Open Trading Protocol (CDATA, etc)(was BASE64 section support)

Chris Smith smith at interlog.com
Mon Feb 9 05:10:17 GMT 1998


On Sat, 7 Feb 1998, Don Park wrote:

> I am not sure if support for embedded binary data has been brought up in the
> WG but I am, frankly, very disappointed with the lack of support.  CDATA is
> awfully inadequate.  The Open Trading Protocol (OTP) proposal has a need to
> embed signature within OTP documents and it uses <![CDATA[ for embedding.
> For occasional occurrance of ]]>, OTP states:
> 
> "Any CDATA end sequences ("]]>") within the data are replaced by
> "]]]]><![CDATA[>" in order to escape
> the CDATA end sequence"

I think you are lifting this a little out of context. The item you
referenced is from the specification on canonicalization. As well, it
was one of several design choices going into OTPv0.9, which are likely
to be the subject of cooler heads. More to the point, that item refers
to *all* data in elements.

A more relevant area is what the Open Trading Protocol does NOT
handled. The best example here is order description (often known as
Invoice). We felt that we could never handle all needs, and we needed
to allow for both simple and complex solutions, and both current and
future solutions.

As a result, the element content is ANY, while we have a ContentFormat
attribute that lets you indicate the following: XML, PCDATA, BASE64,
HTML, MIME, plus a user-defined option. (There is a remaining
discussion topic re splitting into ContentFormat and ContentEncoding,
which I hope is actually accomplished.)

This, I think, is a reasonable compromise. Although it does not lock
down the protocol completely, making implementation more difficult, it
allows for XMl/EDI, simple plain text, and HTML browser displayed text
or graphic offers (yes - you could essentially have an invoice that
contained a picture of the item you are purchasing).

(for more details, http://www.otp.org )

In our terms, all a <![BASE64[ construct would allow is the possible
removal of a ContentEncoding layer.

---------------------------------------------------------------------------
 Chris Smith                                          <smith at interlog.com>



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