XSLT : Add a namespace declaration to the root element

Question

I have this XML document :

<?xml version="1.0" encoding="utf-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi">
    <Fragment>
        <DirectoryRef Id="AcquisitionFolder">
            <Directory Id="dir2EE87E668A6861A2C8B6528214144568" Name="bin" />
            <Directory Id="dir99C9EB95694B90A2CD31AD7E2F4BF7F6" Name="Decoders" />
        </DirectoryRef>
    </Fragment>
</Wix>

I'd like to obtain the following result :

<?xml version="1.0" encoding="utf-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi" xmlns:util="http://schemas.microsoft.com/wix/UtilExtension>
    <Fragment>
        <DirectoryRef Id="AcquisitionFolder">
            <Directory Id="dir2EE87E668A6861A2C8B6528214144568" Name="bin" />
            <Directory Id="dir99C9EB95694B90A2CD31AD7E2F4BF7F6" Name="Decoders" />
        </DirectoryRef>
    </Fragment>
</Wix>

It seems a simple problem, but I didn't find the solution :-( I made several attempts, and found several similar questions (this one for example : XSLT: Add namespace to root element), but they didn't help me.

Thanks for any advice !!!

Answer 1

In many cases, you can simply embed the namespace into the projected Xml elements (including root) as part of a Literal Result Element:

<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    version="1.0">
    <xsl:output method="xml" indent="yes"/>

    <xsl:template match="/*[local-name()='Wix']">
        <Wix xmlns="http://schemas.microsoft.com/wix/2006/wi"
             xmlns:util="http://schemas.microsoft.com/wix/UtilExtension">
            <xsl:copy-of select="node()|@*"/>
        </Wix>
     </xsl:template>
</xsl:stylesheet>

More formally / generally, any namespaces in your output xml can be added into the stylesheet's own declaration (either globally, or using a namespace alias), e.g.

<xsl:stylesheet 
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:wix="http://www.foo.com/2001/v1"
    ...other namespaces here>

... and then referenced in the output

<xsl:template match="/">
    <wix:Wix>
       <wix:Child>
          ...

If there are unwanted / unused namespaces residual in the resultant output (e.g. needed in the source document, but not in the output document), you are able able to clean these out with exclude-result-prefixes