W3C home > Mailing lists > Public > xml-dist-app@w3.org > January 2001

Re: question about XML protocol requirements

From: Thomas D. Hite <tdhite@yahoo.com>
Date: Wed, 10 Jan 2001 22:32:25 -0800
Message-ID: <001c01c07b98$45bc55f0$89d0a8c0@tdhite>
To: <xml-dist-app@w3.org>
> The problem, as I understand it, is that the XHTML-Print document needs to
> be split into several fragments so that binary images can be interspersed
> between XHTML-Print fragments. The problem is that each XHTML-Print
fragment
> is not well-formed. Only the concatenated contents of all the XHTML-Print
> fragments is well-formed.

Pretty much why I chose not to address the issue of XHTML-Print in my
response. I don't hold a great deal of confidence that it will be supported
by constrained devices.

> I think that such a solution implies new Content-Types and rules for
> assembling them.

I think by reading twice you might find we agree. But I would restate that
my suggestion SOAP (albeit with help from HTTP 1.1) can handle this by
utilizing a multiple SOAP messages and attachments. The attachments contain
the binary data, which may be links for chunked transfers, or the data
itself if it fits, such as small pictures or icons.

----- Original Message -----
From: "Herriot, Robert" <Robert.Herriot@pahv.xerox.com>
To: "Thomas D. Hite" <tdhite@yahoo.com>; <xml-dist-app@w3.org>
Sent: Wednesday, January 10, 2001 7:06 PM
Subject: RE: question about XML protocol requirements


> I don't think that SOAP solves the problem.
>
> The problem, as I understand it, is that the XHTML-Print document needs to
> be split into several fragments so that binary images can be interspersed
> between XHTML-Print fragments. The problem is that each XHTML-Print
fragment
> is not well-formed. Only the concatenated contents of all the XHTML-Print
> fragments is well-formed.
>
> I think that such a solution implies new Content-Types and rules for
> assembling them.
>
>
>
> > -----Original Message-----
> > From: Thomas D. Hite [mailto:tdhite@yahoo.com]
> > Sent: Wednesday, January 10, 2001 9:18 AM
> > To: xml-dist-app@w3.org
> > Subject: Re: question about XML protocol requirements
> >
> >
> > > I would appreciate your thoughts on images and XML in a
> > memory constrained
> > > environment.
> >
> > With the risk of stepping out of bounds (I'm not on this particular
> > committee) or repeating old posts, I'd like to suggest
> > something related to
> > your question. I too spend time with other standards efforts,
> > some of which
> > are tightly related to device networking (like printers).
> >
> > Your question starts by discussing XHTML-Print, yet asks the
> > question of XML
> > in a constrained environment. Rather than cover the former
> > however, I'd like
> > to suggest that XML is a very convenient model for
> > constrained environments.
> >
> > Let's just take the SOAP model for discussion purposes. There is no
> > requirement, in any way shape or form, that an entire print
> > document pass in
> > a single SOAP message. If appropriate to the standards body, a
> > query/response mechanism can (should?) be adopted. Any images
> > not able to
> > fit in a single (non-chunked transfer) message would be passed across
> > multiple messages, either as a link to a potentially chunked
> > transfer, or as
> > multiple query/response pairs. The latter, though, would
> > require yet another
> > binary transfer protocol of which I'd not be a fan.
> >
> > My suggestion here is that while XHTML-Print is interesting
> > for memory and
> > CPU rich rendering devices, a SOAP (or XP) query/response
> > protocol would
> > seem more interesting as a 'general purpose' model. The
> > standards bodies I
> > work with generally have a goal of producing results sooner
> > rather than
> > later, which is an agreeable goal, so as yet they, have not
> > attempted to
> > construct such a model and have purposely shied away.
> >
> > While such a model places more burden on the device
> > requesting the print (or
> > any other rendering for that matter - such as streaming
> > audio/video), we can
> > be relatively assured that that particular device will not be memory
> > constrained since it definitely must contain the document in question.
> >
> > > Is anyone else looking at this problem?
> >
> > The UPnP printing and Technical Committees are both spending
> > plenty of time
> > on this issue.
> >
> > Tom Hite
> >
> >
> > ----- Original Message -----
> > From: "Herriot, Robert" <Robert.Herriot@pahv.xerox.com>
> > To: <xml-dist-app@w3.org>
> > Sent: Tuesday, January 09, 2001 3:41 PM
> > Subject: question about XML protocol requirements
> >
> >
> > >
> > > I have a question about the work on XML protocol requirements.
> > >
> > > I am working with several standards groups that defining
> > XHTML-Print,
> > which
> > > is XHTML-Basic plus a few page related features.
> > XHTML-Print needs to be
> > > able to reference non-XML data, such as jpeg images.
> > >
> > > Your document states in R700a that ebXML and RosettaNet are
> > solving the
> > > problem of binary data in XML and the W3C XML Protocol
> > Group is not. Those
> > > groups both solve the binary-data problem with multipart/related.
> > >
> > > We have considered a similar solution for XHTML-Print, but
> > we have one
> > > additional constraint that is not addressed by the ebXML or
> > RosettaNet
> > > solutions. Some printers have only enough memory to hold a
> > page or two of
> > a
> > > document stream. Such a printer must be able to obtain an
> > image from a
> > > nearby place in the document stream; it cannot read through
> > and buffer an
> > > entire XML document before finding the image.
> > >
> > > Is anyone else looking at this problem?
> > >
> > > Ideally there should be less than one printed page of XML text data
> > between
> > > an image and its reference. In the context of multipart/related This
> > > constraint seems to imply that:
> > >
> > > a) the XML text data must be split into multiple fragments
> > with one or
> > more
> > > images between each XML fragment,
> > > b) there must be a root object that references all of the
> > XML fragments
> > with
> > > cid's
> > > c) images must be referenced with cid's within the XML fragments.
> > >
> > > The XML-fragment concept may have problems because the XML is not
> > > well-formed until all fragments are concatenated.
> > >
> > > I would appreciate your thoughts on images and XML in a
> > memory constrained
> > > environment.
> > >
> > > Bob Herriot
> > >
> >
> >
> >
> > _________________________________________________________
> > Do You Yahoo!?
> > Get your free @yahoo.com address at http://mail.yahoo.com
> >


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Received on Wednesday, 10 January 2001 23:30:15 GMT

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