Hi all.

I am working on implementing a lite export routine from our program to the DDI XML format:
http://www.ddialliance.org/Specification/DDI-Lifecycle/3.1/XMLSchema/

A convinient way of working with the DDI format is to prefix elements using common set of prefix'es, but having spent most of the day trying to I can only make it work with a single prefix.

program project1;
{$mode objfpc}{$H+}
uses
   Classes, DOM, XMLWrite;
var
   XMLDoc: TXMLDocument;
   DDIInstance: TDOMElement;
   Attr: TDOMAttr;
begin
   XMLDoc := TXMLDocument.Create;
   DDIInstance := XMLDoc.CreateElementNS('ddi:instance:3_0', 'DDIInstance');
   DDIInstance.Prefix := 'ns1';        // this gives me:
<ns1:DDIInstance xmlns:ns1="ddi:instance:3_0"> which is great.
   // now I would like to expand with eg: xmlns:a="ddi:archive:3_0"
   Attr := XMLDoc.CreateAttributeNS('ddi:archive:3_0', 'huh');
   Attr.Prefix := 'a';
   DDIInstance.SetAttributeNode(Attr);   // but this gives:
<ns1:DDIInstance xmlns:ns1="ddi:instance:3_0" xmlns:a="ddi:archive:3_0"
a:huh=""/>
   Xmldoc.AppendChild(DDIInstance);
   WriteXMLFile(XMLDOc, '/tmp/test.xml');
end.

How can i get the "xmlns:a="ddi:archive:3_0" without the additional attribute AND maintain the namespace + prefix in later elements?

Kind regards,
Torsten Bonde Christiansen.

Torsten Bonde Christiansen wrote

How can i get the "xmlns:a="ddi:archive:3_0" without the additional attribute AND maintain the namespace + prefix in later elements?

Hi.

It's hard to test without a (small please) comlete XML example because the NS attribute is added when it's needed. So, you need to add an attribute or a child element that uses the Namespace.

The XML below is created with the modfied program ahead. But I believe a method to create a namespace attribute would be useful.

<?xml version="1.0" encoding="utf-8"?>
<ns1:DDIInstance xmlns:ns1="ddi:instance:3_0">
<a:AnAELement xmlns:a="ddi:archive:3_0">
<a:AnotherAELement a:MyAtt="A value"/>
</a:AnAELement>
</ns1:DDIInstance>

program project1;
{$mode objfpc}{$H+}
uses
 Classes, DOM, XMLWrite;
const
     cArchive = 'ddi:archive:3_0';
var
 XMLDoc: TXMLDocument;
 DDIInstance: TDOMElement;
 AnAElement, AnotherAElement: TDOMElement;
begin
 XMLDoc := TXMLDocument.Create;
 DDIInstance := XMLDoc.CreateElementNS('ddi:instance:3_0', 'DDIInstance');
 DDIInstance.Prefix := 'ns1';        // this gives me:
<ns1:DDIInstance xmlns:ns1="ddi:instance:3_0"> which is great.
 //Here a New element using the Namespace that will be created.
 AnAElement:=XMLDoc.CreateElementNS(cArchive, 'a:AnAELement');
 DDIInstance.AppendChild(AnAElement);
 //Another element of the same namespace, child of the prior, no
Namespace creation
 //needed
 AnotherAElement:=XMLDoc.CreateElementNS(cArchive, 'a:AnotherAELement');
 AnAElement.AppendChild(AnotherAElement);
 //The same as above, but with an Attribute
 AnotherAElement.SetAttributeNS(cArchive, 'a:MyAtt', 'A value');
 Xmldoc.AppendChild(DDIInstance);
 WriteXMLFile(XMLDOc, '/tmp/test.xml');
end.

I have created a bug report[1] with an example of malformed file.

[1] http://bugs.freepascal.org/view.php?id=22299

I believe that the solution(given by Sergei Gorelkin at [1]) is:

DDIInstance.SetAttributeNS('ddi:archive:3_0','xmlns:a','ddi:archive:3_0');

[1] http://bugs.freepascal.org/view.php?id=22299#c60652

Great - thank you very much!

-Torsten.