Liferay Portlet and JSF : Redirect during Render Phase - redirect

Question

I have a problem to implement a simple HTTP redirection.
I use Liferay 6.0.6, our portlets are build with JSF2.0 / PortletFaces.
I want to call a redirection when a view is loaded (and not when an action is triggered). Currently, my function is called by the PreRenderView listener.
<f:metadata>
<f:event listener="#{myControler.dispatch}" type="preRenderView" />
</f:metadata>
In this function, i can check the permissions, do other stuff, and in some cases I want to redirect the user to a new page (not another view).
I tried several methods, unsuccessfully.
Specifically, I thought that this method would work :
getFacesContext().getExternalContext().redirect(url);
getFacesContext().responseComplete()
// => Can only redirect during ACTION_PHASE
This error is logical, but is there a solution to force the redirection.
It could be realized in another function, called otherwise, I only need the Hibernate Session (set at the beginning of the Render Phase)
Have you ideas to resolve this problem?
Thanks!
ps : <redirect /> or ?faces-redirect don't work with the portlets.

Answer 1

You can't do this in the render phase by design. Reasons:
It's possible that portlets are rendered asynchronously, so the page might already be displayed when your portlet is being rendered
It's possible that parts of the page are already delivered to the client, so that the HTTP Headers are already sent - for this reason, by design you don't have access to them in the render phase
What would be the expected outcome if two portlets rendered on the same page would decide that they'd like to forwards to another page? Who would win?
A hacky workaround is to render some javascript redirect, but this is veeeery un-portal-like and can mess up other's expectations (plus, parts of the page might already be rendered, causing your users to fill a form only to be redirected by your javascript routine.
Please rethink the problem and come up with a different solution - it's really worth doing this in a portal environment.

Answer 2

I use this and it works for me:
public void preRenderView() throws IOException {
if (!checkUtente()) {
FacesContext fc = FacesContext.getCurrentInstance();
NavigationHandler navigationHandler = fc.getApplication().getNavigationHandler();
navigationHandler.handleNavigation(fc, null, "errore.xhtml?faces-redirect=true");
fc.renderResponse();
}
}

Answer 3

Use the below method it will work
public static void redirect(final String url) throws IOException {
final javax.portlet.PortletResponse portletResponse
= getPortletResponse();
if (portletResponse instanceof ActionResponse) {
final javax.portlet.ActionResponse actionResponse
= (javax.portlet.ActionResponse) portletResponse;
actionResponse.sendRedirect(url);
} else if (portletResponse instanceof ResourceResponse) {
final FacesContext ctx = FacesContext.getCurrentInstance();
if (ctx.getPartialViewContext().isPartialRequest()) {
final ResourceResponse portletResResp
= (ResourceResponse) portletResponse;
PartialResponseWriter pwriter;
final ResponseWriter writer = ctx.getResponseWriter();
if (writer instanceof PartialResponseWriter) {
pwriter = (PartialResponseWriter) writer;
} else {
pwriter = ctx.getPartialViewContext()
.getPartialResponseWriter();
}
portletResResp.setContentType(Constants.CONTENT_TYPE);
portletResResp.setCharacterEncoding(Constants.ENCODING_TYPE);
// addResponseHeader("Cache-Control", "no-cache");
pwriter.startDocument();
pwriter.redirect(url);
pwriter.endDocument();
ctx.responseComplete();
} else {
throw new UnsupportedEncodingException(
"Can only redirect during RESOURCE_PHASE "
+ "if a Partial-(JSF AJAX)-Request has "
+ "been triggered");
}
} else {
throw new UnsupportedEncodingException(
"Can not redirect during the current phase: "
+ portletResponse.getClass().getSimpleName());
}
}