Deferred framework is probably more like BOOST::ASIO. With callbacks,
your adding code to be executed in a "reactor" thread ( ie. the thread
from which reactor.run() is called ). This way you can shoot of a
separate thread ( say with deferToThread ) to do some work, queue up
some callbacks then "fire" the callbacks in the reactor thread.
node_clicked is probably expected to return a deferred. If you have the
return value already, you can return defer.succeed or defer.fail. Read
the twisted docs about Generating Deferreds etc.
On Tue, 2009-02-03 at 22:37 +0100, Kristian Lippert wrote:
> Hi
> I have a play-method in my own stream-player and it works:
>
> def node_clicked(self, widget, item):
> def play_uri(self, station):
> # We already know the real URL of the playable audio
> stream, no
> # need to query the resource manager
> # get player and start playing
> player =
> self.frontend.retrieve_controllers('/poblesec/music_player')[0]
> player.player.play_model(station)
> main = self.frontend.retrieve_controllers('/poblesec')[0]
> main.show_music_player()
> self.stop_loading_animation()
>
> pdb.set_trace()
> if isinstance(item, Action):
> item.run()
> elif isinstance(item, PlayableModel):
> play_uri(self, item)
>
> It works fine but if there are problems with the stream it will hang
> for a while, so I thought I could use a deferred, like:
>
> def node_clicked(self, widget, item):
>
> def play_uri(self, station):
> # We already know the real URL of the playable audio
> stream, no
> # need to query the resource manager
> # get player and start playing
> player =
> self.frontend.retrieve_controllers('/poblesec/music_player')[0]
> player.player.play_model(station)
>
> main = self.frontend.retrieve_controllers('/poblesec')[0]
> main.show_music_player()
> self.stop_loading_animation()
>
> pdb.set_trace()
> if isinstance(item, Action):
> item.run()
> elif isinstance(item, PlayableModel):
> dfr = defer.Deferred().addCallback(play_uri)
> return dfr(self, item)
>
> My problem is that I am not sure:
> 1) Do I create the deferred in the right manner?
> 2) How does the binding of the parameters happen?
> 3) Do I need to activate the deferred my self or will this happen by
> magic by it self?
>
> As far as I can read the deferred can be compared to the .NET
> asynchronous delegates or boost::thread. Boost::thread is much simpler
> but they share the problem regarding binding variables.
>
> Please help me fix the code!
>
> Best Regards,
> Kristian
>
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