Issue 25 Proposal

Background
 

Issue 25  [1] deals with SOAP 1.1 "trailers" which are sub elements of the SOAP envelope following the body.  The only wording in the SOAP 1.1 specification [2]  which talks about headers is point number 3 under the definition of envelope (my italics):

1.  Envelope

• The element name is "Envelope".
• The element MUST be present in a SOAP message
• The element MAY contain namespace declarations as well as additional attributes. If present, such additional attributes MUST be namespace-qualified. Similarly, the element MAY contain additional sub elements.  If present these elements MUST be namespace-qualified and MUST follow the SOAP Body element.

A sender wishes to include a checksum of body contents, but the sending device does not have enough storage capacity to buffer the body before sending.  Hence the checksum must be sent physically after the body, and cannot be included in a header element.

Proposed Glossary [3] Changes
 

I would suggest that the definitions of header and body include their location within the envelope (new text in italics):

XMLP header

A collection or zero or more XMLP blocks which may be targeted at any XMLP receiver within the XMLP message path.  An XMLP header is the first element within an XMLP envelope.

XMLP body

A collection or zero, or more XMLP blocks targeted at the ultimate XMLP receiver within the XMLP message path.  An XMLP body follows the XMLP header within an XMLP envelope.

And the following new definition:

XMLP trailer element

A sub element of an XMLP envelope which follows the XMLP body.  Trailer elements are NOT comprised of XMLP blocks.  However, references to trailer elements may be contained in XMLP blocks.

Blocks within an XMLP header may refer to trailer elements.  Whenever such a block is targeted at an XMLP processor and the block contains the MUST UNDERSTAND attribute, the XMLP processor must store the body in order to process the header block before the body.  If the block does NOT contain the MUST UNDERSTAND attribute, the XMLP processor should store the body if it is capable of doing so.

Blocks within an XMLP body may also refer to trailer elements.  The XMLP processor makes these elements available to ultimate receiver of the body.
 

• This assumes that XMLP will contain a facility for specifying the order in which blocks should be processed unrelated to the physical ordering within the envelope.  Therefore, the only reason to physically order data is that it is not possible to construct and store the entire message before sending.
• This only helps storage constrained senders.  Storage constrained receivers will do better if blocks refer to data located in the header.
• This proposal does not allow a sender to decide to add an XMLP block after the header has been sent.