Re: [xsl] How to output the unused namespaces in the XML document?

[Evan Lenz <evan@xxxxxxxxxxxx>]

Your solution includes a lot of repeat messages. You also don't check 
for whether attributes use the namespace. Here's one that avoids both 
problems:

<xsl:template match="/">
 <xsl:for-each select="//namespace::*[not(. = 
(preceding::*|../ancestor::*)/namespace::*)]">
   <xsl:if test="not((//* | //@*)[namespace-uri(.) = current()])">
This namespace is unused: <xsl:value-of select="."/>
   </xsl:if>
 </xsl:for-each>
</xsl:template>


Things are much easier in XSLT/XPath 2.0 (assuming current() bound to 
document node):

distinct-values(//namespace::*)[not(. = 
(current()//*|current()//@*)/namespace-uri(.))]

Neither of our solutions checks for unused prefixes, e.g., if the 
document had multiple declarations for the same URI but uses only one of 
the prefixes on element/attribute names. That could be done in XSLT 2.0, 
but whether or not it would work in XSLT 1.0 is dependent on how your 
processor implements name(). (XPath 2.0 provides direct access to what 
prefix was used, but XPath 1.0 does not.)

Keep in mind that the above tests don't guarantee that the namespace 
isn't "used." If your input document is XSLT, XSD, or any other 
vocabulary that uses QNames in content, you can't safely assume the 
namespace isn't being used.

Evan

--
Evan Lenz
Lenz Consulting Group, Inc.
http://lenzconsulting.com
+1 (360) 297-0087



Costello, Roger L. wrote:
> Hi Folks,
>
> Consider this XML document:
>
> <?xml version="1.0"?>
> <N1:NumberList xmlns:N1="http://www.example1.org";
>                xmlns:N2="http://www.example2.org";>
>         <Number>23</Number>
>         <Number>41</Number>
>         <Number xmlns:N3="http://www.example3.org";>70</Number>
>         <Number>103</Number>
>         <Number>99</Number>
>         <Number>6</Number>
> </N1:NumberList>
>
> Notice that there are three (3) namespaces, but two of them are unused:
>
>     http://www.example2.org
>  
>     http://www.example3.org
>
> I want an XSLT transform that will output all the unused namespaces in the input XML document. 
>
> Here's the solution I came up with:
>
>
>     <xsl:template match="*">
>         <xsl:variable name="elem" select="." />
>         <xsl:for-each select="namespace::*[. != 'http://www.w3.org/XML/1998/namespace']">
>             <xsl:variable name="ns" select="." />
>             <xsl:if test="not($elem/ancestor::*[namespace::* = $ns])">
>                 <xsl:if test="not($elem/descendant-or-self::*[namespace-uri() = $ns])"> 
>                     This namespace is unused: <xsl:value-of select="$ns" />
>                 </xsl:if>
>             </xsl:if>
>         </xsl:for-each>
>         <xsl:apply-templates select="*" />
>     </xsl:template>
>
>
> Is there a better solution? (I am using XSLT 1.0)
>
> /Roger