Re: Re: Query / Response type messages

[Stuart Booth]

On Thu, 1 Jan 2004 18:15:13 -0000, "Kevin Hawkins"
<<a
href="/group/xAP_developer/post?postID=787AE0DSTezs7TTTpgKlBgssxlZALnWRqH2RqLEA8UwJRXdzRZBr06bhTj04jUw_RH9zBpzYkcHwdCadEipOQ6k6">lists@u...</a>>
wrote:

> > On Thu, 01 Jan 2004 16:46:40 -0000, "Edward Pearson"
> > <<a
href="/group/xAP_developer/post?postID=RP738jN6L3HyYTpz4_gUeWZBLsRHr7i9kvQ0q-maynxeL4ZyTv2zLQ9HNV6qU7s0X_A6oemtuhCP3Q2ftQFHhQ22j1uW1Xivxw">edward.mailgroup@b...</a>>
wrote:
> >
> > >I think the xAPstatus.response should be targetted at the
> > sender of the
> > >xAPstatus.request.
> >
> > Now there's an interesting idea I hadn't thought of
> > before. I think I shall update my various applications to
> > do that as I like that.

>I am interested in what you feel the benefit is here - except obviously
the
>originator knows that the device responded directly to this request.

That's what appeals to me. Somebody has requested some information.
Untargetted responses are vague. If there were 2 slightly different
information requests sent at roughly the same time, which is the
response that I want? I have to inspect the query, hopefully embedded
within the response block and compare it to what I had asked, which I
now have to keep around.

>There was some thought went into this original non targeted response
when I
>suggested it. Given that the device is reporting current status then
all
>devices are interested in this info, not just the one that originated
the
>request.

That information is still available to anybody else, and with the
addition of the original query within the reply block anybody else has
all the information they want.

> Some devices may filter incoming packets based on 'target' and
>could therefore drop the response.

Filtering out targetted messages, and listening only to general
untargated broadcasts, or those targetted at them?

> If targeting was used then listeners
>interested in status would have to receive and parse ALL xAP messages
(even
>ones not targeted at themselves) to inspect the schema before knowing
>whether it was a status message.

This seems like a good argument for placing the response messages in a
different schema as it allows a device to filter out messages at the
header level.

Seems to be pro's and con's for each, like Edward says, "I think the
best combines features from each."

> This could significantly increase loading
>on limited capability devices. Therefore I felt it was wrong and all
status
>information should be sent untargeted.

There's differing levels of status information here I feel.

One is the status information and events generated by the device e.g.
Now.Playing when the track changes, and the informational "This is
where I'm at right now".

Then there are the directly addressed responses requesting particular
information.

The former would be untargetted, the latter to be targetted at the
inquisitor.

S
--
Stuart Booth <<a
href="/group/xAP_developer/post?postID=uZJBdJnmJ-h7yT-6zh-D8ZBGiAx8KkswgQVkhSB3A8yvkJBwmYnJ8Ncq329u_rRgmDvT78ffms9JyAv8jg">stuart@x...</a>>
xAPFramework.net - a xAP software development framework for .net

<a href="http://www.xapautomation.org/";>http://www.xapautomation.org/</a>
<a href="http://www.xapframework.net/";>http://www.xapframework.net/</a>