On Tue, Nov 25, 2008 at 4:05 AM, Steve Jones <[EMAIL PROTECTED]> wrote:
> 2008/11/24 Mark Baker <[EMAIL PROTECTED]>:
>> On Mon, Nov 24, 2008 at 11:45 AM, Steve Jones <[EMAIL PROTECTED]>
>> wrote:
>>> A little bit pie in the sky here, nice in theory but a killer in practice
>>>
>>> So as an example.
>>>
>>> Imagine a message about a prisoner requesting a specific training class.
>>>
>>> The message would have to include
>>
>> No, it wouldn't. The author is talking about stateless messaging -
>> though it's a little difficult to tell - and all that requires is that
>> the message contain all the information needed to understand its
>> meaning. If the sender doesn't want the message to communicate why
>> the prisoner is behind bars, then they shouldn't include it. If they
>> do, then they should. It's just that simple.
>
> Which makes it redundant from an archival perspective as it just
> includes the message which says A-B happens.

Archival for what purposes?  I think it's completely suitable to
archive the message as evidence of the information some other party
sent to you.  It might, for example, have been the first message
submitted as part of some business process and so be needed in the
future in case there's any legal issues.

>  This can be a reasonable
> approach (although I'd still recommend references, sending a URI for
> instance if using REST).   You end up with a  view of the messages
> (execution context from an RM perspective) but not the broader service
> interaction (policy, etc).

Sending references is, of course, also of great value.  But from the
point of view of the article which motivated this thread, I believe
what the author was trying to say - similar to my blog post - is that
if the sender wants the message to convey certain information, that
information needs to be in the message itself, not referenced.  You
would include references only when the reference itself is what you
want to communicate, not whatever value the reference currently
dereferences to.

For example, if I wanted to send a (separate) message to tell you what
time I sent this email, this wouldn't be a very good way to do it
(although it is 100% accurate at the moment I hit "Send");

<time>http://www.timeanddate.com/worldclock/city.html?n=188</time>

Since you mentioned archival, IMO, archival of stateful messages is
pointless, because it means that the meaning of the message can change
over time as a function of the state of some database someplace (which
isn't archived).

>> I wrote a blog post last year on some of the subtleties of stateless &
>> self-descriptive messaging;
>>
>> http://www.markbaker.ca/blog/2007/11/users-and-self-description/
>
> Interesting post.

Thanks.

Mark.

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