[Phone Server dbus API]: sync vs. async / unsolicited or not

M. Dietrich mdt at emdete.de
Thu Jan 31 14:32:24 CET 2008


On Wed, Jan 30, 2008 at 07:48:08PM +0200, Nuutti Kotivuori wrote:
> I am a bit confused as to what is actually being asked here.

i have to apologize. i am probably the originator of this discussion
on the wrong view on dbus, because mickey and me startet it on irc.

i agree, that dbus is async by design for both, method calls and

the difference of signals and methods is that signals are broadcasted
and are initiated by the server. also they do not follow the
request/response paradigma.

the benefit of signals for us is that server can issue those without
beeing ask. the drawback is that dbus does not allow subscription to
signals and delivers signals to all clients (as mickey told me).

the point is that i didn't know how to handle request/response
decoupeled in glib and python because you don't see dbus's message
queue anymore. i did some research for python and found a hint here:


that it should be possible but is neither documented nor an example
exists. but

	from dbus.service import method                                  
	print method.__doc__

shows, how python supports it (see async_callbacks).

after all a client that would be interested in a special information
could also issue a method call (which is nothing else but sending a
request) and wake up to handle the response with the data. this would
be nearer at a signal subscription model.

are my assumptions correct so far?

best regards, 

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