[Web-SIG] Web Site Process Bus
ianb at colorstudy.com
Mon Jun 25 23:48:34 CEST 2007
Jim Fulton wrote:
>> All 4 lines of it? ;)
>> subscribers = 
>> def notify(event):
>> for subscriber in subscribers:
>> Seriously, though, this handles the notification but not the state
>> machine, which I think is critical to the effort. It also doesn't
>> do any
>> error-handling for misbehaving subscribers, so not all subscribers are
>> guaranteed to run if there's an unhandled error in an earlier
>> subscriber. It also sends all events to all subscribers, instead of
>> partitioning the subscribers.
> Right. You need a dispatching layer behind this. The beauty of
> zope.event is that it puts very little requirement on people who
> publish events.
The problem is that it relies on some specific dispatching layer, and
that layer would *also* have to be defined to use this for something
useful like the start/stop events that are motivating this discussion.
That is, if you dispatch on "isinstance(event, tuple) and event and
event == 'some_name'", that's very different than "isinstance(event,
SomeClass)" or "implements(event, ISomething)" or whatever. Actual
servers have to emit something more specific than just "an object".
Ian Bicking | ianb at colorstudy.com | http://blog.ianbicking.org
| Write code, do good | http://topp.openplans.org/careers
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