W3C home > Mailing lists > Public > xml-dist-app@w3.org > March 2000

Re: The Two Way Web

From: Mark Baker <mark.baker@Canada.Sun.COM>
Date: Fri, 10 Mar 2000 18:35:21 -0500
Message-ID: <38C986B9.150B4349@canada.sun.com>
To: Ken MacLeod <ken@bitsko.slc.ut.us>
CC: xml-dist-app@w3.org, devel@casbah.org
[btw, I'm not signed up for soap-discuss, so feel free to forward
my posts there yourself]

Ken MacLeod wrote:
> XML messaging does what HTTP does, just differently because no one
> wants to mess with HTTP's installed base (i.e. if it doesn't use only
> GET/PUT/POST it probably ain't gonna happen).  One of the most common
> ways to implement XML messaging is to actually tunnel those messages
> on top of HTTP's POST (and less often, GET and PUT).

Sure.  I think POST makes most sense for messaging, since its
semantics are to insert a document into a container, like a message
into a channel.

> XML messaging often suggests many different types of methods than
> GET/PUT/POST.

And HTTP supports extension methods for that reason.  But what
methods did you have in mind?  Are you sure they're necessary?
The standard HTTP methods are pretty powerful. (see below)

> Scenario one recognizes HTTP's "method" field and proposes we use it.

I assume by "method field" you mean just using your own method.

> Scenario two recognizes that that's never gonna happen, so let's
> simply declare a new successor (I use SOAP as an example).

Why won't that happen?  Both cases require the server to be
upgraded in some sense.

> I refer to a third scenario in this message above, that of tunneling a
> messaging protocol through HTTP.  That's simply a hack, a very, very
> common hack, but a hack none the less.

Why would you need to tunnel a message protocol over HTTP?  Why
not just send the XML directly over HTTP?
 
> > > Now to DWChat. getMessages() and postMessage() are both "actions" that
> > > do something much different than simply "get" a value or offer data to
> > > a function (POST).
> > >
> > > In scenario one from above, that would be:
> > >
> > >   DWChat:getMessages http://mysite.org/chat_channel_1 HTTP/1.1
> > >   DWChat:postMessage http://mysite.org/chat_channel_1 HTTP/1.1
> > >
> > > Note that some URL munging could be applied here to achieve the same
> > > effect with GET/POST, but I don't think that scales well.
> >
> > URL munging to avoid caching?
> 
> URL munging as a different technique of passing what "method" (action)
> I want the server to perform.  It's a hack that could be worse than
> tunneling.

Inserting a chat message into a chat channel is perfectly
aligned with HTTP POST semantics.  What other action do you
need the server to perform?  Can that be represented by
posting a different XML document to a sub-URI? eg.

http://mysite.org/chat_channel_1/admin/

The documents posted to that URI would represent different
adminstration actions one could take on the channel.

MB
Received on Friday, 10 March 2000 18:34:12 GMT

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