DBus properties naming rules

Thiago Macieira thiago at kde.org
Wed Sep 9 10:06:26 PDT 2009

Em Quarta-feira 9. Setembro 2009, às 18.28.53, Simon McVittie escreveu:
> (I'm not sure why this thread wasn't on the D-Bus mailing list... see xdg
> archives for history.)
> On Tue, 08 Sep 2009 at 15:07:06 -0600, Aaron J. Seigo wrote:
> > we're talking about the allowed character set, not case or stylistic
> > format. it's a slightly different matter, as the former says which
> > characters are legal and the latter suggest how to use those characters.
> > (to state the obvious)
> Actually, I'd go a little further than that, and say that new D-Bus APIs
> SHOULD (but definitely not MUST) use capitalized words without punctuation
> (e.g. GetNameOwner) for D-Bus method, signal and property names.

Agreed. That's the D-Bus convention.

> This isn't a mandatory requirement for use of D-Bus, but it should be in
>  some list of "how to write a D-Bus API that does not violate
>  least-astonishment", along with common interoperability things like:
> * reply to each method call exactly once, with either a method reply or an
>   error
> * don't reply to things that are not method calls
> * don't send method replies or errors except as replies to method calls,
>   and don't send them to destinations other than the method call's sender

You'll note that most bindings don't allow these to happen either. And even in 
the low-level libdbus-1 API, you'll find out that you have to jump through 
hoops to get them.

> * don't implement more than one of (method, signal, property) with the same
>   name on the same interface
> * don't overload methods

These two are the same recommendation, from my point of view.

> * don't use varargs (which can't be represented in Introspect() output)

> * implement Introspectable on every object

High-level bindings will do that for you.

You should use a high-level binding. Really, you should. If you choose to use 
the low-level libdbus-1, note that Introspectable is not a very easy method to 
implement. If your object is part of a tree, you must also include the sub-
nodes in your introspection.

Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
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