webpage expired when back button pressed on JSF(Richfaces) submit

Question

My title maybe confusing so please read on. I'm using the following technologies if you may. Spring, Hibernate, JSF (RichFaces), MySQL, Internet Explorer.

I have a List of items which is displayed in a RichFaces datatable like so:

item a
item b
item c
item d
item e

On the same page I have the following buttons: search, edit, add, delete and new.

When an user enters a search string, e.g. "item c", and press search button, then it displays a list of matching items, e.g:

item c

When the user presses the new button, the request will be redirected to another page using:

FacesContext facesContext = FacesContext.getCurrentInstance();
facesContext.getExternalContext().redirect(page + ".jsf" );

When the browser back button of IE is been pressed on that page, the page displays "web page expired". What is this and how can I avoid this?

Answer 1

web page expired

You will get this error when you're trying to obtain a non-cached POST request from the browser history. This behaviour is fully expected. To fix this "problem", you need to either turn the cache on or to replace POST by GET.

Enabling the browser cache is actually easy: just remove the Cache-Control: no-cache and related headers from the HTTP response of the POST request in question. The enduser will then only get a warning dialog that the POST data will be resent to the server, which in case of fully non-idempotent requests like placing an order or deleting an item is really not desirable. Replacing POST by GET is then a better solution. Getting searchresults (like as Google does) should really be done by GET.

Replacing POST by GET isn't easy in JSF prior to version 2.0. Best what you can do is to fire a redirect after the POST and pass the data of interest as request parameter which you retain from #{param} as managed property (more recommended) or store the data of interest in session scope (not recommended). A completely different alternative is to replace the JSF <h:form> by a simple HTML <form action="searchresults.jsf"> and do the search job in a @PostConstruct method in the backing bean associated with searchresults.jsf, after the submitted query has been gathered as managed property or from request parameter map.