[whatwg] Workers and addEventListener

To be absolutely clear (since there's some confusion about whether we are
talking about explicit MessagePorts, or about implicit ports for dedicated
workers).
Are you saying that this:

var channel = new MessageChannel();
channel.port1.postMessage("hi mom");
channel.port2.addEventListener("message", function(event)
{alert(event.data); }, false);

Should result in an alert dialog being fired? Because that does not match my
reading of the spec at all - the spec explicitly states that a port's
message queue is only enabled via start() or via setting the onmessage IDL
attribute.

I would not be opposed to changing the spec to include enabling a port's
message queue when addEventListener("message") is invoked.

-atw

On Wed, Oct 14, 2009 at 3:32 AM, Ian Hickson <ian at hixie.ch> wrote:

> On Tue, 29 Sep 2009, Zoltan Herczeg wrote:
> >
> > In WebKit implementation of MessagePort the addEventListener("message",
> > ...) does not enable the transmitting of messages. All messages are
> > actually discarded until a dummy function is assigned to onmessage.
>
> That is a bug. The port message queue is explicitly enabled during the
> creation of the dedicated worker (step 12).
>
>
> > And in the normative text, it is not mentioned that addEventListener
> > should also enable message transmitting.
>
> The normative text just says to fire an event; the DOM Events spec makes
> it clear that events can be handled using addEventListener()-added
> handlers.
>
>
> > Anyway, my qestion is:
> >   - should addEventListener enable message transmitting?
>
> Yes.
>
> >   - Should it do it in all cases, or only when "message" is passed as the
> > first argument
>
> It should only receive 'message' events if you say 'message' as the first
> argument.
>
> --
> Ian Hickson               U+1047E                )\._.,--....,'``.    fL
> http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
> Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
>
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Received on Thursday, 15 October 2009 10:54:23 UTC