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RE: Proposed resolution: issues 78, 16

From: Jacek Kopecky <jacek@idoox.com>
Date: Thu, 9 Aug 2001 17:04:16 +0200 (CEST)
To: Frank DeRose <frankd@tibco.com>
cc: <xml-dist-app@w3.org>
Message-ID: <Pine.LNX.4.33.0108091648220.14187-100000@mail.idoox.com>
 Frank,
 thinking about it, this solution might be as good as the
"encoding-independent with start attribute" one except for two
points:
 1) the whole body must be parsed in case of "root" attribute
missing
 2) some special implementations might want to choose not to
implement the optional section-5 encoding, but they might like to
implement RPC.
 You see, my point against the ties was that the actual RPC
message would be different if the user used a different encoding.
They can do that now as well except that the RPC element must be
a section-5 encoded struct.

                            Jacek Kopecky

                            Idoox
                            http://www.idoox.com/




On Wed, 8 Aug 2001, Frank DeRose wrote:

 > This email outlines what I believe to be the simplest solution to issues 78
 > and 16. This solution corresponds roughly to solution "c" suggested by Noah.
 > Both Noah and Jacek are unhappy with this solution, but it is one logical
 > possibility, so we should consider it. It solves issues 78 and 16, it does
 > the least violence to the current spec, and it offers backwards
 > compatibility to a large number of current implementations.
 >
 > Briefly, this solution consists of 4 parts:
 >
 > 1.) Explicitly acknowledge that Section 7 MUST be used in conjunction with
 > Section 5.
 > 2.) Rewrite Section 5.6 to improve its clarity.
 > 3.) Rewrite the last paragraph of Section 7 to prohibit "boxcarring" and to
 > provide explicit instructions on how to handle RPC calls with 0 out params
 > and void return type.
 > 4.) Add definitions for RPC terms to glossary.
 >
 > I discuss each part in more detail below.
 >
 > 1.) Explicitly acknowledge that Section 7 MUST be used in conjunction with
 > Section 5.
 > Section 7 uses terms like "struct" and "accessor," which are defined in
 > Section 5. Consequently, Section 7 is implicitly dependent on the default
 > encoding defined in Section 5. Yet, Section 7 also states that it can be
 > used in conjunction with other encodings:
 >
 > "Although it is anticipated that this representation is likely to be used in
 > combination with the encoding style defined in section 5, other
 > representations are possible. The SOAP encodingStyle attribute (see section
 > 4.3.2) can be used to indicate the encoding style of the RPC invocation
 > and/or the response using the representation described in this section.
 > ...
 > As noted above, RPC invocation and response structs can be encoded according
 > to the rules in section 5, or other encodings can be specified using the
 > encodingStyle attribute (see section 4.1.1)."
 >
 > It is clearly a contradiction for Section 7 to be based on terms defined in
 > the default encoding and at the same time to state that other encoding
 > styles can be used. To eliminate this contradiction, we should delete the
 > two paragraphs quoted above and add the following text somewhere in Section
 > 7:
 >
 > <FranksVersion1ofRewriteToMakeSection7DependentOnSection5>
 > The RPC representation defined in section 7 MUST be used in conjunction with
 > the encoding style defined in Section 5. The use of an encoding style other
 > than the one defined in Section 5 MUST be interpreted to mean that an RPC
 > representation other than the one defined in Section 7 is being used.
 > </FranksVersion1ofRewriteToMakeSection7DependentOnSection5>
 >
 > 2.) Rewrite Section 5.6 to improve clarity.
 > Once Section 7 has been made explicitly dependent on Section 5, it becomes
 > possible to use the "root" attribute defined in Section 5.6 to distinguish
 > the serialization root in the Body of an RPC message from other elements
 > (such as multi-ref elements) that may also appear in the Body. I have
 > already proposed this rewrite of Section 5.6 in another email. I repeat it
 > here:
 >
 > <ProposedRewriteOfSection56>
 > The SOAP root attribute MAY be used to divide independent elements at the
 > same nesting level into 2 categories: those that are serialization roots and
 > those that are not. The purpose of marking an element as a serialization
 > root is to distinguish it as a starting point for processing. This is
 > similar to the way the "start" parameter in the MIME multipart/related media
 > type "points, via a content-ID, to the body part that contains the object
 > root."
 >
 > When not explicitly forbidden, there may be multiple serialization roots at
 > the same nesting level (for example, in the SOAP Header).
 >
 > The root attribute can have one of two values, "1" or "0". The value "1"
 > indicates that an element is a serialization root. The value "0" indicates
 > that an element is not a serialization root. The attribute does not have a
 > default value. All independent elements without the root attribute MUST be
 > assumed to be non-roots except in the case where no element has the root
 > attribute with a value of 1. In that case, the first independent element
 > at that level without the root attribute MUST be considered to be the single
 > serialization root at that level. If no such element exists, it is an error.
 > </ProposedRewriteOfSection56>
 > A comment is in order on the "except" clause in the 5th sentence in the
 > third paragraph and the sentence that follows it in the proposed rewrite.
 > Some implementations have been using order to determine which element in the
 > body is the request/response element (in spite of the fact that SOAP 1.1
 > doesn't provide any support for this). Namely, some implementations
 > interpret the first lexical element as the request/response element and all
 > subsequent elements as multi-reference elements, while others interpret the
 > last lexical element as the request/response element and all preceeding
 > elements as multi-reference elements. The "except" clause and the sentence
 > that follows are intended to provide backwards compatibility for the first
 > category of implementations. Unfortunately, AFAIK, there's no way to
 > accomodate both categories.
 >
 > I have attached a table of possible distributions of the root attribute on
 > various elements in a nesting level to demonstrate that the proposed rewrite
 > covers all possible cases. I ask members of the WG to examine this table
 > carefully to make sure I haven't made any errors or overlooked anything.
 >
 > 3.) Rewrite the last paragraph of Section 7 to prohibit boxcarring and to
 > provide explicit instructions for handling RPC calls with 0 out parameters
 > and void return type.
 > There seems to be general consensus among WG members that boxcarring ought
 > to be prohibited in the RPC representation defined in Section 7. There also
 > seems to be general consensus among WG members on how to handle RPC calls
 > with 0 out parameters and void return type. The consensus of the WG on these
 > two issues is summarized in the following rewrite of the last paragraph of
 > Section 7.1:
 >
 > <FranksVersion7OfSection71>
 > The Body of an RPC message MUST contain one and only one serialization root.
 > In the case of an RPC request message, this root is the RPC request element.
 > In the case of an RPC response message, this root is the RPC response
 > element (when the RPC succeeded) or an RPC fault element (when the RPC
 > failed).
 >
 > In the case of successful execution of an RPC with a void return type and no
 > [out] parameters, the Body of the RPC message MUST contain only the RPC
 > response element and that element MUST be empty.
 > </FranksVersion7OfSection71>
 >
 > 4.) Add definitions for RPC terms to glossary.
 > Members of the WG tend to use terms inconsistently when referring to RPC.
 > For example, the term "response" is used to refer to the entire SOAP message
 > (envelope), to the Body of the message, or to the element inside the Body
 > representing the out parameters. I propose that we add the following
 > definitions to the glossary and stick to them when discussing RPC.
 >
 > <FranksVersion3OfRPCTerms>
 > RPC message: a SOAP message (SOAP Envelope) containing an RPC request
 > element, an RPC response element, or an RPC fault element in its Body.
 >
 > RPC response message: a SOAP message (SOAP envelope) containing an RPC
 > response element or an RPC fault element in its Body.
 >
 > RPC request message: a SOAP message (SOAP Envelope) containing an RPC
 > request element in its Body.
 >
 > RPC element: inside the Body of an RPC message the serialization root that
 > represents the RPC request element, the RPC response element, or the RPC
 > fault element.
 >
 > RPC request element: inside the Body of an RPC request message the
 > serialization root that represents the [in] part of the RPC.
 >
 > RPC response element: inside the Body of an RPC response message the
 > serialization root that represents the [out] part of the RPC.
 >
 > RPC fault element: inside the Body of an RPC response message the
 > serialization root that consists of the SOAP Fault element resulting from an
 > RPC fault.
 > </FranksVersion3OfRPCTerms>
 > Frank DeRose
 > TIBCO Software Inc.
 > 3165 Porter Dr
 > Palo Alto, CA 94303
 > 650-846-5570 (vox)
 > 650-846-1267 (fax)
 > frankd@tibco.com
 > www.tibco.com
 >
 >
Received on Thursday, 9 August 2001 11:04:19 GMT

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