Hi everybody,
I just run into a very interesting behavior of XSP (I guess this would also apply to any XSLT transformation). It temporarily ( XSLT seem to do it permanently ) removes name spaces from the files. To be more specific, the name spaces are not there when SAX events occur, but they appear when the document is serialized.
Name spaces are pretty important, so take a look at this example:
PIPELINES - There are three pattern that do the same thing - they generate and serialize SAX events. Nothing more, dead simple
<map:pipeline>
<!-- XSP -->
<map:match pattern="simple-xsp">
<map:generate type="serverpages" src="simple-query.xsp"/>
<map:transform type="log">
<map:parameter name="logfile" value="simple-xsp.txt"/>
<map:parameter name="append" value="no"/>
</map:transform>
<map:serialize type="xml"/>
</map:match><!-- FILE --> <map:match pattern="simple-file">
<map:generate src="simple-query.xml"/>
<map:transform type="log">
<map:parameter name="logfile" value="simple-file.txt"/>
<map:parameter name="append" value="no"/>
</map:transform>
<map:serialize type="xml"/>
</map:match>
<!-- JX --> <map:match pattern="simple-jx">
<map:generate type="jx" src="simple-query.jx">
<map:parameter name="ref" value="true"/>
</map:generate>
<map:transform type="log">
<map:parameter name="logfile" value="simple-jx.txt"/>
<map:parameter name="append" value="no"/>
</map:transform>
<map:serialize type="xml"/>
</map:match>
</map:pipeline>
Now, let's take a closer look at each of those patterns.
XSP
Simple-query.xsp - this could not be any simpler. Generates 2 XML tags - <page><topicRef/></page>
<?xml version="1.0"?>
<xsp:page language="java" xmlns:xsp="http://apache.org/xsp"; xmlns:db="http://apache.org/cocoon/xmldb/1.0";>
<xsp:logic>
String baseName = new String("Test");
</xsp:logic>
<page>
<topicRef xlink:href="#text" xmlns:xlink="http://www.w3.org/1999/xlink";><xsp:expr>baseName</xsp:expr></topicRef>
</page>
</xsp:page>
The output produced is the following (exactly as expected, but keep on reading it will get more interesting at the end):
<?xml version="1.0" encoding="ISO-8859-1"?>
<page xmlns:xsp="http://apache.org/xsp"; xmlns:db="http://apache.org/cocoon/xmldb/1.0";>
<topicRef xlink:href="#text" xmlns:xlink="http://www.w3.org/1999/xlink";>Test</topicRef>
</page>
FILE
Simple-query.xml - Again, an extremely simple XML file that we read and serialize:
<?xml version="1.0" encoding="ISO-8859-1"?>
<page xmlns:xsp="http://apache.org/xsp"; xmlns:db="http://apache.org/cocoon/xmldb/1.0";>
<topicRef xlink:href="#text" xmlns:xlink="http://www.w3.org/1999/xlink";>Test</topicRef>
</page>
Output of the "simple-file" pipeline is this:
<?xml version="1.0" encoding="ISO-8859-1"?>
<page xmlns:xsp="http://apache.org/xsp"; xmlns:db="http://apache.org/cocoon/xmldb/1.0";>
<topicRef xlink:href="#text" xmlns:xlink="http://www.w3.org/1999/xlink";>Test</topicRef>
</page>
JX
Simple-file.jx - Almost identical to Simple-query.xml, with the only difference that text of the topicRef is generated from the request parameters.
<?xml version="1.0" encoding="ISO-8859-1"?>
<page xmlns:xsp="http://apache.org/xsp"; xmlns:db="http://apache.org/cocoon/xmldb/1.0"; >
<topicRef xlink:href="#text" xmlns:xlink="http://www.w3.org/1999/xlink";>${request.getParameter("ref")}</topicRef>
</page>
The output, when accessed as URL_PATH/simple-jx?ref=Test is this:
<?xml version="1.0" encoding="ISO-8859-1"?>
<page xmlns:xsp="http://apache.org/xsp"; xmlns:db="http://apache.org/cocoon/xmldb/1.0";>
<topicRef xlink:href="#text" xmlns:xlink="http://www.w3.org/1999/xlink";>Test</topicRef>
</page>
In other words, you don't need a Cray to verify that the outcome of these three pipelines is IDENTICAL!!! The strangest thing was observed when I compared the output of the log transformers (enclosed after this message - differences are highlighted by *). All the name spaces would disappear form <page> tag when processed by the XSP, however, everything will be set back to normal when serialized (look at the outputted XML). JX and FILE generators would keep the name spaces intact.
The natural question to ask is why is it important if the result is the same. Well, the motivation behind it is to use XUpdate with XMLDBTransformer to interact with an eXist database (I made a post about that problem a few days ago). If I try to use XSP (or XSLT) to prepare the query, it would produce a failure. Exactly the same query (I used the same pipeline, but placed serializer before the XMLDB transformer, then saved the content as an XML file and used this new file with file generator and XMLDB transformer) worked out just fine with the name spaces manually added to the XML. Also, in case I remove the name space prefix form the XSP ( or XSLT ) then the SAME query works just fine with XSP ( XSLT ).
So the question is - what happens to the name spaces? Why are they being removed temporarily and then restored again? Is it a bug or is it me who don't possess sufficient knowledge of XML/XSL and Cocoon?
Thank you.
Sincerely, Nick.
FOR XSP:
[setup] ---------------------------- [Fri Jul 16 11:07:47 EDT 2004] ----------------------------
[setDocumentLocator] systemid=file:/C:/Simple/simple-query.xsp,publicid=null
[startDocument]
[startPrefixMapping] prefix=xml,uri=http://www.w3.org/XML/1998/namespace
[startPrefixMapping] prefix=xsp,uri=http://apache.org/xsp
[startPrefixMapping] prefix=db,uri=http://apache.org/cocoon/xmldb/1.0
[startElement] uri=,local=page,raw=page
[characters]
[startPrefixMapping] prefix=xlink,uri=http://www.w3.org/1999/xlink
[startElement] uri=,local=topicRef,raw=topicRef
[ ] 1. uri=http://www.w3.org/1999/xlink,local=href,qname=xlink:href,type=CDATA,value=#text
[characters] Test
[endElement] uri=,local=topicRef,raw=topicRef
[endPrefixMapping] prefix=xlink
[characters]
[endElement] uri=,local=page,raw=page
[endPrefixMapping] prefix=xml
[endPrefixMapping] prefix=xsp
[endPrefixMapping] prefix=db
[endDocument]
FOR FILE:
[setup] ---------------------------- [Fri Jul 16 11:07:56 EDT 2004] ----------------------------
[setDocumentLocator] systemid=file:/C:/Simple/simple-query.xml,publicid=null
[startDocument]
[startPrefixMapping] prefix=xsp,uri=http://apache.org/xsp
[startPrefixMapping] prefix=db,uri=http://apache.org/cocoon/xmldb/1.0
[startElement] uri=,local=page,raw=page
*[ ] 1. uri=,local=,qname=xmlns:xsp,type=CDATA,value=http://apache.org/xsp*
*[ ] 2. uri=,local=,qname=xmlns:db,type=CDATA,value=http://apache.org/cocoon/xmldb/1.0*
[characters]
[startPrefixMapping] prefix=xlink,uri=http://www.w3.org/1999/xlink
[startElement] uri=,local=topicRef,raw=topicRef
[ ] 1. uri=http://www.w3.org/1999/xlink,local=href,qname=xlink:href,type=CDATA,value=#text
*[ ] 2. uri=,local=,qname=xmlns:xlink,type=CDATA,value=http://www.w3.org/1999/xlink*
[characters] Test
[endElement] uri=,local=topicRef,raw=topicRef
[endPrefixMapping] prefix=xlink
[characters]
[endElement] uri=,local=page,raw=page [endPrefixMapping] prefix=xsp [endPrefixMapping] prefix=db [endDocument]
FOR JX:
[setup] ---------------------------- [Fri Jul 16 11:08:02 EDT 2004] ----------------------------
[setDocumentLocator] systemid=file:/C:/eclipse/workspace/Tapor-Portal/Testing/Simple/simple-query.jx,publicid=null
[startDocument]
[startPrefixMapping] prefix=xsp,uri=http://apache.org/xsp
[startPrefixMapping] prefix=db,uri=http://apache.org/cocoon/xmldb/1.0
[startElement] uri=,local=page,raw=page
*[ ] 1. uri=,local=,qname=xmlns:xsp,type=CDATA,value=http://apache.org/xsp*
*[ ] 2. uri=,local=,qname=xmlns:db,type=CDATA,value=http://apache.org/cocoon/xmldb/1.0*
[characters]
[startPrefixMapping] prefix=xlink,uri=http://www.w3.org/1999/xlink
[startElement] uri=,local=topicRef,raw=topicRef
[ ] 1. uri=http://www.w3.org/1999/xlink,local=href,qname=xlink:href,type=CDATA,value=#text
*[ ] 2. uri=,local=,qname=xmlns:xlink,type=CDATA,value=http://www.w3.org/1999/xlink*
[characters] Test
[endElement] uri=,local=topicRef,raw=topicRef
[endPrefixMapping] prefix=xlink
[characters]
[endElement] uri=,local=page,raw=page [endPrefixMapping] prefix=xsp [endPrefixMapping] prefix=db [endDocument]
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