Doing a double-pass in XSL? - xslt

Is it possible to store the output of an XSL transformation in some sort of variable and then perform an additional transformation on the variable's contents? (All in one XSL file)
(XSLT-2.0 Preferred)

XSLT 2.0 Solution :
<xsl:variable name="firstPassResult">
<xsl:apply-templates select="/" mode="firstPass"/>
</xsl:variable>
<xsl:template match="/">
<xsl:apply-templates select="$firstPassResult" mode="secondPass"/>
</xsl:template>
The trick here, is to use mode="firstPassResult" for the first pass while all the templates for the sedond pass should have mode="secondPass".
Edit:
Example :
<root>
<a>Init</a>
</root>
<xsl:stylesheet version="2.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output indent="yes"/>
<xsl:strip-space elements="*"/>
<xsl:variable name="firstPassResult">
<xsl:apply-templates select="/" mode="firstPass"/>
</xsl:variable>
<xsl:template match="/" mode="firstPass">
<test>
<firstPass>
<xsl:value-of select="root/a"/>
</firstPass>
</test>
</xsl:template>
<xsl:template match="/">
<xsl:apply-templates select="$firstPassResult" mode="secondPass"/>
</xsl:template>
<xsl:template match="/" mode="secondPass">
<xsl:message terminate="no">
<xsl:copy-of select="."/>
</xsl:message>
</xsl:template>
</xsl:stylesheet>
Output :
[xslt] <test><firstPass>Init</firstPass></test>
So the first pass creates some elements with the content of root/a and the second one prints the created elements to std out. Hopefully this is enough to get you going.

Yes, with XSLT 2.0 it is easy. With XSLT 1.0 you can of course also use modes and store a temporary result in a variable the same way as in XSLT 2.0 but the variable is then a result tree fragment, to be able to process it further with apply-templates you need to use an extension function like exsl:node-set on the variable.

Related

XSLT 3.0 Dynamic select with variable in apply-templates?

I want to apply templates to a set of nodes where part of the select path is a variable. I'm using Saxon-HE 9.8 (awesome lib!)
I'm trying to achieve the following
<variable name="x" select="string('baz')"/>
<xsl:apply-templates select="foo/bar/$x"/>
This doesn't seem to work. Is there a syntax that will allow me to dynamically construct the select XPath for this apply-templates instruction? Or, is there another technique for dynamically achieving this effect? I even tried pushing this down to my <xsl:template match=foo/bar/$x> but no luck.
My motivation here is in my application the variable value is coming from a separate configuration file. Based on the configuration I need to run templates matching specific path segments driven by config strings...
If your variables are always going to be a simple string value expressing the name of an element, then one option would be to match a little more generically on an element and then use the string variable in a predicate to filter for a match of the element name:
<xsl:apply-templates select="foo/bar/*[local-name() = $x]"/>
With Saxon-PE or Saxon-EE, you could leverage xsl:evaluate and do something like this:
<xsl:variable name="var" as="node()*">
<xsl:evaluate xpath="concat('foo/bar/',$x)" context-item="."/>
</xsl:variable>
<xsl:apply-templates select="$var"/>
If you declare a static parameter <xsl:param name="x" static="yes" as="xs:string" select="'baz'"/> for the value and then use a shadow attribute in the form of _select="foo/bar/{$x}" you can even construct the path dynamically, but only when compiling the XSLT.
In a static parameter you can of course pull in a configuration file and use values from it:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
version="3.0">
<xsl:param name="config-uri" static="yes" as="xs:string" select="'https://martin-honnen.github.io/xslt/2018/config-example1.xml'"/>
<xsl:param name="config-doc" static="yes" as="document-node()" select="doc($config-uri)"/>
<xsl:mode on-no-match="shallow-copy"/>
<xsl:template match="item[#type = 'foo']">
<xsl:copy>
<xsl:value-of _select="{$config-doc/map/from[#key = 'foo']}"/>
</xsl:copy>
</xsl:template>
<xsl:template match="item[#type = 'bar']">
<xsl:copy>
<xsl:value-of _select="{$config-doc/map/from[#key = 'bar']}"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
https://xsltfiddle.liberty-development.net/6qVRKvX/1
Another option I didn't mention in my first answer but that is also a viable way with Saxon 9.8 or any other XSLT 3 processor is the use of XSLT to create XSLT and then to use the transform function (https://www.w3.org/TR/xpath-functions/#func-transform) to run that generated XSLT. That approach has the advantage that it works with Saxon 9.8 HE where xsl:evaluate is not supported:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xs="http://www.w3.org/2001/XMLSchema"
xmlns:axsl="http://www.w3.org/1999/XSL/Transform-alias"
exclude-result-prefixes="axsl"
version="3.0">
<xsl:param name="config-uri" as="xs:string" select="'https://martin-honnen.github.io/xslt/2018/config-example1.xml'"/>
<xsl:param name="config-doc" as="document-node()" select="doc($config-uri)"/>
<xsl:namespace-alias stylesheet-prefix="axsl" result-prefix="xsl"/>
<xsl:variable name="generated-xslt">
<axsl:stylesheet version="3.0">
<axsl:mode on-no-match="shallow-copy"/>
<xsl:for-each select="$config-doc/map/from">
<axsl:template match="item[#type = '{#key}']">
<axsl:copy>
<axsl:value-of select="{.}"/>
</axsl:copy>
</axsl:template>
</xsl:for-each>
</axsl:stylesheet>
</xsl:variable>
<xsl:mode on-no-match="shallow-copy"/>
<xsl:template match="/">
<xsl:sequence
select="transform(map {
'source-node' : .,
'stylesheet-node' : $generated-xslt
})?output"/>
</xsl:template>
</xsl:stylesheet>
https://xsltfiddle.liberty-development.net/6qVRKvX/2

I'm unable to get the desired values in my XSLT

This is the input :
<Data>
<A_ID>123456789</A_ID>
<A_Code>ojhgf</A_Code>
<A_Rec>
<inner1>2345</inner1>
<inner2>14April</inner2>
<inner3>15November</inner3>
</A_Rec>
</Data>
This is my XSLT:
<xsl:variable name="AID" select="A_ID" />
<xsl:variable name="ACode" select="A_Code" />
<xsl:for-each xmlns:sch="http://schemas.w3.com/" select="//A_Rec">
<sch:COMPANY>
<xsl:value-of select="$AID" />
</sch:COMPANY>
<sch:COMPANY_CODE>
<xsl:value-of select="$ACode" />
</sch:COMPANY_CODE>
</xsl:for-each>
I am trying to get the value "123456789" in the below mentioned line. $AID should hold 123456789, i am getting the desired value outside the for-each loop though.
But I’m not getting AID and ACode values inside the for-each loop for Company and company code. What do I do?
You should be using "Data/A_ID". Assuming that your context node is not "Data" as I see nothing else wrong.
Once created, XSLT variables cannot change their value.
There's a very good SO answer here that may help you redesign your XSLT.
Edit: Lingamurthy CS has correctly identified an issue with your XPath, but take a look at the SO page I've linked as it still might be useful.
It seems you want to output A_ID and A_Code in a different node with a different namespace.
Try this instead:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
version="1.0">
<xsl:strip-space elements="*"/>
<xsl:output indent="yes"/>
<xsl:template match="/">
<root xmlns:sch="http://schemas.w3.com/">
<xsl:apply-templates select="Data/A_ID|Data/A_Code"/>
</root>
</xsl:template>
<xsl:template match="Data/A_ID">
<xsl:element name="sch:COMPANY" namespace="http://schemas.w3.com/">
<xsl:value-of select="."/>
</xsl:element>
</xsl:template>
<xsl:template match="Data/A_Code">
<xsl:element name="sch:COMPANY_CODE" namespace="http://schemas.w3.com/">
<xsl:value-of select="."/>
</xsl:element>
</xsl:template>
</xsl:stylesheet>

xsl transformation to sort output at the end of traversal

what is the actual best way to transform this
<root>
<data/>
<data/>
</root>
into this:
<data1/>
<data1/>
<data2/>
<data2/>
Somehow the way xslt engine works let me think it can only produce this:
<data1/>
<data2/>
<data1/>
<data2/>
which is produced by this simple sheet:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes"/>
<xsl:template match="data">
<xsl:element name="data1"/>
<xsl:element name="data2"/>
</xsl:template>
</xsl:stylesheet>
is it possible to do some kind of reordering at the end of transformation (without using a second application) ?
You have to use two separate templates to create the data1 and data2 elements. Then you can apply these templates from a template matching the root node, for example. The mode attribute of xsl:template is also useful in this case:
<xsl:template match="/">
<xsl:apply-templates select="//data" mode="data1"/>
<xsl:apply-templates select="//data" mode="data2"/>
</xsl:template>
<xsl:template match="data" mode="data1">
<xsl:element name="data1"/>
</xsl:template>
<xsl:template match="data" mode="data2">
<xsl:element name="data2"/>
</xsl:template>
If you only want to add elements like in your example stylesheet but in different order you can do it somewhat like this.
<xsl:template match="/">
<!-- adding data1 for every data tag-->
<xsl:for-each select="//data" >
<xsl:element name="data1"/>
</xsl:for-each>
<!-- adding data2 for every data tag-->
<xsl:for-each select="//data" >
<xsl:element name="data2"/>
</xsl:for-each>
</xsl:template>

XSLT: Add namespace to root element

I need to change namespaces in the root element as follows:
input document:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<foo xsi:schemaLocation="urn:isbn:1-931666-22-9 http://www.loc.gov/ead/ead.xsd"
xmlns:ns2="http://www.w3.org/1999/xlink" xmlns="urn:isbn:1-931666-22-9"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
desired output:
<foo audience="external" xsi:schemaLocation="urn:isbn:1-931666-22-9
http://www.loc.gov/ead/ead.xsd" xmlns:xsi="http://www.w3.org/2001/XMLSchema-
instance" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="urn:isbn:1-931666-22-9">
I was trying to do it as I copy over the whole document and before I give any other transformation instructions, but the following doesn't work:
<xsl:template match="* | processing-instruction() | comment()">
<xsl:copy copy-namespaces="no">
<xsl:for-each select=".">
<xsl:attribute name="audience" select="'external'"/>
<xsl:namespace name="xlink" select="'http://www.w3.org/1999/xlink'"/>
</xsl:for-each>
<xsl:copy-of select="#*"/>
<xsl:apply-templates/>
</xsl:copy>
</xsl:template>
Thanks for any advice!
XSLT 2.0 isn't necessary to solve this problem.
Here is an XSLT 1.0 solution, which works equally well as XSLT 2.0 (just change the version attribute to 2.0):
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:xlink="http://www.w3.org/1999/xlink"
exclude-result-prefixes="xlink"
>
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:template match="node()|#*">
<xsl:copy>
<xsl:apply-templates select="node()|#*"/>
</xsl:copy>
</xsl:template>
<xsl:template match="/*">
<xsl:element name="{name()}" namespace="{namespace-uri()}">
<xsl:copy-of select=
"namespace::*
[not(name()='ns2')
and
not(name()='')
]"/>
<xsl:copy-of select=
"document('')/*/namespace::*[name()='xlink']"/>
<xsl:copy-of select="#*"/>
<xsl:attribute name="audience">external</xsl:attribute>
</xsl:element>
</xsl:template>
</xsl:stylesheet>
When the above transformation is applied on this XML document:
<foo
xsi:schemaLocation="urn:isbn:1-931666-22-9 http://www.loc.gov/ead/ead.xsd"
xmlns:ns2="http://www.w3.org/1999/xlink"
xmlns="urn:isbn:1-931666-22-9"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"/>
the wanted result is produced:
<foo xmlns="urn:isbn:1-931666-22-9"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:xlink="http://www.w3.org/1999/xlink"
xsi:schemaLocation="urn:isbn:1-931666-22-9 http://www.loc.gov/ead/ead.xsd"
audience="external"/>
You should really be using the "identity template" for this, and you should always have it on hand. Create an XSLT with that template, call it "identity.xslt", then into the current XSLT. Assume the prefix "bad" for the namespace you want to replace, and "good" for the one you want to replace it with, then all you need is a template like this (I'm at work, so forgive the formatting; I'll get back to this when I'm at home): ... If that doesn't work in XSLT 1.0, use a match expression like "*[namespace-uri() = 'urn:bad-namespace'", and follow Dimitre's instructions for creating a new element programmatically. Within , you really need to just apply-template recursively...but really, read up on the identity template.

Can an XSLT processor preserve empty CDATA sections?

I'm processing an XML document (an InstallAnywhere .iap_xml installer) before handing it off to another tool (InstallAnywhere itself) to update some values. However, it appears that the XSLT transform I am using is stripping CDATA sections (which appear to be significant to InstallAnywhere) from the document.
I'm using Ant 1.7.0, JDK 1.6.0_16, and a stylesheet based on the identity:
<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="1.0">
<xsl:output method="xml" encoding="UTF-8" cdata-section-elements="string" />
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
Basically, "string" nodes that look like:
<string><![CDATA[]]></string>
are being processed into:
<string/>
From reading XSLT FAQs, I can see that what is happening is legal as far as the XSLT spec is concerned. Is there any way I can prevent this from happening and convince the XSLT processor to emit the CDATA section?
Found a solution:
<xsl:template match="string">
<xsl:element name="string">
<xsl:text disable-output-escaping="yes"><![CDATA[</xsl:text><xsl:value-of select="text()" disable-output-escaping="yes" /><xsl:text disable-output-escaping="yes">]]></xsl:text>
</xsl:element>
</xsl:template>
I also removed the cdata-section-elements attribute from the <xsl:output> element.
Basically, since the CDATA sections are significant to the next tool in the chain, I take output them manually.
To do this, you'll need to add a special case for empty string elements and use disable-output-escaping. I don't have a copy of Ant to test with, but the following template worked for me with libxml's xsltproc, which exhibits the same behavior you describe:
<?xml version="1.0" encoding="UTF-8"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output method="xml" indent="yes" omit-xml-declaration="yes" cdata-section-elements="string"/>
<xsl:template match="string">
<xsl:choose>
<xsl:when test=". = ''">
<string>
<xsl:text disable-output-escaping="yes"><![CDATA[]]></xsl:text>
</string>
</xsl:when>
<xsl:otherwise>
<xsl:copy-of select="."/>
</xsl:otherwise>
</xsl:choose>
</xsl:template>
<xsl:template match="#*|node()">
<xsl:copy>
<xsl:apply-templates select="#*|node()"/>
</xsl:copy>
</xsl:template>
</xsl:stylesheet>
Input:
<input>
<string><![CDATA[foo]]></string>
<string><![CDATA[]]></string>
</input>
Output:
<input>
<string><![CDATA[foo]]></string>
<string><![CDATA[]]></string>
</input>
Once the XML parser has finished with the XML, there is absolutely no difference between <![CDATA[abc]]> and abc. And the same is true for an empty string - <![CDATA[]]> resolves to nothing at all, and is silently ignored. It has no representation in the XML model. In fact, there is no way to tell the difference from CDATA and regular strings, and neither has any representation in the XML model.
Sorry.
Now, why would you want this? Perhaps there is another solution which can help you?