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Re: What changes to Web Messaging spec are proposed? [Was: Re: Using ArrayBuffer as payload for binary data to/from Web Workers]

From: Kenneth Russell <kbr@google.com>
Date: Wed, 8 Jun 2011 14:24:24 -0700
Message-ID: <BANLkTikNA5mtF6WGFR2ZgkKHDgX34+5GqA@mail.gmail.com>
To: Arthur Barstow <art.barstow@nokia.com>
Cc: Andrew Wilson <atwilson@google.com>, Glenn Maynard <glenn@zewt.org>, Jonas Sicking <jonas@sicking.cc>, Dmitry Lomov <dslomov@google.com>, David Levin <levin@chromium.org>, ben turner <bent.mozilla@gmail.com>, "public-webapps@w3.org" <public-webapps@w3.org>, Ian Hickson <ian@hixie.ch>, Travis Leithead <Travis.Leithead@microsoft.com>
My understanding is that we have reached a proposal which respecifies
the "ports" argument to postMessage as an array of objects to
transfer, in such a way that we:

 - Maintain 100% backward compatibility
 - Enhance the ability to pass MessagePorts, so that the object graph
can refer to them as well
 - Allow more object types to participate in transfer of ownership in the future

To the best of my knowledge there are no active points of
disagreement. I think we are only waiting for general consensus from
all interested parties that this is the desired step to take.

If it is, I would be happy to draft proposed edits to the associated
specs; there are several, and the edits may be somewhat involved. I'd
also be happy to share the work with Ian or anyone else.

I don't know the various processes for web specs, but the Web
Messaging spec will definitely need to be updated if we decide to move
in this direction.

-Ken

On Wed, Jun 8, 2011 at 4:30 AM, Arthur Barstow <art.barstow@nokia.com> wrote:
> Now that the responses on this thread have slowed, I would appreciate if the
> participants would please summarize where they think we are on this issue,
> e.g. the points of agreement and disagreement, how to move forward, etc.
>
> Also, coming back to the question in the subject (and I apologize if my
> premature subject change caused any confusion or problems), since we have an
> open CfC (ends June 9 [1]) to publish a Candidate Recommendation of Web
> Messaging, is the Messaging spec going to need to change to address the
> issues raised in this thread?
>
> -Art Barstow
>
> [1] http://lists.w3.org/Archives/Public/public-webapps/2011AprJun/0797.html
>
> On Jun/3/2011 8:47 PM, ext Kenneth Russell wrote:
>>
>> On Fri, Jun 3, 2011 at 4:15 PM, Andrew Wilson<atwilson@google.com>  wrote:
>>>
>>> On Fri, Jun 3, 2011 at 3:23 PM, Glenn Maynard<glenn@zewt.org>  wrote:
>>>>
>>>> On Fri, Jun 3, 2011 at 5:15 PM, Andrew Wilson<atwilson@google.com>
>>>>  wrote:
>>>>>
>>>>> significant motivation. The stated motivations for breaking this API
>>>>> don't
>>>>> seem compelling to me given the existence of backwards-compatible
>>>>> alternatives.
>>>>
>>>> This proposal is backwards-compatible.  If the argument is an array,
>>>> nothing changes, so postMessage(..., [ports]) is equivalent to
>>>> postMessage(..., {ports: [ports]}).  (The array-only approach can be
>>>> done compatibly, too; the object version is just an alternative to
>>>> that.)  What's backwards-incompatible?
>>>
>>> Ah, I missed that piece (to be honest, I haven't been following this
>>> discussion in every detail - I only chimed in because of Jonas' request
>>> for
>>> implementation feedback).
>>>
>>>> For anyone not looking closely at the IDL while reading this, this
>>>> means deprecating (for whatever value "deprecate" has on the web) the
>>>> ports array in MessageEvent--not the ports parameter to postMessage
>>>> (that's a sequence).
>>>
>>> Does this affect the API for the SharedWorker onconnect message as well?
>>
>> Good point; that might inform not deprecating the ports array in
>> MessageEvent, but leaving it as is.
>>
>> -Ken
>>
>
Received on Wednesday, 8 June 2011 21:24:58 GMT

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