On Thu, 2014-03-13 at 23:16 -0400, Tim Watts wrote:
> On Thu, 2014-03-13 at 19:11 -0700, Brendan Miller wrote:
> > 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.
Actually, let me correct myself: that may not be strictly true. I don't
think there's anything in the spec that says the response code will be
set when service() returns UNLESS the request results in an error.
-- Tim.
> 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
> > >
> > >
>
>
>
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
> For additional commands, e-mail: users-h...@tomcat.apache.org
>
---------------------------------------------------------------------
To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org
For additional commands, e-mail: users-h...@tomcat.apache.org
