XDS.b Implementation
This page is a placeholder for future XDS.b Implementation Notes
Rruggeri 15:49, 26 July 2007 (CDT)
If the Profile Implementation Template is useful feel free to use it. If not, feel free to improve it. :-))
kevino 12:26, 27 July 2007 (PDT)
Generating Proxies using SOAP Tools
There are some general guidelines to follow when generating proxies, especially for complex WSDL/schemas such as the ones included in XDS.b, that will make your life much, much easier.
The first one is use generic, non-strongly typed WSDL for development purposes, that is for the purpose of generating the proxy.
Strongly typed WSDL will force the infrastructure to go through all the xml type definitions and generate classes for them. The mapping between XSD and object oriented constructs is not always straightforward and you might run into some problems even with valid instances.
This approach works well for your average weather web service, but not for more complex scenarios like the ones we have to deal with.
Furthermore, generating classes through proxies will force turning the XML in the SOAP message to objects where most likely you will have to deal with the XML anyways. This step can also be somewhat resource intensive as it forces a validation of the whole message which is usually avoided in production environments with high transaction volume.
Generic WSDL for development replace the types of the input/output SOAP messages with generic xs:any types. By generating the proxy from that modified WSDL you get a method signature that basically only deals with raw XML documents for input and output. Yes, you lose "automatic" XSD validation, but you can always put that step back in if you want and make it optional when you go to production.
Axis2 Proxy Generation on Windows
The Axis2 tool for WSDL to Java classes (WSDL2Java) exhibits the following problem when running on Windows, and using WSDLs referencing the HL7 V3 schema:
Caused by: org.apache.axis2.schema.SchemaCompilationException: can not find the parent schema for the complex type {urn:hl7-org:v3}CS from the parent schema urn:hl7-org:v3
The reason for this seems to be the handling of file paths in Java on Windows: while URLs require forward slashes as path separators, system file paths use the Windows convention of back slashes. When one schema file references another schema file in a different directory, it uses relative paths with URL syntax, and this confuses Axis2.
One possible workaround on Windows is to use Cygwin, which provides a UNIX-like environment on Windows, including a BASH shell. This still requires a small change to the Axis2 distribution: replace the $AXIS2_HOME/bin/axis2.sh with the following:
#!/bin/sh # Copyright 2001,2004-2006 The Apache Software Foundation # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # ---------------------------------------------------------------------------- # Axis2 Script # # Pre-requisites # - setenv.sh must have been called. # # AXIS2_HOME Home of Axis2 installation. If not set I will try # to figure it out. # # JAVA_HOME Must point at your Java Development Kit installation. # # ----------------------------------------------------------------------------- # Get the context and from that find the location of setenv.sh . `dirname $0`/setenv.sh #add any user given classpath's USER_COMMANDS="" prearg="" for arg in "$@" do if [ "$arg" != -classpath ] && [ "$arg" != -cp ] && [ "$prearg" != -classpath ] && [ "$prearg" != -cp ] then USER_COMMANDS="$USER_COMMANDS ""$arg" fi if [ "$prearg"=-classpath ] || [ "$prearg"=-cp ] then AXIS2_CLASSPATH="$arg":"$AXIS2_CLASSPATH" fi prearg="$arg" done "$JAVA_HOME/bin/java" -Xmx80m -classpath "$AXIS2_CLASSPATH" \ -Daxis2.xml="$AXIS2_HOME/conf/axis2.xml" -Daxis2.repo="$AXIS2_HOME/repository" $USER_COMMANDS
Then you can run the proxy generator like this:
/usr/local/axis2-1.3/bin/wsdl2java.sh --noMessageReceiver --noWSDL -uri <path-to-WSDL> -o <path-to-generated-code>
Transition from MTOM to MTOM/XOP
[This section, written in the Fall of 2007, is not a correct interpretation of the MTOM/XOP standard. This section has been replaced by xxx]
The XDS.b supplement, as published, documents the use of the MTOM [standard]. Now that the testing season has started, we have found that this choice of standards is not appropriate. This section documents the reason for the change and the necessary updates to the XDS.b supplement. This material will be formatted as a formal Change Proposal to the XDS.b profile later this season. These change will be in effect for January 2008 North American Connectathon.
Choice of Standards
In many ways XDS.b is a technology update to the original XDS (now called XDS.a). The move from SOAP with Attachments to MTOM is part of this update. In selecting MTOM as the replacement we thought we were tracking the industry correctly. The real situation is slightly more complicated. There are two relevant standards here, [MTOM] and [XOP] ([XOP FAQ]). As originally published, XDS.b references MTOM without XOP. This update changes that to be MTOM with XOP. This change is being made for the following reasons:
- In common/casual usage, from my own informal survey, the term MTOM is used to mean MTOM with XOP
- It is pretty hard to find discussion of MTOM without XOP.
- The following packages are known to support MTOM/XOP: Apache Axis2, .NET. My informal survey of web-available material indicates the same for JBOSS and Oracle.
- Several sites document performance issues when using MTOM without XOP when used with large attachments. From and XDS point of view this means large documents. I believe this comes from using XML parsers that are not optimized for dealing with such large text nodes within the XML. More on this below where I discuss technology issues.
- .NET ([documentation]) uses a strategy of using MTOM for small documents and MTOM/XOP for large documents.
Change Proposal
The following changes are proposed for the Provide and Register Document Set-b transaction:
- The Document Source actor may send either MTOM or MTOM/XOP formats.
- The Document Repository actor shall accept both MTOM and MTOM/XOP formats.
The following changes are proposed for the Retrieve Document Set transaction:
- The Document Repository actor may send either MTOM or MTOM/XOP formats.
- The Document Consumer actor shall accept both MTOM and MTOM/XOP formats.
Discussion of Standards
To understand this change one needs to understand parts of MTOM, XOP, and SOAP with Attachments standards.
Soap with Attachments (SwA) uses mime/multipart structure. The top level wrapper for this standard looks like:
MIME-Version: 1.0 Content-Type: Multipart/Related; boundary=MIME_boundary; type=text/xml Content-Description: XDS.a example using SOAP with Attachments --MIME_boundary Content-Type: text/xml; charset=UTF-8 Content-Transfer-Encoding: 8bit <?xml version='1.0' ?> <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"> <SOAP-ENV:Body> <!-- Metadata Goes Here --> ... <ExtrinsicObject id="mydocument" /> ... </SOAP-ENV:Body> </SOAP-ENV:Envelope> --MIME_boundary Content-Type: text/xml Content-ID: <mydocument> document contents --MIME_boundary--
This is how XDS.a works. The id attribute of each ExtrinsicObject element is available as a multipart Part. The id attribute corresponds with the Content-ID value (angle brackets required). If the document is base64 encoded then additional headers in the mydocument part header assert that.
MTOM takes a radically different approach. This is what is documented in the XDS.b profile as it stands now. The same example looks like:
MIME-Version: 1.0 Content-Type: type=text/xml Content-Description: XDS.b example using MTOM <?xml version='1.0' ?> <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"> <SOAP-ENV:Body> <!-- Metadata Goes Here --> ... <ExtrinsicObject id="mydocument" /> ... <Document id="mydocument">base64 encoded document contents</Document> ... </SOAP-ENV:Body> </SOAP-ENV:Envelope>
This encoding does not use a multipart. The base64 encoded bits of the document are transmitted as a text node which is a child of the <Document/> element.
MTOM/XOP looks a little like both of the above.
MIME-Version: 1.0 Content-Type: Multipart/Related; boundary=MIME_boundary; type=text/xml Content-Description: MTOM/XOP example --MIME_boundary Content-Type: text/xml; charset=UTF-8 Content-Transfer-Encoding: 8bit Content-ID: <claim061400a.xml@claiming-it.com> <?xml version='1.0' ?> <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"> <SOAP-ENV:Body> <!-- Metadata Goes Here --> ... <ExtrinsicObject id="mydocument" /> ... <Document id="mydocument"> <Include href="cid:1.urn:uuid:BC47538ED684E0A2D41194546709563@apache.org" xmlns="http://www.w3.org/2004/08/xop/include" /> </Document> ... </SOAP-ENV:Body> </SOAP-ENV:Envelope> --MIME_boundary Content-Type: text/xml Content-Transfer-Encoding: binary Content-ID: <cid:1.urn:uuid:BC47538ED684E0A2D41194546709563@apache.org> binary encoding of document contents --MIME_boundary--
The id attribute of the ExtrinsicObject metadata element matches the id attribute of a Document element also in metadata. That Document element has a child element <Include> whose href attribute names the mime Part that contains the document contents. To the best of my understanding, here is were XOP offers a benefit. Instead of requiring base64 encoding, these attachment can be binary encoded. Much better for large documents.
Example Retrieve Document Set transaction
Below is an example request and response from a Retrieve Document Set transaction taken from a trace of the Public Registry. The original was chunk encoded (included header Transfer-Encoding: chunked). This encoding has been removed for readability. To make this a valid transaction either the chunked encoding would have to be redone or a Content-Length header would have to be added.
There are two examples here, the first returns MTOM, the second returns MTOM/XOP. The second example is included because several implementations of MTOM/XOP do not use the Content-Type header for passing an accurate mime type, instead passing the generic value application/octet-stream. This is allowed by the XOP standard. Because of this, one must rely on the XDS metadata mimeType attribute for the Provide and Register Document Set.b transaction and on the MimeType element in the Retrieve Document Set transaction. The second example only shows the response since the request could be the same.
Request
POST /axis2/services/xdsrepositoryb HTTP/1.1 Content-Type: application/soap+xml; charset=UTF-8; action="urn:ihe:iti:2007:RetrieveDocumentSet" User-Agent: Axis2 Host: localhost:9087 <?xml version='1.0' encoding='UTF-8'?> <soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope" xmlns:wsa="http://www.w3.org/2005/08/addressing"> <soapenv:Header> <wsa:To>http://localhost:9087/axis2/services/xdsrepositoryb</wsa:To> <wsa:MessageID>urn:uuid:D565D5833AE3D90AFD1198851327915</wsa:MessageID> <wsa:Action>urn:ihe:iti:2007:RetrieveDocumentSet</wsa:Action> </soapenv:Header> <soapenv:Body> <RetrieveDocumentSetRequest xmlns="urn:ihe:iti:xds-b:2007" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="urn:ihe:iti:xds-b:2007 file:/Users/bill/ihe/Frameworks/ITI-4/XDS.b/schema/IHE/XDS.b_DocumentRepository.xsd"> <DocumentRequest> <RepositoryUniqueId>1.19.6.24.109.42.1</RepositoryUniqueId> <DocumentUniqueId>129.6.58.91.13297</DocumentUniqueId> </DocumentRequest> <DocumentRequest> <RepositoryUniqueId>1.19.6.24.109.42.1</RepositoryUniqueId> <DocumentUniqueId>129.6.58.91.13298</DocumentUniqueId> </DocumentRequest> </RetrieveDocumentSetRequest> </soapenv:Body> </soapenv:Envelope>
Response
The documents included in the response are MTOM encoded (see <xdsb:Document/> element).
HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Type: application/soap+xml; action="urn:ihe:iti:2007:RetrieveDocumentSetResponse";charset=UTF-8 Date: Fri, 28 Dec 2007 14:15:28 GMT <?xml version='1.0' encoding='UTF-8'?> <soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope" xmlns:wsa="http://www.w3.org/2005/08/addressing"> <soapenv:Header> <wsa:Action>urn:ihe:iti:2007:RetrieveDocumentSetResponse</wsa:Action> <wsa:RelatesTo>urn:uuid:D565D5833AE3D90AFD1198851327915</wsa:RelatesTo> </soapenv:Header> <soapenv:Body> <xdsb:RetrieveDocumentSetResponse xmlns:xdsb="urn:ihe:iti:xds-b:2007"> <rs:RegistryResponse xmlns:rs="urn:oasis:names:tc:ebxml-regrep:xsd:rs:3.0" status="urn:oasis:names:tc:ebxml-regrep:ResponseStatusType:Success"/> <xdsb:DocumentResponse> <xdsb:Document>VGhpcyBpcyBteSBkb2N1bWVudC4KCkl0IGlzIGdyZWF0IQoK</xdsb:Document> <xdsb:RepositoryUniqueId>1.19.6.24.109.42.1</xdsb:RepositoryUniqueId> <xdsb:DocumentUniqueId>129.6.58.91.13297</xdsb:DocumentUniqueId> <xdsb:mimeType>text/plain</xdsb:mimeType> </xdsb:DocumentResponse> <xdsb:DocumentResponse> <xdsb:Document>VGhpcyBpcyBteSBzZWNvbmQgZG9jdW1lbnQuCgpJdCBpcyBncmVhdCEKCg==</xdsb:Document> <xdsb:RepositoryUniqueId>1.19.6.24.109.42.1</xdsb:RepositoryUniqueId> <xdsb:DocumentUniqueId>129.6.58.91.13298</xdsb:DocumentUniqueId> <xdsb:mimeType>text/plain</xdsb:mimeType> </xdsb:DocumentResponse> </xdsb:RetrieveDocumentSetResponse> </soapenv:Body> </soapenv:Envelope>
Response in MTOM/XOP format showing the slack encoding of mimeType. Note the header in the second Part:
- Content-Type: application/octet-stream
HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Type: multipart/related; boundary=MIMEBoundaryurn_uuid_3BE45FAC62CF0568A81199380869988; type="application/xop+xml"; start="0.urn:uuid:3BE45FAC62CF0568A81199380869989@apache.org"; start-info="application/soap+xml"; action="urn:ihe:iti:2007:RetrieveDocumentSetResponse" Date: Thu, 03 Jan 2008 17:21:04 GMT --MIMEBoundaryurn_uuid_3BE45FAC62CF0568A81199380869988 Content-Type: application/xop+xml; charset=UTF-8; type="application/soap+xml" Content-Transfer-Encoding: binary Content-ID: <0.urn:uuid:3BE45FAC62CF0568A81199380869989@apache.org> <?xml version='1.0' encoding='UTF-8'?> <soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope" xmlns:wsa="http://www.w3.org/2005/08/addressing"> <soapenv:Header> <wsa:Action>urn:ihe:iti:2007:RetrieveDocumentSetResponse</wsa:Action> <wsa:RelatesTo>urn:uuid:A920DC9E26409B53231199380832547</wsa:RelatesTo> </soapenv:Header> <soapenv:Body> <xdsb:RetrieveDocumentSetResponse xmlns:xdsb="urn:ihe:iti:xds-b:2007"> <rs:RegistryResponse xmlns:rs="urn:oasis:names:tc:ebxml-regrep:xsd:rs:3.0" status="urn:oasis:names:tc:ebxml-regrep:ResponseStatusType:Success"/> <xdsb:DocumentResponse> <xdsb:Document> <xop:Include href="cid:1.urn:uuid:3BE45FAC62CF0568A81199380869990@apache.org" xmlns:xop="http://www.w3.org/2004/08/xop/include"/> </xdsb:Document> <xdsb:RepositoryUniqueId>1.19.6.24.109.42.1</xdsb:RepositoryUniqueId> <xdsb:DocumentUniqueId>1.2.3.4.100000022002209036.1196211173506.1</xdsb:DocumentUniqueId> <xdsb:mimeType>text/xml</xdsb:mimeType> </xdsb:DocumentResponse> </xdsb:RetrieveDocumentSetResponse> </soapenv:Body> </soapenv:Envelope> --MIMEBoundaryurn_uuid_3BE45FAC62CF0568A81199380869988 Content-Type: application/octet-stream Content-Transfer-Encoding: binary Content-ID: <1.urn:uuid:3BE45FAC62CF0568A81199380869990@apache.org> Detailed document removed for clarity --MIMEBoundaryurn_uuid_3BE45FAC62CF0568A81199380869988
Example Provide and Register Document Set-b transaction
Below is an example request and response from a Provide and Register Document Set-b transaction taken from a trace of the Public Registry. The original was chunk encoded (included header Transfer-Encoding: chunked). This encoding has been removed for readability. To make this a valid transaction either the chunked encoding would have to be redone or a Content-Length header would have to be added.
Request
POST /axis2/services/repositoryBonedoc HTTP/1.1 Content-Type: multipart/related; boundary=MIMEBoundaryurn_uuid_806D8FD2D542EDCC2C1199332890718; type="application/xop+xml"; start="0.urn:uuid:806D8FD2D542EDCC2C1199332890719@apache.org"; start-info="application/soap+xml"; action="urn:ihe:iti:2007:ProvideAndRegisterDocumentSet-b" User-Agent: Axis2 Host: localhost:9085 --MIMEBoundaryurn_uuid_806D8FD2D542EDCC2C1199332890718 Content-Type: application/xop+xml; charset=UTF-8; type="application/soap+xml" Content-Transfer-Encoding: binary Content-ID: <0.urn:uuid:806D8FD2D542EDCC2C1199332890719@apache.org> <?xml version='1.0' encoding='UTF-8'?> <soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope" xmlns:wsa="http://www.w3.org/2005/08/addressing"> <soapenv:Header> <wsa:To>http://localhost:9085/axis2/services/repositoryBonedoc</wsa:To> <wsa:MessageID>urn:uuid:806D8FD2D542EDCC2C1199332890651</wsa:MessageID> <wsa:Action>urn:ihe:iti:2007:ProvideAndRegisterDocumentSet-b</wsa:Action> </soapenv:Header> <soapenv:Body> <xdsb:ProvideAndRegisterDocumentSetRequest xmlns:xdsb="urn:ihe:iti:xds-b:2007"> <lcm:SubmitObjectsRequest xmlns:lcm="urn:oasis:names:tc:ebxml-regrep:xsd:lcm:3.0"> <rim:RegistryObjectList xmlns:rim="urn:oasis:names:tc:ebxml-regrep:xsd:rim:3.0"> <rim:ExtrinsicObject id="Document01" mimeType="text/plain" objectType="urn:uuid:7edca82f-054d-47f2-a032-9b2a5b5186c1"> </rim:ExtrinsicObject> <rim:RegistryPackage id="SubmissionSet01" objectType="urn:oasis:names:tc:ebxml-regrep:ObjectType:RegistryObject:RegistryPackage"> </rim:RegistryPackage> <rim:Association associationType="urn:oasis:names:tc:ebxml-regrep:AssociationType:HasMember" sourceObject="SubmissionSet01" targetObject="Document01" id="ID_12928619_2" objectType="urn:oasis:names:tc:ebxml-regrep:ObjectType:RegistryObject:Association"> <rim:Slot name="SubmissionSetStatus"> <rim:ValueList> <rim:Value>Original</rim:Value> </rim:ValueList> </rim:Slot> </rim:Association> </rim:RegistryObjectList> </lcm:SubmitObjectsRequest> <xdsb:Document id="Document01"> <xop:Include href="cid:1.urn:uuid:806D8FD2D542EDCC2C1199332890776@apache.org" xmlns:xop="http://www.w3.org/2004/08/xop/include"/> </xdsb:Document> </xdsb:ProvideAndRegisterDocumentSetRequest> </soapenv:Body> </soapenv:Envelope> --MIMEBoundaryurn_uuid_806D8FD2D542EDCC2C1199332890718 Content-Type: text/plain Content-Transfer-Encoding: binary Content-ID: <1.urn:uuid:806D8FD2D542EDCC2C1199332890776@apache.org> This is my document. It is great! --MIMEBoundaryurn_uuid_806D8FD2D542EDCC2C1199332890718--
Response
HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Type: application/soap+xml; action="urn:ihe:iti:2007:ProvideAndRegisterDocumentSet-bResponse";charset=UTF-8 Date: Thu, 03 Jan 2008 04:01:37 GMT <?xml version='1.0' encoding='UTF-8'?> <soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope" xmlns:wsa="http://www.w3.org/2005/08/addressing"> <soapenv:Header> <wsa:Action>urn:ihe:iti:2007:ProvideAndRegisterDocumentSet-bResponse</wsa:Action> <wsa:RelatesTo>urn:uuid:806D8FD2D542EDCC2C1199332890651</wsa:RelatesTo> </soapenv:Header> <soapenv:Body> <rs:RegistryResponse xmlns:rs="urn:oasis:names:tc:ebxml-regrep:xsd:rs:3.0" status="urn:oasis:names:tc:ebxml-regrep:ResponseStatusType:Success"/> </soapenv:Body> </soapenv:Envelope>
Example Register Document Set-b transaction
Below is an example request and response from a Register Document Set-b transaction taken from a trace of the Public Registry. The original was chunk encoded (included header Transfer-Encoding: chunked). This encoding has been removed for readability. To make this a valid transaction either the chunked encoding would have to be redone or a Content-Length header would have to be added.
Request
POST /axis2/services/registryBonedoc HTTP/1.1 Content-Type: application/soap+xml; charset=UTF-8; action="urn:ihe:iti:2007:RegisterDocumentSet-b" User-Agent: Axis2 Host: localhost:9085 <?xml version='1.0' encoding='UTF-8'?> <soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope" xmlns:wsa="http://www.w3.org/2005/08/addressing"> <soapenv:Header> <wsa:To>http://localhost:9085/axis2/services/registryBonedoc</wsa:To><wsa:MessageID>urn:uuid:1CF198BACD3697AB7D1203091097442</wsa:MessageID> <wsa:Action>urn:ihe:iti:2007:RegisterDocumentSet-b</wsa:Action> </soapenv:Header> <soapenv:Body> <lcm:SubmitObjectsRequest xmlns:lcm="urn:oasis:names:tc:ebxml-regrep:xsd:lcm:3.0"> <rim:RegistryObjectList xmlns:rim="urn:oasis:names:tc:ebxml-regrep:xsd:rim:3.0"> <rim:ExtrinsicObject id="Document01" mimeType="text/plain" objectType="urn:uuid:7edca82f-054d-47f2-a032-9b2a5b5186c1"/> </rim:RegistryObjectList> </lcm:SubmitObjectsRequest> </soapenv:Body> </soapenv:Envelope>
Response
HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Type: application/soap+xml; action="urn:ihe:iti:2007:RegisterDocumentSet-bResponse";charset=UTF-8 Date: Fri, 15 Feb 2008 15:58:21 GMT <?xml version='1.0' encoding='UTF-8'?> <soapenv:Envelope xmlns:soapenv="http://www.w3.org/2003/05/soap-envelope" xmlns:wsa="http://www.w3.org/2005/08/addressing"> <soapenv:Header> <wsa:Action>urn:ihe:iti:2007:RegisterDocumentSet-bResponse</wsa:Action> <wsa:RelatesTo>urn:uuid:1CF198BACD3697AB7D1203091097442</wsa:RelatesTo> </soapenv:Header> <soapenv:Body> <rs:RegistryResponse xmlns:rs="urn:oasis:names:tc:ebxml-regrep:xsd:rs:3.0" status="urn:oasis:names:tc:ebxml-regrep:ResponseStatusType:Success" /> </soapenv:Body> </soapenv:Envelope>
See Also
Cross Enterprise Document Sharing
Cross-Enterprise Document Sharing Implementation
XDS Stored Query Implementation
Metadata Issues
RegistryObjectList within RegistryPackage
The ebRIM 3.0 Schema allows the nesting of a RegistryObjectList within a RegistryPackage but XDS.b does not and the XDS tools do not recognize this nesting. For now XDS.b accepts XDS.a metadata content but with the ebRIM 3.0 coding requirements (different namespace, extra attributes, sub-element ordering etc.)