add jsonx conent's checksum to http response

gistfile1.xml

<?xml version="1.0"?>
<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:json="http://www.ibm.com/xmlns/prod/2009/jsonx"
    xmlns:dp="http://www.datapower.com/extensions" extension-element-prefixes="dp">
    <xsl:output method="text"/>
    <xsl:template match="/">      
        <xsl:variable
            name="theMasterNode"
            select="/json:object">
        </xsl:variable>       
        <xsl:variable name="digest">
            <xsl:value-of select="dp:c14n-hash($theMasterNode, false())"/>
        </xsl:variable>       
        <dp:set-http-response-header name="’checksum" value="digest"/>        
    </xsl:template>
</xsl:stylesheet>