You are viewing a plain text version of this content. The canonical link for it is here.

Posted to users@cxf.apache.org by Gary Gregory <GG...@seagullsoftware.com> on 2009/12/18 10:13:29 UTC

Inflexible fault interceptor chain?

Hi All:

I need to apply an XSL transformation to messages coming out of CXF (our users configure what the XSL looks like.) For a normal (successful) message, I have an interceptor (during Phase.PRE_MARSHAL) that uses the DOM aspect of a message. That works great. BTW, I get to the DOM like this:

Node node = (Node) message.getContent(List.class).get(0);

That seems brittle, is there a safer way to get to an aspect of the message I can feed to javax.xml.transform?

The real issue comes with fault messages because the fault chain uses an XMLStreamWriter<http://java.sun.com/javase/6/docs/api/javax/xml/stream/XMLStreamWriter.html>. The fault chain looks like this:

Chain org.apache.cxf.phase.PhaseInterceptorChain@3015b303. Current flow:
  setup [ServerPolicyOutFaultInterceptor]
  prepare-send [MessageSenderInterceptor, Soap11FaultOutInterceptor]
  pre-stream [LoggingOutInterceptor, XmlDeclOutInterceptor*, StaxOutInterceptor]
  pre-protocol [WebFaultOutInterceptor, SOAPHandlerFaultOutInterceptor]
  write [SoapOutInterceptor]
  pre-marshal [LogicalHandlerFaultOutInterceptor]
  marshal [Soap11FaultOutInterceptorInternal]
  pre-stream-ending [StaxOutEndingInterceptor, TransformOutFaultInterceptor*]
  prepare-send-ending [MessageSenderEndingInterceptor]

FYI, the interceptors marked with * are our own:

*         XmlDeclOutInterceptor forces an XML declaration to be written.

*         TransformOutFaultInterceptor is where I thought I could transform the fault XML message.

The XMLStreamWriter<http://java.sun.com/javase/6/docs/api/javax/xml/stream/XMLStreamWriter.html> looks like this:

[StreamWriter: class com.ctc.wstx.sw.SimpleNsStreamWriter, underlying outputter: com.ctc.wstx.sw.ISOLatin1XmlWriter@1125cf44<ma...@1125cf44>

The com.ctc.wstx.sw.ISOLatin1XmlWriter wraps a org.apache.cxf.io.CachedOutputStream, which in turns wraps:

*         currentStream - LoadingByteArrayOutputStream

*         flowThroughStream - AbstractHTTPDestination$WrappedOutputStream

All of this to say that when the chain's interceptors are working with the message's XMLStreamWriter<http://java.sun.com/javase/6/docs/api/javax/xml/stream/XMLStreamWriter.html>, the bytes are cached and written to the wire. It is not possible to catch the fault XML message and change it.

The only thing I've come up with but not implemented yet would be to insert an interceptor before the XML declaration is written and put the XMLStreamWriter<http://java.sun.com/javase/6/docs/api/javax/xml/stream/XMLStreamWriter.html> into a temp spot in the message content map, then put a new XMLStreamWriter<http://java.sun.com/javase/6/docs/api/javax/xml/stream/XMLStreamWriter.html> on a byte array in its place. A pre-stream-ending interceptor can take those bytes, apply XSL to them and then write them to the original XMLStreamWriter<http://java.sun.com/javase/6/docs/api/javax/xml/stream/XMLStreamWriter.html>, before putting the original XMLStreamWriter<http://java.sun.com/javase/6/docs/api/javax/xml/stream/XMLStreamWriter.html> back in it original slot in the message content map.

That seems like big old hack.

Any ideas on a cleaner solution?

Thank you,
Gary Gregory
Seagull Software
ggregory@seagullsoftware.com
www.seagullsoftware.com