[emergency-msg] Review of CAP Issue # 13

ISSUE: 13 - Concern about 
validity of the XML Schema.

 

DESCRIPTION: The normative 
XML Schema in the CAP specification is improperly defined and will either 
generate validation errors or be rewritten to a form which conforms to XML 
Schema when input to common XML Schema processing tools. A 
major source of the problems is the fact that what should be anonymous simple 
types in the CAP schema are encoded with "name" attributes and are thus not 
anonymous. For instance, the CAP schema defines the element msgType 
as:

 

<element name = 
"msgType">

  <simpleType name = 
"msgType" >

    
<restriction base = "string">

    
...

    
</restriction>

  
</simpleType>

</element>

 

A proper definition of the 
msgType element would *not* include the "name" attribute in the "simpleType" 
element. Thus, the proper definition would be:

 

<element name = 
"msgType">

    
<simpleType>

      
<restriction base = "string">

      
...

      
</restriction>

    
</simpleType>

</element>

 

   This 
improper use of XML Schema occurs at least 10 times in the CAP schema (I may 
have missed a couple...)

    
Given 
that most well written XML Schema processors will rewrite or reject the 
normative CAP schema, it is hard to understand the justification for proposing a 
standard that contains a flawed normative definition. In this case, for 
interoperability to be had, it is necessary to assume that all XML Schema 
processors will either ignore or rewrite the offending elements of the schema in 
a consistent manner. While this appears to be the case so far, it introduces a 
risk of interpretation that is not appropriate for a standard such as CAP. For a 
standard such as CAP, it must be recognized that misinterpretations of CAP 
messages can lead to life-or-death consequences. Such a standard should only 
be accepted if it has achieved the highest possible levels of clarity and 
quality.

http://lists.oasis-open.org/archives/emergency-comment/200403/msg00020.html

 

 

PROPOSED CHANGE:  Ensure CAP meets the syntax as specified 
in the W3C XML 1.0 (Third Edition) (http://www.w3.org/TR/REC-xml/#sec-well-formed 
)

 

DISCUSSION: The current CAP 
1.0 was corrected for syntax and structure issues before release. 

 

RECOMMENDATION:  Close issue - no action 
taken

 

To unsubscribe from this 
mailing list (and be removed from the roster of the OASIS TC), go to http://www.oasis-open.org/apps/org/workgroup/emergency-msg/members/leave_workgroup.php.