XSLT Navigation of Base64-Encoded XML - xslt

Question

I am using XSLT to transform a SOAP response. The XML response has one node encoded in Base64. If we decode this node, it becomes XML text, and I need to perform additional operations on the XML decoded from the Base64.
I would like to do the entire transformation and decoding within the XSLT transform.
The XML response looks something like this:
<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope">
<env:Header/>
<env:Body>
<ns2:runReportResponse
xmlns:ns2="http://xmlns.oracle.com/oxp/service/PublicReportService">
<ns2:runReportReturn>
<ns2:reportBytes>PD94bWwgdmVyc2lvbj0iMS4wIiBlbmNvZGluZz0iVVRGLTgiPz4KPCEtLUdl
bmVyYXRlZCBieSBP
cmFjbGUgQkkgUHVibGlzaGVyIC1EYXRhZW5naW5lLCBkYXRhbW9kZWw6X0N1c3RvbV9TdXBwbHlf
Q2hhaW5fTWFuYWdlbWVudF9JbnZlbnRvcnlfTWFuYWdlbWVudF9JdGVtX1ZlbnR1cmVmb3J0aF94
I can succssfully call
select="sunBase64:base64Decode($base64Value)"
to decode the Base64 node in a
<xsl:variable or <xsl:value-of
tag, but I ultimately want to perform additional operations on the XML decoded from Base64, such as the following:
<xsl:for-each select
on the variable that was defined by calling base64Decode of com.sun.jersey.core.util.Base64.
The Base64 node can be decoded successfully, and the output looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<!--Generated by Oracle BI Publisher -Dataengine,
datamodel:_Custom_Supply_Chain_Management_Inventory_Management_Item_xdm -->
<DATA_DS><P_ORGANIZATION_ID>300000002559348</P_ORGANIZATION_ID>
<G_1>
<ORGANIZATION_NAME>Inventory Organization</ORGANIZATION_NAME>
<ORGANIZATIONID>300000002559348</ORGANIZATIONID>
<ITEMDESCRIPTION>LUBRICANT|MACHINE LUBE|ML-514|AUTOMOTIVE GEAR OIL||EXTREME
PRESSURE|55 GAL/400 LB DRUM|85W-140 VISC|||||||||</ITEMDESCRIPTION>
<ITEMNUMBER>527293318</ITEMNUMBER><PRIMARYUOMVALUE>DR</PRIMARYUOMVALUE>
<ITEM_ID>300000009810631</ITEM_ID>
</G_1>
As I mentioned earlier, I want to use
<xsl:for-each select="$xmlReportBytes/DATA_DS" >
But when I try to run this operation, I get an error in the Java program
that is running the XSLT transformation. Without the /DATA_DS,this
operation runs fine, but I need to navigate into the XML that was
originally encoded in Base64.
How can I resolve this error, or is there an alternative solution? I would like to do all of the operations within XSLT.

Answer 1

If you use an XSLT 3.0 processor with support for the EXPath Binary module then you can decode the base64 text using the bin:decode-string() function (see http://expath.org/spec/binary#decode-string) and then you can parse the resulting XML using the fn:parse-xml() function.
Without these functions, you'll need to call vendor-specific extension functions, and it then depends entirely on what XSLT processor you are using.
You can get these functions if you use Saxon-PE or Saxon-EE.
Note that decoding base64 produces a stream of octets, and to decode these octets as text you need to know the encoding of the text, e.g. iso-8859-1 or utf-8.