Apply Filter to static content

Question

Hi,
I am writing a filter very similar to the one outlined in http://developer.java.sun.com/developer/JDCTechTips/2001/tt0626.html#tip2.
I would like this filter to be applied to all static content on the web server.
I have found a problem that the filter only gets applied to content stored under the context root of the web module that it is defined in.
Does anyone know of a work-around to allow a filter to be applied to content outside of its web-module?
Alternatively does anyone know of a way to store the content which appears at the root of a web module in a location other than its web-module? This is currently unacceptable as the physical path changes every time the module is deployed and graphic designers will expect to be able to upload new content without packaging it in a web-module!
I have considered adding the filter to the /config/web.xml file however I am reliably informed that this will not be applied to any web-modules and will not be able to share session or context state with other servlets and filters in its own web-modeule.
I am using SunOne Application Server 7.
Thanks in advance for any help.

Answer 1

I don't think filters are really the way to go about this, rather, create a servlet that handles requests something along these lines:
void service(HTTPServletRequest request, HTTPServletResponse response) {
  // get document root, base directory for all the xml files
  String docRoot = request.getServletConfig().getParameter("docroot");
  // get the document name
  String path = request.getPathInfo();
  // do some checking on path to make sure it doesn't contain
  // '..' or anything like that, throw an exception if it does.
  // create a java.io.File object representing the file:
  File file = new File(docRoot, path);
  if (/*browser is IE6*/) {
    // open the file (using FileInputStream) and copy it to
    // request.getOutputStream()
  else {
    // pass the file through an xslt transformation that outputs
    // to request.getOutputStream()
}If this servlet is bound to a context called "context1", and the servlet is bound to "xml", requests for eg. /context1/xml/dira/dirb/doc1.xml will result in request.getPathInfo() returning "/dira/dirb/doc1.xml", given that the servlet-mapping element in web.xml is specified correctly (use a wild card: /xml/*).
And be warned, I just typed this in without trying to compile it, so it probably contains bugs!