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RE: SWAP related query

From: Keith Swenson <kswenson@ms2.com>
Date: Tue, 20 Jun 2000 22:12:06 -0700
Message-ID: <454B1A931D1BD411A1B200B0D0209CB4150370@ms2-exchange.ms2.com>
To: Praveen Reddy <pnr_praveen@yahoo.com>
Cc: ietf-swap@w3.org, WORKGROUP4@FTPLIST.AIIM.ORG
There has been a considerable amount of debate over the issue of using
existing HTTP methods (GET / POST) or inventing new ones.  As you know, the
HTTP address specifies the location of a resource.  Your position on this
debate depends on whether you see the information being returned as 'the
resource' or 'meta-data about the resource'.  For instance, in WebDAV the
resource is a document of some sort.  PROPFIND gets a property of that
document, but never the document itself.  When the original proposal was
under discussion with members of the WebDAV working group strongly suggested
inventing new methods, especially since HTTP 1.1 defined the means to invent
new methods, which is why the draft defined new methods.

Later, we found this to be controversial and not necessarily suited to the
goals of SWAP.  The technology used to implement versions of SWAP were not
always sufficient to allow the implementation of new methods.  The purpose
of SWAP was to fit into the existing infrastructure, not to define a new one
requiring completely new implementation.  What chance is there that existing
companies would be able to deploy the 'standard'?  And then, the fact that
you can invent new methods is no reason to acutally invent them.  But the
real issue is that with SWAP, the requests are dealing directly with the
resources themselves.  Unlike WebDAV, when you get the XML representation of
a process instance, the process instance *is* the resource.  Which is why
the WfMC has decided it is very appropriate then to use GET and POST.

I would like to see a SWAP-2 proposal put together that is consistent which
is: the Wf-XML proposal, with extensions to fill in the missing
functionality, together with the definition of how to carry this over HTTP.

-Keith 
----------------------------------------------------------------
Keith D. Swenson, kswenson@ms2.com, MS2 Inc.
2440 W. El Camino Real, Mountain View, CA, 94040
tel: +1 650 623-2329,  fax: +1 650 967-7394


> -----Original Message-----
> From: Praveen Reddy [mailto:pnr_praveen@yahoo.com]
> With greetings,
> 	To whomsoever it may concern
> -------------------------------------------
> We into a devlepoment programme for a generic workflow
> engine based on SWAP.
> The problem we are facing while coding on the server
> part is as follows:
> 
> 	In the document WFMC-TC-1023(dated 1-May-2000 version
> 1.0) the TRANSPORT LAYER BINDINGS section
> proposes the use of HTTP method POST for sending the
> data encoded iin XML from the client to the
> Server.
> 
> But if we go on the lines of WebDAV or SWAP internet
> drafts the usage of protocol specific methods 
> is suggested.
> Example PROPFIND is method which the client sends to
> the server for getting the properties of the RESOURCE.
> Even the presentation my Mr. Surender Reddy(chairman
> SWAP workging group) has a slide 
> which i am sending as attachment.
> The attached slide basically throws light on the
> Method CREATEPROCESSINSTANCE.
> 
> 
> The confusion is that we are not able to decide to
> which STANDARD to stick to.
> The other thing we may do is to CONSIDER both the
> situations while coding the SWAP API.
> 
> I will be highly obliged if you throw some light on
> this issue.
> 
> Thanking you,
> Praveen Reddy,
> S/W engg.
> Integra Micro Systems (p) ltd,
> Bangalore
> India.
> mail -  pnr_praveen@yahoo.com
> __________________________________________________
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> 
Received on Wednesday, 21 June 2000 01:12:01 UTC

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