DBUS service using glib: question

Thiago Macieira thiago.macieira at trolltech.com
Sun Jun 25 06:13:49 PDT 2006

Xavier Claessens wrote:
>I'm writing a simple dbus service using GLIB interface. My problem is
>that I have to keep some information about each client. For example how
>can I emit a signal on the object only for one specific client, or with
>different data for each client ?

You can't. A signal is emitted to whoever wants to listen to it.

If you want to talk to a specific destination, you should use a method 

>Another problem I have is how to know when a client connect/disconnect ?

Use the NameOwnerChanged signal from the org.freedesktop.DBus interface 
(object /, service org.freedesktop.DBus).

>Because I keep some data in a hash table, I want to know when a client
>disconnect to delete corresponding data.
>How can I make that properly with dbus ?!?

The NameOwnerChanged is emitted for the unique-connection-name when the 
client goes away. The new_owner string (the third string) will be empty.

> - I register a main object with a connect method which returns an ID to
>the client. The connect method also create and register a new object
>just for this client which is stored in a list. The client, using the ID
>can get the remote object and use it. Signals and method on this object
>will have special effects depending on what the client does with it and
>not interfering with what other clients does with other objects.
> - The main object has also a disconnect method which takes the ID in
>param and remove all data related to this client.
>Is that the good way ? Does someone knows if other projects does the
>same thing, like that I can see how they do...

Yes, that makes sense. In fact, this is what I recommend as a proper OOP 

Thiago José Macieira - thiago.macieira AT trolltech.com
Trolltech AS - Sandakerveien 116, NO-0402 Oslo, Norway
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