Getting XSLT Current Node, formatted as XPath Query?
Question
I have the following block of code that gets the name of the nodes down the tree, like this:
section/page/subPage
But I would like to be able to get it down to the following (just making it up):
section[@id='someId']/page/subPage[@user='UserA']/@title
I found the following code from one of these StackOverflow posts:
<xsl:attribute name="path">
<xsl:for-each select="ancestor-or-self::*">
<xsl:if test="name() != 'root'">
<xsl:value-of select="name()">
<xsl:if test="not(position()=last())">
<xsl:text>/</xsl:text>
</xsl:if>
</xsl:value-of>
</xsl:if>
</xsl:for-each>
</xsl:attribute>
Which gives me the straight path, but I would like to run more logic on it to make it so it included the @id (or relevant attribute), and maybe some more stuff I can't think of at the moment.
What is the best way to do this?
I've checked into EXSLT functions, which may work, but maybe you guys have already solved this problem a better way.
Any ideas?
I'm using ruby's nokogiri to parse the xml/xslt if that helps.
Thanks a lot, Lance
Solution
This solution does what you want:
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" encoding="utf-8" omit-xml-declaration="yes" />
<xsl:template match="/">
<root>
<xsl:attribute name="path">
<xsl:apply-templates select="(//@title)[1]" mode="make-path" />
</xsl:attribute>
</root>
</xsl:template>
<xsl:template match="*|@*" mode="make-path">
<xsl:apply-templates select="parent::*" mode="make-path" />
<xsl:text>/</xsl:text>
<xsl:apply-templates select="." mode="make-name" />
<xsl:choose>
<xsl:when test="self::section">
<xsl:apply-templates select="@id" mode="make-predicate" />
</xsl:when>
<xsl:when test="self::subPage">
<xsl:apply-templates select="@user" mode="make-predicate" />
</xsl:when>
</xsl:choose>
</xsl:template>
<xsl:template match="*|@*" mode="make-predicate">
<xsl:text>[</xsl:text>
<xsl:apply-templates select="." mode="make-name" />
<xsl:text> = '</xsl:text>
<xsl:value-of select="." />
<xsl:text>']</xsl:text>
</xsl:template>
<xsl:template match="*" mode="make-name">
<xsl:value-of select="name()" />
</xsl:template>
<xsl:template match="@*" mode="make-name">
<xsl:text>@</xsl:text>
<xsl:value-of select="name()" />
</xsl:template>
</xsl:stylesheet>
When applied to
<section id="someId">
<page>
<subPage user="UserA" title="test" />
<subPage user="UserB" title="blah" />
</page>
<page>
<subPage user="UserC" title="fooh" />
</page>
</section>
you get:
<root path="/section[@id = 'someId']/page/subPage[@user = 'UserA']/@title" />
The <xsl:choose>
is the configurable spot (add as many <xsl:when>
s as you like):
<!-- test for element name -->
<xsl:when test="self::section">
<!-- make predicates out of selected attributes -->
<xsl:apply-templates select="@id" mode="make-predicate" />
</xsl:when>
also possible:
<xsl:when test="self::section">
<xsl:apply-templates select="@name|@category|subElement" mode="make-predicate" />
</xsl:when>
which would lead to
<root path="/section[@name = 'someName'][@category = 'somecat'][subElement = 'xyz']/..." />
The only issue I see is with predicate values that contain single quotes. They would break the XPath.
OTHER TIPS
For each ancestor node you can loop over all attributes with simple xsl:for-each
<xsl:for-each select="@*">
You could then use the attributes to build up the XPath string
<xsl:for-each select="ancestor-or-self::*">
<xsl:if test="name() != 'root'">
<xsl:value-of select="name()"/>
<xsl:if test="@*">
<xsl:text>[</xsl:text>
<xsl:for-each select="@*">
<xsl:text>@</xsl:text>
<xsl:value-of select="name()"/>
<xsl:text>='</xsl:text>
<xsl:value-of select="."/>
<xsl:text>'</xsl:text>
<xsl:if test="not(position()=last())">
<xsl:text> and </xsl:text>
</xsl:if>
</xsl:for-each>
<xsl:text>]</xsl:text>
</xsl:if>
<xsl:if test="not(position()=last())">
<xsl:text>/</xsl:text>
</xsl:if>
</xsl:if>
</xsl:for-each>