xslt - Output entire XML as an attribute

Question

I'm fairly new to XML and XSL Stylesheets, and I've been tasked with creating a stylesheet for one of our clients. I have already created a stylesheet that outputs an XML in the following format:

<Trip TripType="Normal">
    <Plan BeginTime="2011-08-13T10:00:00" UserDefinedTripID="777" UserDefinedRouteID="777">
        <PlanStop ArrivalTime="2011-08-13T15:30:00" ArrivalLock="true" SiteID="1" PassThru1="test1" PassThru2="test2" PassThru3="test3" PassThru4="test4">
            <PlanNote Line1="Freeform Text" Line2="Line2" Line3="Line3" />
            <PlanCargo Duration="60" BillID="" Weight="100" Units="100.0" XUnitTypeID="10" Action="Pick" />
            <PlanNote Line1="Freeform Text" Line2="Line2" Line3="Line3" />
            <PlanCargo Duration="60" BillID="" Weight="100" Units="100.0" XUnitTypeID="12" Action="Pick" />
        </PlanStop>
    </Plan>
</Trip>

I need to take the output and insert the contents into an attribute within the Trip element to look like this:

<Trip TripID="-1" CurrentRevisionNumber="1" IsDispatch="1" IsActive="0" 
IsComplete="0" OrganizationID="4"
TripData="&lt;Trip TripType=&quot;Normal&quot;&gt;
  &lt;Plan BeginTime=&quot;2011-08-13T10:00:00&quot; UserDefinedTripID=&quot;777&quot;
  UserDefinedRouteID=&quot;777&quot;&gt;
    &lt;PlanStop ArrivalTime=&quot;2011-08-13T10:00:00&quot; ArrivalLock=&    quot;true&quot; SiteID=&quot;1&quot; PassThru1=&quot;test1&quot; PassThru2=&    quot;test2&quot; PassThru3=&quot;test3&quot; PassThru4=&quot;test4&quot;&gt;
    &lt;PlanCargo Duration=&quot;45&quot; BillID=&quot;&quot; Weight=&    quot;100&quot; Units=&quot;100.0&quot; XUnitTypeID=&quot;9&quot; Action=&quot;Pick&quot;     /&gt;
    &lt;/PlanStop&gt; />

So in other words, I need to take an existing XML output and put it in an attribute while performing some character transformations.

Yes, it is extremely ugly, but this is how they want it. I was thinking of making another XSL that will copy over the XML output from the original XSL transformation and place it in an attribute while converting <, >, ", etc into < , > , " , etc (not sure what they're called).

I've scoured the internet for solutions, but I can't seem to find any that are quite like this (I'd imagine that's because this is a ridiculous request). I can provide my original XSL if necessary, but I'd rather not change it, if possible.

Thanks in advance!

Answer 1

I have to agree with other commenters, that inserting an XML document as lexical XML within an attribute is completely nutty. The owners of the data will lose so much power and flexibility and gain nothing in return. However, if you really have no choice, then commit suicide (joke). If this option is unpalatable for you, then you could serialise your inner XML with templates like so ...

<xsl:template match="*" mode="serialise">
  <xsl:value-of select="concat('&lt;',local-name(),' ')">
  <xsl:apply-templates select="@*" mode="serialise">
  <xsl:value-of select="' &gt;'">
  <xsl:apply-templates select="*|text()" mode="serialise">
  <xsl:value-of select="concat('&lt;/',local-name(),' &gt;')">
</xsl:template>

<xsl:template match="@*" mode="serialise">
  <xsl:value-of select="concat(local-name(),'=&quot;',.,'&quot; ')">
</xsl:template>

<xsl:template match="text()" mode="serialise">
  <xsl:value-of select=".">
</xsl:template>

Take the root element of the inner structure that you want to encoded as lexical XML and invoke <xsl:apply-templates> with @mode="serialise". Capture the output of this invocation into a string variable. You can then insert the contents of the string variable in what-ever attribute in the result tree you like.

Caveat

These simple templates do not process comments(), processing-instructions() and DocTypes. Also, as per XDM (contrary to DOM), adjacent text type nodes (text, CDATA, character references etc.) will be merged. Also this does not work with namespaces.