How to set response header in filter

Question

Hi,
i want to set the response header in my security filter:
private void setHeader() {
          FacesContext ctx = FacesContext.getCurrentInstance();
          if (ctx != null){
               HttpServletResponse response = (HttpServletResponse)ctx.getExternalContext().getResponse();
               response.setHeader("Pragma", "No-Cache");
               response.setDateHeader("Expires",0);
               response.setHeader("Cache-Control", "no-cache");
     }But ctx is always null? What am i doing wrong?
Regards,
barnti

Answer 1

My understanding is you will not have Faces Context in a filter as you have not yet hit the faces lifecycle..
Try the below to get the context.
     * (non-Javadoc)
     * @see javax.servlet.Filter#init(javax.servlet.FilterConfig)
    public void init(FilterConfig config) throws ServletException {
        setFilterCfg(config);
        setServletCtx(filterCfg.getServletContext());
     * Since your typical FacesContext.getCurrentInstance() will probably be
     * null due to the fact we have not hit the faces lifecycle yet, we must dup
     * some of the faces servlet code here to create a new current instance.
     * @param req
     * @param res
     * @return FacesContext which is fresh and virtually empty.
    protected FacesContext getFacesContext(ServletRequest req,
            ServletResponse res) {
        FacesContext facesContext = FacesContext.getCurrentInstance();
        if (facesContext != null) {
            return facesContext;
        //     Use the FactoryFinder to grab the Lifecycle object
        FacesContextFactory contextFactory = (FacesContextFactory) FactoryFinder
                .getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);
        LifecycleFactory lifecycleFactory = (LifecycleFactory) FactoryFinder
                .getFactory(FactoryFinder.LIFECYCLE_FACTORY);
        Lifecycle lifecycle = lifecycleFactory
                .getLifecycle(LifecycleFactory.DEFAULT_LIFECYCLE);
        facesContext = contextFactory.getFacesContext(servletCtx, req, res,
                lifecycle);
        ProtectedFacesContext.setFacesContextAsCurrentInstance(facesContext);
        return facesContext;
    }