Question

My problem is similar to the one here but doesn’t involve PrimeFaces in any way. Also, I couldn’t find a real solution there.

I’m basically trying to get the phaselistener to redirect to login page in case there is no JSF session (When, for example, session has timed out)

I’m trying to redirect from within a JSF 2 Phaselistener. To sum up, what I’m doing is this:

public void beforePhase(PhaseEvent event) {
    PhaseId id = event.getPhaseId();
    if(id.equals(PhaseId.RESTORE_VIEW)){
        FacesContext context = event.getFacesContext();
        Map<String, Object> sessionMap = context.getExternalContext().getSessionMap();
        if(sessionMap==null || sessionMap.isEmpty()){
            // No Session, Redirect to login
            try {
                context.getExternalContext().redirect("/login");
            } catch (Exception e) {
                ...
            }
        }
    }
}

When the redirect code runs I get this exception:

java.lang.NullPointerException
        at org.apache.myfaces.context.servlet.PartialViewContextImpl.getPartialResponseWriter(PartialViewContextImpl.java:301)
        at org.apache.myfaces.context.servlet.ServletExternalContextImpl.redirect(ServletExternalContextImpl.java:452)
        at com.AuthenticationPhaseListener.userIsNotLogedIn

What could be causing this? Am I doing this wrong?

Thanks!

Answer 1

This seem to be happening during an ajax request. I’m not sure about the exact cause, the stacktrace at least indicates a possible bug in MyFaces implementation.

At least, the overall design approach is poor. This kind of HTTP request/response modifications should preferably not take place in a PhaseListener. There it is not intended for. You want to do this kind of job in a normal servlet Filter instead.