Re: [hybi] Informal survey: "Non Request-Response Communication over the Web, and What's Missing"

Thanks for the comments, Joakim.

On Fri, Jan 16, 2015 at 9:49 PM, Joakim Erdfelt <joakim@intalio.com> wrote:

> Some commentary ...
>
> Be careful with "reliable data delivery".
> This has many different meanings to different people.
>
> Bayeux and Cometd (for example) have acknowledgement extensions
> specifically for unreliable data networks (mobile) that allow the server or
> client to know if the opposite side has received the complete message or
> not.
>
> This level of reliable message delivery could probably exist as a
> WebSocket extension. a message-ack extension with exposure at the various
> WebSocket APIs.
>
>
Good point. We cut the details but it might have just led to confusion.
I'll fix it.

> WebSocket Gaps:
>
> 1. Half-Closed
>
> half-closed connections are currently supported by the WebSocket protocol
> spec.
> and many existing implementations do it correctly today (thanks autobahn!)
> several libraries already rely on this behavior (bayeux, cometd)
>

Right. It's missing on the WebSocket API.

>
> however, other layers, apis, and non-websocket bugs can cause problems
> here.
> eg: its impossible with Android 5.x to do half-closed via SSL, on any
> protocol, mostly due to many horrid bugs in their SSLEngine.
>
> 2. Flow-Control
>
> For standard http/1.1 (not http/2) this is handled at the tcp/ip level.
> For http/2 this is handled by its flow-control parts of that spec.
> What else do you mean here?
> Is this section about how to expose this on the Javascript WebSocket API?
>
>
Yes. Flow control is not exposed to the API level. A script cannot pose any
backpressure on a WebSocket without blocking the main thread.

> 3. Message-level metadata
>
> Let this be part of an application specific protocol layer, or an
> extension handling it (with Javascript WebSocket API changes to expose
> extension manipulation. see below)
> Note: This is quite a passionate topic on the ietf-http-wg mailing list
> also, with more people against it than for it.
>
> 4. Keep-Alive
>
> Most existing applications are happy with a combination of tcp/ip
> keep-alive and websocket ping/pong so far.
> With http/2 there's other keep-alive strategies.
> Is is really a WebSocket protocol gap?
> Or just another Javascript WebSocket API gap?
>

Yes. It's about the API. Sorry that it's unclear.

>
> 5. Multiplexing and session priority
>
> One concern with the common response: WebSocket over HTTP/2 will address
> this.
> It seems that the folks running the http2 spec track (ietf-http-wg) have
> punted and want hybi to define it, and the folks here at hybi seem to think
> that the ietf-http-wg folks will define it.  Have there been some
> discussion between these 2 groups yet? (even offline / face to face?)
>
>
No decision is made officially yet, I think.

> The Layering Concern:
>
> Don't forget, the websocket extensions are a layer too.
>
>
Yes!

> Other thoughts:
>
> If this is an effort to get baseline of effort for the Javascript
> WebSocket in the browser, then you also have the following often asked
> questions ...
>
> * Handling authentication / authorization credentials.  submitting them,
> and getting reasonable error messages out of the API for when problems
> occur.
> * Controlling extensions, both at the initial handshake, and ongoing in
> the write/send apis (think compress / dont compress flags as a real world
> usecase for today)
> * Better error messages when use of the API results in failure to
> open/connect due to violation of WebSocket spec rules
>
>
Thanks for the list. Yeah, there're lots of overdue things.

The doc is not only for WebSocket API refinement. More general discussion
about what's the best messaging API/protocol we should build for better web
ecosystem.

>
>
> --
> Joakim Erdfelt <joakim@intalio.com>
> webtide.com <http://www.webtide.com/> - intalio.com/jetty
> Expert advice, services and support from from the Jetty & CometD experts
> eclipse.org/jetty - cometd.org
>
> On Fri, Jan 16, 2015 at 1:42 AM, Takeshi Yoshino <tyoshino@google.com>
> wrote:
>
>> Hi all,
>>
>> I and Wenbo did an informal survey of protocol gaps. We hope this would
>> help moving forward the discussions about protocol/API design to some
>> extent.
>>
>>
>> https://github.com/bidiweb/bidiweb-semantics/blob/master/SurveyOfProtocolGaps.md
>>
>>
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>>
>>
>