On Thu, 2014-03-13 at 19:11 -0700, Brendan Miller wrote:
> I'm confused by what you mean by that. Are you saying I need to somehow
> rewrite the class of the FilterChain object passed to my filter?
>
I think you're somewhat new to the list. Mr. Gainty is notorious here
and seems to pride himself on concocting the most off-the-wall red
herrings imaginable. I'll admit some of them are truly breathtaking. I
guess it's some sort of quest to build a global reputation as the
world's most incompetent developer. I dunno.
> To be clear, I'm trying to modify the response that comes back from the
> service. I have a header that I may or may not need to set based on the
> response code. I believe the service sets the response code?
That's true. Unfortunately, by the time your filter gets control again,
the response will very likely be committed thus shutting out any
possibility of setting any headers.
Doing this in a Filter, while intuitively sensible, will always be a
highly fragile solution. You would have to set a buffer large enough to
accommodate the largest conceivable response size. Once a response is
committed you can't set the response code or headers -- they're already
on their way to the client. There's no getting around this.
I think the best approach is to conditionally set the header before any
response is generated. If your application has an MVC structure you
could do this just before the Controller invokes the View. You should
know the response code by then.
HTH
-- Tim
>
>
> On Thu, Mar 13, 2014 at 6:20 PM, Martin Gainty <mgai...@hotmail.com> wrote:
>
> > you'll need to pass your modified response to service method of servlet
> > which is *in* the filterChain
> >
> >
> > ApplicationFilterChain::internalDoFilter(ServletRequest request,
> > ServletResponse response)
> > throws IOException, ServletException
> >
> > {
> > ............
> > servlet.service(request, response);
> >
> > ...........
> >
> > }
> >
> > Martin
> >
> >
> >
> >
> >
> >
> > > Date: Thu, 13 Mar 2014 17:51:59 -0700
> > > Subject: filter question
> > > From: catph...@catphive.net
> > > To: users@tomcat.apache.org
> > >
> > > I have a filter with doFilter method like this:
> > >
> > > public void doFilter(ServletRequest request,
> > > ServletResponse response,
> > > FilterChain chain)
> > > throws IOException, ServletException {
> > > HttpServletRequest req = (HttpServletRequest) request;
> > > HttpServletResponse resp = (HttpServletResponse) response;
> > >
> > > resp.setHeader("Cache-Control",
> > > "must-revalidate, max-age=0, post-check=0,
> > > pre-check=0");
> > >
> > > chain.doFilter(request, response);
> > > }
> > >
> > > This sets the header. However, if I set the header *after*
> > chain.doFilter,
> > > the header is not set. Why is this?
> > >
> > > public void doFilter(ServletRequest request,
> > > ServletResponse response,
> > > FilterChain chain)
> > > throws IOException, ServletException {
> > > HttpServletRequest req = (HttpServletRequest) request;
> > > HttpServletResponse resp = (HttpServletResponse) response;
> > >
> > > chain.doFilter(request, response);
> > >
> > > resp.setHeader("Cache-Control",
> > > "must-revalidate, max-age=0, post-check=0,
> > > pre-check=0");
> > > }
> > >
> > > Programmatically I can see the header is null.
> > >
> > > Has the content already been sent to the web browser after
> > chain.doFilter?
> > > If so, is there a way to delay sending data to the browser? I need to
> > > inspect the status code in the response before setting my header (to
> > > prevent 404's from being cached).
> > >
> > > Thanks,
> > > Brendan Miller
> >
> >
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