How to escape greater than and less than sign on all the child elements of a particular element in XML using XSL?

Question

I am new to XML and XSL. I have got a requirement write an XSL script to replace the greater than (>) and less than (<) sign of some child elements with the escape strings. I need to perform the replace on the child elements within the "startupXml" element (see code below)

<?xml version="1.0" encoding="utf-8" ?>
<s:Envelope  xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xmlns:xsd="http://www.w3.org/2001/XMLSchema">
        <Startup2 xmlns="http://keyfax.touch-base.com/">
            <startupXml>
                <KeyfaxData>
                    <Startup>
                        <Config>Test</Config>
                        <Mode>RD</Mode>
                        <UserName>JBLOG</UserName>
                        <PropertyType>P</PropertyType>
                        <PropertyID>L0000</PropertyID>
                        <ReferenceID>12345</ReferenceID>
                        <Property>
                            <ContactHistory/>
                        </Property>
                    </Startup>
                </KeyfaxData>
            </startupXml>
        </Startup2>
    </s:Body>
</s:Envelope>

The result should look like this:

<?xml version="1.0" encoding="utf-8" ?>
<s:Envelope  xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xmlns:xsd="http://www.w3.org/2001/XMLSchema">
        <Startup2 xmlns="http://keyfax.touch-base.com/">
            <startupXml>
                &lt;KeyfaxData&gt;
                    &lt;Startup&gt;
                        &lt;Config&gt;Test&lt;/Config&gt;
                        &lt;Mode&gt;RD&lt;/Mode&gt;
                        &lt;UserName&gt;JBLOG&lt;/UserName&gt;
                        &lt;PropertyType&gt;P&lt;/PropertyType&gt;
                        &lt;PropertyID&gt;L0000&lt;/PropertyID&gt;
                        &lt;ReferenceID&gt;12345&lt;/ReferenceID&gt;
                        &lt;Property&gt;
                            &lt;ContactHistory/&gt;
                        &lt;/Property&gt;
                    &gt;/Startup&lt;
                &gt;/KeyfaxData&lt;
            </startupXml>
        </Startup2>
    </s:Body>
</s:Envelope>

I've tried some xsl scripts to find and replace, but as I am new to XML and XSL, the outcome was not successful. Could someone point me in the correct direction please.

Thanks in advance.

Answer 1

In this general case (escaping all descendant elements of a particular input element), you could use

XSLT Stylesheet (online)

<?xml version="1.0" encoding="UTF-8" ?>
<xsl:transform xmlns:xsl="http://www.w3.org/1999/XSL/Transform" version="2.0"
    xmlns:kf="http://keyfax.touch-base.com/">
    <xsl:output method="xml" omit-xml-declaration="no" encoding="UTF-8" indent="yes" />

    <xsl:template match="@*|node()">
        <xsl:copy>
            <xsl:apply-templates select="@*|node()"/>
        </xsl:copy>
    </xsl:template>

    <xsl:template match="kf:startupXml//*">
        <xsl:value-of select="concat('&lt;',name(),'&gt;')"/>
            <xsl:apply-templates/>
        <xsl:value-of select="concat('&lt;/',name(),'&gt;')"/>
    </xsl:template>

</xsl:transform>

XML Output

Your expected output immediately closes the ContactHistory element: <Contact History/>, but that would require additional logic.

<?xml version="1.0" encoding="UTF-8"?>
<s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/">
    <s:Body xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
           xmlns:xsd="http://www.w3.org/2001/XMLSchema">
        <Startup2 xmlns="http://keyfax.touch-base.com/">
            <startupXml>
                &lt;KeyfaxData&gt;
                    &lt;Startup&gt;
                        &lt;Config&gt;Test&lt;/Config&gt;
                        &lt;Mode&gt;RD&lt;/Mode&gt;
                        &lt;UserName&gt;JBLOG&lt;/UserName&gt;
                        &lt;PropertyType&gt;P&lt;/PropertyType&gt;
                        &lt;PropertyID&gt;L0000&lt;/PropertyID&gt;
                        &lt;ReferenceID&gt;12345&lt;/ReferenceID&gt;
                        &lt;Property&gt;
                            &lt;ContactHistory&gt;&lt;/ContactHistory&gt;
                        &lt;/Property&gt;
                    &lt;/Startup&gt;
                &lt;/KeyfaxData&gt;
            </startupXml>
        </Startup2>
    </s:Body>
</s:Envelope>

Answer 2

The main thing you need to bear in mind is that XSLT doesn't see the markup, it sees the tree of nodes formed by parsing the markup. So you need a template rule something like this:

<xsl:template match="*" mode="escape-markup">
  <xsl:text>&lt;</xsl:text>
  <xsl:value-of select="name()"/>
  <xsl:text>&gt;</xsl:text>
  <xsl:apply-templates mode="#current"/>
  <xsl:text>&lt;/</xsl:text>
  <xsl:value-of select="name()"/>
  <xsl:text>&gt;</xsl:text>
</xsl:template>

which you then invoke when you hit the relevant element:

<xsl:template match="startUpXml">
  <xsl:apply-templates mode="escape-markup"/>
</xsl:template>

It gets a little more complicated if you have to handle attributes and namespaces.