Hello, all,
I'm trying to find a way to modify the content of a servlet
after the servlet has completed all of its processing but before
it actually gets sent to the browser (obviously).
Here's the context. Our web site stores all its content in XML.
All servlets, jsps, and static files return this XML and what
I'd like to do is turn it all into HTML on the fly without each
servlet, etc., having to worry about doing the transformation
itself. My naive first idea was to set the content-type to
text/cml (CML is the name of the markup language) and have a
CmlToHtmlInterceptor (extends BaseInterceptor) with a afterBody
method that would check the content-type and if it's text/cml,
retrieve the contents (maybe from a ByteBuffer), run it through
an XSL engine, turning it into HTML and sending that back after
changing the appropriate headers (content-type, content-length,
etc.).
Here are my problems: 1) I don't understand the order in which
the interceptor methods are called. Should this be done in
afterBody? postService? Is the calling sequence documented
anywhere? 2) I don't understand the relationship between
ByteBuffers and ServletOutputStreams. Or am I completely barking
up the wrong tree? Maybe what I mean to ask is how do I get the
contents of a servlet in a way that's suitable for modification?
3) This is incidental, but Request.getContentLength() always
gives me a -1 when called in afterBody and postService.
Request.getOutputBuffer().count (correctly) gives me 8192 (for
the small pages I've done). How/where do I get an accurate
content-length?
One level up, does this seem like a reasonable way to do the
transformation of aggregate XML docs? I didn't want to make a
TransformationServlet and have everything forward requests off
to it for a number of reasons -- orthogonality being a prime
one. On the other hand, my understanding of the Tomcat 3.1 code
base is spotty at best. I may have no idea what I'm doing. Any
feedback would be most appreciated!
Thanks,
Alex
__________________________________________________
Do You Yahoo!?
Yahoo! Shopping - Thousands of Stores. Millions of Products.
http://shopping.yahoo.com/
