code: public static String getThrowableResourceUri(ServletRequest req) {
  
          CmsFlexController controller = (CmsFlexController)req.getAttribute(ATTRIBUTE_NAME);
          if (controller != null) {
              return controller.getThrowableResourceUri();
          } else {
              return null;
          }
      }
docs: Provides access to URI of a VFS resource that caused an exception that might have occurred in a complex include scenario.<p>
  
  @param req the current request
  
  @return to URI of a VFS resource that caused an exception, or <code>null</code>
  
  @see #getThrowableResourceUri()