Extending the Manifest

["Adams, Robert" <robert.adams@intel.com>]

Recent mail on this list mentioned the manifest and metadata.  There isn't
time to provide everything anyone would want in xml packaging now, but a
simple extension mechanism would enable the work done here to provide the
basis for future development

We would like to propose a manifest extension mechanism (modeled on soap's
extensible headers).  The idea is to provide a ManifestExtension element
that can contain an element from another namespaces.  If the namespace for
the extension element is understood, the extension can be used.  Otherwise
it cannot.  An attribute on the Manifest Extension element indicates whether
it is necessary to understand the extension.

What this is for:  If someone defined an RDF metadata description of
packages it could be included in a ManifestExtention.  That could be an
optional addition, used to allow sophisticated searches on packages, but not
necessary to understand packages.  Particular uses of ebXML's packaging
could also add W3C xml digital signature as an extension or future W3C XML
Encryption XML information, or could add an index value.

The main point of this is that it would allow the ebxml packaging work to be
the basis for other xml packaging additions rather than other groups having
to reinvent what ebxml has already done.

Proposal:

	Add ManifestExtension to the contents of DocumentReference element
and Manifest element (and correct DocumentDescription to make it optional
and DocumentReference to allow the sequence only once as in the DTD)

	<element name="Manifest">
		<complexType>
			<sequence>
				<element ref="DocumentReference"
					minOccurs="0" maxOccurs="unbounded"
/>
				<element ref="ManifestExtension"
					minOccurs="0" maxOccurs="unbounded"
/>
			</sequence>
		</complexType>
	</element>
	
	<element name="DocumentReference">
		<complexType>
			<sequence>
				<element ref="DocumentDescription"
					minOccurs="0" />
				<element ref="DocumentLabel" />
				<element ref="DocumentID" />
				<element ref="ManifestExtension"
					minOccurs="0" maxOccurs="unbounded"
/>
			</sequence>
		</complexType>
	</element>
	
	<!-- Elements contained in ManifestExtension must be namespace
		qualified.  If the namespace is not understood and the
mustUnderstand
		attribute is set to true, then the contents of the
		DocumentReference should not be used. -->
	<element name="ManifestExtension">
		<complexType>
			<sequence>
				<any namespace="##other"
processContents="skip" />
			</sequence>
			<attribute name="mustUnderstand" type="boolean"
				use="optional" value="true" />
		</complexType>
	</element>


	Robert Adams
	mailto:Robert.Adams@intel.com
	MS JF3-212
	2111 NE 25th Ave
	Hillsboro, OR   97124    USA
	phone: +1.503.264.9424; cell: +1.503.709.3259; FAX: +1.503.264.3375