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Changing the default value of mustUnderstand to "true"

From: Hugo Haas <hugo@w3.org>
Date: Mon, 1 Jul 2002 15:52:50 -0400
To: xmlp-comments@w3.org
Message-ID: <20020701195250.GB10808@jibboom.w3.org>

Hi.

The default value of the mustUnderstand Attribute is "false"[1]:

|   The type of the mustUnderstand attribute information item is boolean
|   in the namespace "http://www.w3.org/2001/XMLSchema".
|   
|   Omitting this attribute information item is defined as being
|   semantically equivalent to including it with a value of "false" or
|   "0".

Having a header block without mustUnderstand set to "true" allows the
SOAP node supposed to process this block to ignore it as shown in
2.7.1 Forwarding Intermediaries[2]:

|   Forwarding intermediaries MUST process the message according to the
|   SOAP processing model defined in 2.6 Processing SOAP Messages. They
|   MUST also remove from the message all SOAP header blocks targeted at
|   themselves, prior to forwarding, regardless of whether these header
|   blocks were processed or ignored.  

and in 2.6 Processing SOAP Messages[3]:

|    4. Process all header blocks targeted at the node and, in the case of
|       an ultimate SOAP receiver, the SOAP body. A SOAP node MUST process
|       all SOAP header blocks targeted at it. A SOAP node MAY choose to  
|       ignore the application level processing specified by non-mandatory
|       SOAP header blocks targeted at it.                                

The probability that somebody included a header and really wants
something to happen as a result of its processing is high. The
probability that the person doesn't care if the header is ignored is
low.

For example, every header block used as examples in the primer[4]
(that I saw) uses env:mustUnderstand="true".

It therefore seems natural to make "true" the default value for
mustUnderstand.

Regards,

Hugo

  1. http://www.w3.org/TR/2002/WD-soap12-part1-20020626/#soapmu
  2. http://www.w3.org/TR/2002/WD-soap12-part1-20020626/#forwardinter
  3. http://www.w3.org/TR/2002/WD-soap12-part1-20020626/#procsoapmsgs
  4. http://www.w3.org/TR/2002/WD-soap12-part0-20020626/
-- 
Hugo Haas - W3C
mailto:hugo@w3.org - http://www.w3.org/People/Hugo/ - tel:+1-617-452-2092
Received on Monday, 1 July 2002 15:52:51 GMT

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