Hi,
On Fri, Jan 15, 2016 at 7:15 PM, Xavier Dury <kalgon_at_hotmail.com> wrote:
> <url-mapping id="document">
> <pattern value="/document/#{id}" />
> <view-id value="/document.xhtml" />
> </url-mapping>
>
> I don't think replacing #{id} with #{requestScope.id} in the prettyfaces
> configuration will work.
>
Okay, so it's PrettyFaces that essentially does the write to #{id} which
will end up in request scope? (I don't know PrettyFaces that well).
Depending on what PrettyFaces exactly does you could try it though. If it's
a general value expression where whatever comes after /document/ is written
to it may actually have a chance of working.
> I don't know if there are other places in the code where
> UIViewRoot.getViewMap() is being called without considering that the
> current view may be transient.
>
I think the view being transient or not does not even matter that much.
After all, you can also have a view that simply doesn't use a form (so no
state) or have state written to the client.
What (IMHO) matters most is that code, and specifically frameworks, should
always be wary of accidentally creating sessions when not strictly
necessary.
>
> ------------------------------
> Date: Fri, 15 Jan 2016 17:18:57 +0100
> Subject: Re: JAVASERVERFACES-3939
> From: arjan.tijms_at_gmail.com
> To: dev_at_javaserverfaces.java.net
>
> Hi,
>
> On Fri, Jan 15, 2016 at 4:31 PM, Xavier Dury <kalgon_at_hotmail.com> wrote:
>
>
> String attribute = (String) property;
> FacesContext facesContext = (FacesContext)
> context.getContext(FacesContext.class);
> ExternalContext ec = facesContext.getExternalContext();
> if ((ec.getRequestMap().get(attribute)) != null) {
> ec.getRequestMap().put(attribute, val);
> } else if ((facesContext.getViewRoot()) != null &&
> (facesContext.getViewRoot().getViewMap().get(attribute)) != null) {
> facesContext.getViewRoot().getViewMap().put(attribute,
> val);
> } else if ((ec.getSessionMap().get(attribute)) != null) {
> ec.getSessionMap().put(attribute, val);
> } else if ((ec.getApplicationMap().get(attribute)) != null) {
> ec.getApplicationMap().put(attribute, val);
> } else {
> // if the property doesn't exist in any of the scopes, put
> it in
> // request scope.
> ec.getRequestMap().put(attribute, val);
> }
>
>
> This code seems indeed problematic. The view map is created only to check
> it, which not only causes an annoying warning, it also causes the creation
> of a session.
>
> The same thing holds for the session map check.
> ec.getSessionMap().get(attribute) will create a session, even when this
> would not be needed.
>
> For some types of applications, the needless creation of sessions is a
> serious problem. So regardless of the message being annoying or not, or
> clear or not, this session creation seems problematic to me.
>
> The question is; how strict is the spec about mandating this?
>
> Regardless, wouldn't changing the value expression mentioned in the issue
> to one that explicitly contains the scope work around a particular instance
> of this problem?
>
> E.g.
>
> ValueExpression ve = ef.createValueExpression(context.getELContext(),
> "#{requestScope.id}", Object.class);
>
> instead of
>
> ValueExpression ve = ef.createValueExpression(context.getELContext(),
> "#{id}", Object.class);
>
> ?
>
>
>
>
>
>
>