : Configured client
DEBUG [FTPClient] 1 Jun 2012 14:05:00.159 : Connecting to localhost/127.0.0.1:21
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.175 : 220-FileZilla Server version 0.9.41 beta
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.175 : 220-written by Tim Kosse (Tim.Kosse#gmx.de)
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.177 : 220 Please visit http://sourceforge.net/projects/filezilla/
DEBUG [FileTransferClient] 1 Jun 2012 14:05:00.179 : Client connected
DEBUG [FileTransferClient] 1 Jun 2012 14:05:00.180 : Logging in
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.180 : ---> USER user
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.180 : 331 Password required for user
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.181 : ---> PASS ********
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.181 : 230 Logged on
DEBUG [FileTransferClient] 1 Jun 2012 14:05:00.181 : Logged in
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.181 : ---> TYPE I
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.182 : 200 Type set to I
INFO [ftp_classes.GetDirectoryListing] 1 Jun 2012 14:05:00.182 : Connected and logged in to server localhost
INFO [ftp_classes.GetDirectoryListing] 1 Jun 2012 14:05:00.182 : Getting current directory listing
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.189 : ---> SYST
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.189 : 215 UNIX emulated by FileZilla
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.194 : ---> PWD
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.194 : 257 "/" is current directory.
DEBUG [FTPClient] 1 Jun 2012 14:05:00.194 : setupDirDetails(.) returning: /
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.195 : ListenOnAllInterfaces=true
com.enterprisedt.net.ftp.ControlChannelIOException: Software caused connection abort: socket write error
at com.enterprisedt.net.ftp.FTPControlSocket.writeCommand(FTPControlSocket.java:1020)
at com.enterprisedt.net.ftp.FTPControlSocket.sendCommand(FTPControlSocket.java:997)
at com.enterprisedt.net.ftp.FTPControlSocket.setDataPort(FTPControlSocket.java:813)
at com.enterprisedt.net.ftp.FTPControlSocket.sendPORTCommand(FTPControlSocket.java:669)
at com.enterprisedt.net.ftp.FTPControlSocket.createDataSocketActive(FTPControlSocket.java:616)
at com.enterprisedt.net.ftp.FTPControlSocket.createDataSocket(FTPControlSocket.java:583)
at com.enterprisedt.net.ftp.FTPClient.setupDataSocket(FTPClient.java:2648)
at com.enterprisedt.net.ftp.FTPClient.dir(FTPClient.java:3664)
at com.enterprisedt.net.ftp.FTPClient.dir(FTPClient.java:3756)
at com.enterprisedt.net.ftp.FTPClient.dirDetails(FTPClient.java:3583)
at com.enterprisedt.net.ftp.FileTransferClient.directoryList(FileTransferClient.java:647)
at ftp_classes.GetDirectoryListing.main(GetDirectoryListing.java:52)
DEBUG [FTPControlSocket] 1 Jun 2012 14:05:00.197 : ---> PORT 127,0,0,1,201,168
Can anyone help me? I really don't know why this is happening.
The error is happening when the client tries to open a listening socket for the server to connect to and send the directory listing. I'm not sure why that would happen, but I do recommend changing the connection-mode from 'active' to 'passive', which may bypass the problem. You can do that as follows:
ftp.getAdvancedFTPSettings().setConnectMode(FTPConnectMode.PASV);
i want to send iCalendar meeting invitations. I am using Google App engine, Java.
I managed to send a mail with an iCalendar file as an attachment, but programs like Outlook do not automatically recognize it as a meeting invitation.
I figure, i have to set the content-type of the attachment to: "text/calendar; method=REQUEST", but it seems to me, GAE is not accepting this?
Update: I was wrong above. I actually found, that i have to send the mail with the iCalendar part directly in the content, not as an attachment! So my problem is, GAE seems not to accept setting the content-type of the message itself.
Has anyone succesfully send a meeting invitation iCalendar element through mail using GAE?
Update:
I understand, i have to be more specific. In fact, i want to send iMip messages. iMip messages are not multipart, their content-type is "text/calendar". And in the case of sending a meeting invitation, it would be "text/calendar;method=REQUEST". So i tried this:
Message msg = new MimeMessage(session);
msg.setContent(iCalendarAsString, "text/calendar;method=REQUEST");
Then i send the message with Transport.send(..);
In the logs in the development server of GAE i then see, that the content type is "text/plain".
that's why i said, i think, GAE is not accepting setting a different content type.
Or am i wrong?
Update 2
OK, here's the complete code:
Properties props = new Properties();
Session session = Session.getDefaultInstance(props, null);
try {
Message msg = new MimeMessage(session);
msg.setFrom(new InternetAddress("ical#someapp.appspotmail.com", "SomeApp"));
msg.addRecipient(Message.RecipientType.TO,
new InternetAddress("me#mydomain.de", "Sven Busse"));
msg.setSubject("meeting invitation!");
msg.setContent(iCalendarAsString, "text/calendar;method=REQUEST");
Transport.send(msg);
} catch (AddressException e) {
log.warning(e.toString());
e.printStackTrace();
} catch (MessagingException e) {
log.warning(e.toString());
e.printStackTrace();
} catch (UnsupportedEncodingException e) {
log.warning(e.toString());
e.printStackTrace();
}
So, i set the content-type to "text/calendar;method=REQUEST". And once i send, this is the logs:
14.09.2011 09:52:59 com.google.appengine.api.mail.dev.LocalMailService log
INFO: MailService.send
INFO: From: SomeApp <ical#someapp.appspotmail.com>
INFO: To: Sven Busse <me#mydomain.de>
INFO: Reply-to: SomeApp <ical#someapp.appspotmail.com>
INFO: Subject: meeting invitation!
INFO: Body:
INFO: Content-type: text/plain
INFO: Data length: 458
So, the logs don't look pretty, but you can see, the content-type has changed to "text/plain".
Update 3:
Delivered-To: me#mydomain.de
Received: by 10.68.59.7 with SMTP id v7cs112540pbq;
Thu, 15 Sep 2011 07:45:55 -0700 (PDT)
Received: by 10.52.95.44 with SMTP id dh12mr1121151vdb.20.1316097954738;
Thu, 15 Sep 2011 07:45:54 -0700 (PDT)
Return-Path: <3oQ9yTgoJCgIdqqmngvqpciockn.eqouxgp.dwuugiqqingockn.eqo#2uix4h7xygsz66weerlq.apphosting.bounces.google.com>
Received: from mail-vw0-f69.google.com (mail-vw0-f69.google.com [209.85.212.69])
by mx.google.com with ESMTPS id o9si1579035vcv.136.2011.09.15.07.45.53
(version=TLSv1/SSLv3 cipher=OTHER);
Thu, 15 Sep 2011 07:45:53 -0700 (PDT)
Received-SPF: pass (google.com: domain of 3oQ9yTgoJCgIdqqmngvqpciockn.eqouxgp.dwuugiqqingockn.eqo#2uix4h7xygsz66weerlq.apphosting.bounces.google.com designates 209.85.212.69 as permitted sender) client-ip=209.85.212.69;
Authentication-Results: mx.google.com; spf=pass (google.com: domain of 3oQ9yTgoJCgIdqqmngvqpciockn.eqouxgp.dwuugiqqingockn.eqo#2uix4h7xygsz66weerlq.apphosting.bounces.google.com designates 209.85.212.69 as permitted sender) smtp.mail=3oQ9yTgoJCgIdqqmngvqpciockn.eqouxgp.dwuugiqqingockn.eqo#2uix4h7xygsz66weerlq.apphosting.bounces.google.com
Received: by vws20 with SMTP id 20so3831617vws.4
for <me#mydomain.de>; Thu, 15 Sep 2011 07:45:53 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.236.187.1 with SMTP id x1mr5481998yhm.8.1316097953249; Thu, 15
Sep 2011 07:45:53 -0700 (PDT)
Reply-To: SomeApp <ical#someapp.appspotmail.com>
X-Google-Appengine-App-Id: someapp
Message-ID: <20cf305e2551fe38a104acfbee28#google.com>
Date: Thu, 15 Sep 2011 14:45:53 +0000
Subject: meeting invitation!
From: SomeApp <ical#someapp.appspotmail.com>
To: Sven Busse <me#mydomain.de>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed; delsp=yes
BEGIN:VCALENDAR
PRODID:-//Ben Fortuna//iCal4j 1.0//EN
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:REQUEST
BEGIN:VEVENT
DTSTAMP:20110915T144552Z
UID:20110915T144552Z-1#someapp.appspotmail.com
SUMMARY:tolles projekt\, macht viel spass.
DTSTART;VALUE=DATE:20110919
DTEND;VALUE=DATE:20110926
DESCRIPTION:tolles projekt\, macht viel spass.
ATTENDEE;ROLE=REQ-PARTICIPANT;RSVP=TRUE:mailto:me#mydomain.de
ORGANIZER:mailto:ical#someapp.appspotmail.com
END:VEVENT
END:VCALENDAR
Maybe you should think of using a service like http://context.io/ ?
(not affiliated !)