ALex,
See inline
Abbie
-----Original Message-----
From: Alex Rousskov [mailto:rousskov(_at_)measurement-factory(_dot_)com]
Sent: Monday, April 21, 2003 1:45 PM
To: ietf-openproxy(_at_)imc(_dot_)org
Subject: RE: SOAP and OCP
On Mon, 21 Apr 2003, Abbie Barbir wrote:
Try w3c (SOAP 1.2)
http://www.xml.org
http://www.xml.com/pub/a/2003/02/26/binaryxml.html
http://www.w3.org/TR/soap12-af/
OK. So it looks like we have at least two choices when it
comes to transmitting opaque data over SOAP. First, we can
base64-encode it. The "binaryxml.html" document argues that
encoding is the right way to go because it lets us stay
within XML boundaries. On the other hand, encoding is
expensive (CPU and bandwidth wise). The second option is to
use MIME-like "attachments".
Yes, true, this is why I said that there are ways of doing it.
SO Agree.
The worst part is that there is no "standard" way to transmit
opaque data over SOAP yet. Implementations use different
approaches and may not be compatible. Please correct me if I am wrong.
Agree
OCP is about exchanging opaque data and metadata. XML does
not support opaque data well. That is why SOAP does not
support opaque data well. From this point of view, SOAP is
the wrong protocol to base OCP on -- the primary OCP function
is not well supported. Other factors may be more important though.
If OCP is built on top of SOAP, do you expect any
existing web services to be able to act as callout
servers "as is",
without _any_ modifications? Or do you expect modification of
existing services to support OCP-over-SOAP to be "easier" than
similar modification to support OCP-over-notSOAP?
Yes, web services uses SOAP and this will allow OPES to be plugged
into that area (as opposed to be a competitor). The short
answere to
your question about modifications is Yes. By definition a
web services
once discovered and its description is obatianed is immediatly
interoperable. On the otherhand, a schema of OCP can be
written that
could be used by the web services server that he will use
to become an
OPES Callout server.
I am not sure I understand the answer. What does it mean to
be "immediatly interoperable by definition"? My understanding
is that any existing web service can already participate in
an OPES system "as is" as long as the OPES processor using
the service supports SOAP. However, such participation is
outside of OCP scope because OCP is not SOAP; OCP is a
stand-alone protocol that has features not described in SOAP
specs. To support OCP, a web service must be modified.
True, that is what I mean.
In other words, SOAP may be used as an OPES callout protocol
(from architectural point of view). However, the protocol we
are working on (OCP), is not identical to SOAP (but can be
implemented on top of SOAP). Modifications would be required
for existing web services to support OCP.
very true
Is my understanding correct? If it is, we may have a good compromise
available: treat both OCP and SOAP as possible callout
protocols and make sure that OPES framework is not OCP- or
SOAP-specific. OPES implementations will use the most
appropriate protocol for their needs.
Comments?
Alex.
I would love that.
abbie