Instant Messaging with XMPP AKA Jabber

1
Instant Messaging with XMPP(AKA Jabber)
Jason Wambach 2005 Harpoon Technologies
2
Why use instant messaging?

• User Communication
• Application Monitoring
• Application Control
• Presence Notification

3
Why XMPP?

• Open Protocol
• Well Documented
• Extensible (Extensible Messaging and Presence
  Protocol)
• - See Jeps (Jabber enhancement Proposal) at
  www.jabber.org/jeps/
• IETF Standardized

4
Servers

• Commercial
• - Merak, Jabber XCP, Soapbox, Sun
• Free (fuhree?!)
• - Jive, Jabberd, OpenIM, Chime, etc.
• - GPL, BSD Licenses
• - Some available as dual license (Jive)
• Pre Existing
• - Google (talk.google.com)

5
Clients

• Many pre-existing GUI based clients
• Google Talk, Trillian Pro, Gaim, etc.
• APIs
• Smack (Java)
• Jabber-Net (C .Net)
• Jabber4R (Ruby)
• Jabber.py (Python)
• Others (C, Perl, Flash, etc)

6
Example using Smack
7
Client Connection
import org.jivesoftware.smack. XMPPConnection
con new XMPPConnection(host, port,
service) con.login(user, password)
-Will work through firewalls given a proxy route
and proper jvm settings -Usernames may or may not
contain host/resource information (ex.
user_at_host.com/resource) -Service is optional on
most servers (Not Google!) -port default is 5222
8
Sending Messages

• public void sendMessage(String user, String
  message) throws XMPPException
• Chat chat getChat(user)
• if (chat null)
• chat con.createChat(user)
• addChat(chat, user)
• chat.sendMessage(message)

-Using a map to keep track of Chats -Fire and
forget
9
Receiving Messages

• PacketFilter filter new PacketTypeFilter(Message
  .class)
• //Synchronous
• PacketCollector myCollector con.createPacketColl
  ector(filter)
• PacketListener myListener new PacketListener()
  
• public void processPacket(Packet packet)
• //do something
• //Asynchronus
• con.addPacketListener(myListener, filter)
• ...
• myCollector.pollResult() //check if any
  messages

-Allows Asynchronus (event driven) and
Synchronous access (Polling) -Filters set for
various packets -Many types of packets (Message,
Auth, Roster, Presence, etc)
10
Rosters

• public void addUserToRoster(String user) throws
  XMPPException
• if (!isUserOnRoster(user))
• Roster roster con.getRoster()
• if (roster ! null)
• roster.createEntry(user, user, null)
• public boolean isUserOnRoster(String user)
• Roster roster con.getRoster()
• if (roster ! null)
• return roster.contains(user)
• return false
• public boolean isUserOnline(String user)
• Roster roster con.getRoster()
• if (roster ! null roster.getPresence(user)
  ! null)
• return true

-Rosters and presence use permissions which must
be granted. (Auto or Manually). -Roster polling
not necessarily required to check presence, can
use roster listeners. -Presence is generally tied
to roster entries, although not required.
11
Server Setup

• Jive
• Easy setup on Linux/Windows
• Embedded or External Database (MySql)
• Web based Administration
• Google
• No need to setup anything to get started
• Latest Smack API has helper classes for google.

12
Considerations

• Not a silver bullet
• Not a replacement for a message queue system.
  (Guaranteed delivery, delivery notification, etc)
• Not all servers support every feature
• No server supports all features. (Voice, Server
  to Server connections, Querying, Clustering, etc)
• Some servers are more flexible than others
  (Integration with LDAP, etc)
• XML Overhead

13
Current XMPP Projects

• eBay notices
• Monitor auctions actively.
• Add/Remove custom auction searches.
• Not exactly within eBays use policy.
• Remote Appliance Monitoring
• Use javacomm to monitor aquarium heaters
• Notification of temp states/on-off, etc.
• Lighting Control
• Integrated with X10 to control home lighting/fans.

14
Questions?
15
Resources

• Jive Software - www.jivesoftware.org (Server,
  Smack API)
• Jabber Foundation - www.jabber.org
• Lists of Commercial and Open Source Servers
• Lists of Various APIs
• Lists of Various Clients
• JEP Listings
• XMPP Community Pages - www.xmpp.org
• Internet Engineering Task Force www.ietf.org
• RFC 3920 (XMPP Core)
• RFC 3921 (XMPP Messaging and Presence)
• Contact Me jwambach_at_harpoontech.com