Re: Passing an Object from the servlet through to the provider?

[Glen Daniels]

Hi James!

James M Snell wrote:
RequestContext.setAttribute(Scope scope, String name, Object value) ... 
where Scope == Scope.REQUEST or Scope.SESSION

Does that work for what you need?

Nope, because that implies you have access to the RequestContext, which 
I don't.  Even if I subclass AbderaServlet, there's no hook in service() 
that lets me get at the ServletRequestContext in between creation and 
passing it to the Provider/TargetResolver.

To be clear, here's my situation:

class Servlet1 {
  init() {
    Object thing = createObject(); // Here's my thing
    servletContext.setAttribute("thing", thing);  // Store it somewhere
  }
}

class MyServlet extends AbderaServlet {
  service(request, response) {
    // I can't get at the ServletContext from within Abdera, so...
    Object thing = servletContext.getAttribute("thing");
    // ...put it somewhere I *can* get to
    request.setAttribute("thing", thing);
    super.service(request, response);
  }
}

If AbderaServlet made the ServletContext available in the same way it 
makes the HttpServletRequest available, I wouldn't need the subclassed 
servlet or the per-request overhead.

--Glen

Glen Daniels wrote:
Hey Abderites:

So here's my situation.  I've got an Abdera server (i.e. AbderaServlet 
in Tomcat) running that needs to share some information with another 
servlet.  In particular, the non-AbderaServlet (let's call it 
Servlet1) needs to create an Object and then in an ideal world pass 
that through to the AbderaServlet in such a way that the Provider 
instance that gets created has access to it.  Make sense?

The best solution for me would be to put something into the 
ServletContext, and then somehow get access to that later - but I 
can't seem to do that currently.

Since the initialization step doesn't really need to be done until the 
first actual request, and I've already got a solid connection between 
my Provider and my TargetResolver, I figured one way would be 
something like (pseudocode):

TargetResolver.resolve(Request request) {
  ServletRequestContext context = (ServletRequestContext)request;
  if (thing == null) {
    thing = context.getServletContext().getAttribute("thing");
  }
}

A patch that would just carry the ServletContext in addition to the 
HttpServletRequest in each ServletRequestContext would be very easy to 
do in Abdera, and would get me what I need.  Am happy to contribute same.

Is there a better way to do this?  I noticed the ManagedProvider stuff 
but it looks like you can only pass Strings in there, and only in very 
specific ways.  Perhaps some kind of more general initialization 
context that I'm missing?  The above patch would solve my problem 
later but not in v0.4.0.

The solution I've come up with for now is to subclass the 
AbderaServlet, and add the ServletContext to every HttpRequest as an 
attribute - that lets me do basically the same trick, but it seems... 
less than optimal.

Thoughts/comments?

Thanks,
--Glen