Question

I have JSF pages which have links to other JSF pages . When I click on the link and if the session has already expired , control goes to login page. And I will login with username password and again come to same page where I have clicked on link. Now I will click on the link, a blank page is getting displayed, and if i do page refresh by F5, the expected page loads.

And also I have checked the console on my Jboss server, the View Expired exception is not appearing.

SO I am bit confused which way I handle this to avoid blank page getting displayed.

Please help.

Answer 1

This can happen if you’re performing link navigation by ajax and the page returned after login was been served from the browser cache (and thus contains a form with an outdated view state identifier). You need to tell the browser to not cache restricted pages. You can achieve this with the following filter:

@WebFilter(servletNames={"Faces Servlet"})
public class NoCacheFilter implements Filter {

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpServletResponse res = (HttpServletResponse) response;

        if (!req.getRequestURI().startsWith(req.getContextPath() + ResourceHandler.RESOURCE_IDENTIFIER)) { // Skip JSF resources (CSS/JS/Images/etc)
            res.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.
            res.setHeader("Pragma", "no-cache"); // HTTP 1.0.
            res.setDateHeader("Expires", 0); // Proxies.
        }

        chain.doFilter(request, response);
    }

    // ...
}

Note that this problem thus also suggests that you’re using (ajax) command links for page-to-page navigation. This is a bad practice. Those links are not SEO friendly nor bookmarkable. Command links should be used for form submits only. Use normal links for page-to-page navigation. See also When should I use h:outputLink instead of h:commandLink?