Gaston Dombiak

Playing Casper in Openfire 3.5.0

Blog Post created by Gaston Dombiak Champion on Feb 19, 2008

The next major release of Openfire is going to be 3.5.0 and it will be released on March 6th. Daniel and I are very happy with this new release since it has lots of new features and improvements. Today I will explain how you can be connected but invisible to all or some users. This has been a very popular request in Openfire and in XMPP in general.

 

 

A few XMPP extensions were created for invisibility using different strategies (and may be goals). Some of them focused only in blocking your presence to other users while others were blocking incoming/outgoing presences, messages and IQ stanzas. But they have something in common that jeopardized their success. In a nutshell, they not only required server side changes but also client side changes thus making it hard for a user to find a server and a client that supports them.

 

As of Openfire 3.5.0 there is a very easy way to be invisible and at the same time be able to maintain a one-to-one chat, a group chat or appear visible to the users of your choice or gateways of your choice. The best part of it is that we are not relying on any XMPP extension but just using the XMPP RFC core.

 

Usually XMPP clients follow these steps while logging in:

  1. Connect to the XMPP server

  2. Secure the connection with TLS

  3. Authenticate with the server using SASL

  4. Send available presence to the server indicating that the client is now publicly available (e.g. <presence><priority>1</priority></presence>)

  5. Request their roster

 

The forth step is actually optional so if clients do not send an available presence then they will be connected to the server but will not appear available/online to other users. Unavailable users cannot get messages from other users unless they made available to them.

 

When the user decides to appear as online to someone in particular he can send an available presence to that user (e.g.

). Being available to a user means that the user will see you online and you can now chat with that user.

 

Users that are publicly unavailable can also join a room and have a groupchat. However, if the room is not anonymous (i.e. real JIDs are sent to room occupants) then the other users will know that you are connected and chatting. But probably you won't care about that unless you wanted to chat without anyone knowing that you are you.

 

Currently our Spark and Sparkweb clients are not able to join in invisible mode but implementing invisibility this way should be a lot less work for clients than implementing some XMPP extension.

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