I am building a CRUD web application using JSF. I have a problem with loading a page after the user session has timed out. That is i lose the parameters I need to construct the view (even though the parameters are still visible in the url like so: 'someurl/view.xhtml?pid=5'.
In the .xhtml file the parameter pid is used to load some content from an underlying database when constructing the view. When the user has been inactive for a while their session times out, and if they try to reload the page in the browser they are forwarded to the login page (the 'someurl/view.xhtml?pid=5' still intact) and on succesful login go back to the view.xhtml page where I wan't the view to be constructed as if their session had never timedout.
However this does not happen because the 'pid' parameter is no longer set in the view. But since the 'pid' parameter is still visible in the url I feel like I should be able to get it into the view and load the protein with this id from the database.
These are the things I've tried:
#{protein.setProteinById(param.pid)}
and
#{protein.setProteinById(param['pid'])}
and
#{protein.setProteinById(request.getParameter('pid'))}
and
<c:set value="${request.getParameter('pid')}" var="pid" />
#{protein.setProteinById(pid)}
Is this possible to do? Then how?
I'm no expert, but wouldn't you set it in the managed bean?
As far as I know there are two methods for doing this.
One method is using in your facelet to push a view parameter back into a bean (I have a scenario where this doesn't work because of other things, so have no experience with it)
What can <f:metadata>, <f:viewParam> and <f:viewAction> be used for?
I have a prerender method, which is always called before a render
<f:metadata>
<f:event type="preRenderView" listener="#{MyController.prerenderMethod}" />
</f:metadata>
And inside the method, I look at the parameters:
public void prerender(ComponentSystemEvent event) {
value = FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap().get("key");
}
Related
Lets say I have a #ViewScoped Bean behind my current page A. Now the user navigates to page B via a normal get request, lets say to www.google.com.
When the user clicks the back button of the browser, I would like to restore the #ViewScope of the previous page, so that it appears exactly as it was left. Is that possible to achieve somehow?
I dont want to make my page A #SessionScoped so that the backing beans do not disturb each others state when opened in two browser tabs.
Since version 2.6 OmniFaces has this feature, is called #ViewScoped(saveInViewState = true) But with some caution!
It's very important that you understand that this setting has potentially a major impact in the size of the JSF view state, certainly when the view scoped bean instance holds "too much" data, such as a collection of entities for a data table, and that such beans will in fact never expire as they are stored entirely in the javax.faces.ViewState hidden input field in the HTML page. Moreover, the #PreDestroy annotated method on such bean will explicitly never be invoked, even not on an unload as it's quite possible to save or cache the page source and re-execute it at a (much) later moment.
A more programmatical solution is the #ConversationScoped. With the convertsation id as parameter can you restore the view.
conversationscope example
Yes it is possible, pass parameter like this using f:param this will pass your parameter to the next screen.
<h:commandLink action="screenName" value="#{search.participantName}">
<f:param value="#{searchcus.participantId}" name="PARTICIPANT_ID"/>
<f:param name="PARENT_SCREEN_CODE" value="SEARCH_PARTICIPANT"/>
</h:commandLink>
After that in init() method get value as a parameter to fetch the result.
I use a backing bean where I can save a form and navigate to this page.
public String saveHere() {
return Faces.getViewId() + "?faces-redirect=true&includeViewParams=true";
}
How do I navigate to the previous page with OmniFaces?
My save action should result in the page where I have the "edit" button.
Typically a list-view (with edit-button next to very item)
or another page with (with edit-button to this item)
Thanks!
You need the page id you're navigating from somewhere. At first look, keeping it in Session seems to be a good idea, however, this could remain in coflict if you're navigating in multi-tab (sharing same Http Session through different browser tabs).
Having said that, the most proper solution for your case is to pass a view param to your edition view telling where you're coming from. That should be as easy as this:
<h:button outcome="edit" value="Edit registry">
<f:param name="pageFrom" value="#{view.viewId}" />
</h:button>
After that, in your edition view bind this param to your bean:
<f:metadata>
<f:viewParam name="pageFrom" value="#{editBean.pageFrom}" />
</f:metadata>
And just redirect to that view in your EditBean.java after saving, supposing it is #ViewScoped:
public String saveHere() {
//save here
return pageFrom + "?faces-redirect=true&includeViewParams=true";
}
That's the most straight forward way to achieve what you ask for. However, you must take into account the page where you're coming from remains to be a view parameter, so the end user could type what he wants there. With this behaviour, he could achieve being redirected to some other page rather than the one expected. If you want to avoid that, go with the flash scope instead of view parameters.
See also:
Get current page programmatically
How can I control what customscope is created during request. Right now I have solution that when I click the commandLink:
<h:commandLink action="orders">
<f:actionListener type="com.mk.web.jsf.scope.ResetScopeListener" />
<span data-shortcut="F6" class="start_link">Orders</span>
</h:commandLink>
The custom scope is destroyed and a new one is created. But the problem is that the custom scope only resets if I enter the customers action using this commandLink from above.
When I enter to customers action by directly entering the url in browser the custom scope is not reset. How can I make that is customers action is loading even by commandLink or by url then always this custom scope should be reset. Can somebody give me some advice how to achieve this?
Thanks...
Typically you use a custom scope when you want your beans to live longer than the original request but shorter than the session. Based on your scenario though, it seems to me that your custom scope is behaving slightly like a request scope. Anyway, maybe I'm not understanding your scenario fully but one thing that comes to mind is that you can use system events in case a user decides to go to the next page when they type the address directly. So suppose the user tries to go to nextPage.xhtml, it could be defined like this
<f:event type="preRenderView" listener="#{bean.performPossibleCustomScopeCleanUp}" />
<h:head>
</head>
The (pseudo) method above will fire before the view root (aka nextPage.xhtml) is rendered. Inside the method you can check to see if your custom scope is still "alive" and you will handle it as needed. Keep in mind though that this event will be fired every time the page is requested. For instance, if you click the h:commandLink performPossibleCustomScopeCleanUp will still be invoked. There are ways around that
What can <f:metadata>, <f:viewParam> and <f:viewAction> be used for?
Just scroll down to the section Performing business action on GET parameters of the answer
An even better approach would be to implement a custom NavigationHandler through JSF's ConfigurableNavigationHandler API so you can keep track of the URL and perform actions as needed.
I didn't dig too dig so you might actually find a better code sample. Hope this helps.
I want to know how to get the name of the page that requests another JSF page to further call specific methods in the bean according to the source page, i don't want to use <f:event type="preRenderView"
listener="#{beanName.preRender}" /> because the specified page has components that's rendered according to the source page
AS far as I know this has to be handcoded and the best way to do it is probably in a #WebFilter. and request.getRequestURI();
Then simply save the pages in a suitible fashion for example ArrayDeque.
The ArrayDeque could for example be saved in a #SessionScoped bean.
Is it possible to get a reference to the to-be-executed managedbean in the before-invokeApplication-phaselistener ?
Before the invoke application phase, it should be clear which managedBean that is going to execute the method.
For the sake of the example, assume there's 1 main manage bean to handle 1 jsf page.
So what i need is basically :
The user access the program from the menu
Because it's accessed from the menu, the main manage bean's init() method gets called to initialize stuffs like preparing data, doing authorization checks
Subsequent submits dont need to call the init() method anymore until it's reaccessed from the menu
To implement the point #2, im thinking of intercepting one of the phases
I've checked the API docs about getting the managed bean in the phases implementation, but i couldnt seem to find any.
After typing this question, i realize i could do this in #PostConstruct or the managed bean's constructor, but that would do only at the first time the bean is constructed, and my need is to call the method everytime the jsf is being accessed from the menu.
Any suggestions ?
Regards,
Albert Kam
You can access your managed beans via the ELContext/ELResolver. This is explained nicely in the MyFaces wiki (also works in vanilla JSF).
For example:
ELContext elContext = FacesContext.getCurrentInstance().getELContext();
NeededBean neededBean = (NeededBean) FacesContext.getCurrentInstance().getApplication()
.getELResolver().getValue(elContext, null, "neededBean");
See the MyFaces wiki entry for further explanation, and implementations for other JSF versions.
Your idea of using #PostConstruct is a good one. Consider changing your scope to something liked #ViewScoped, so the logic is executed everytime you navigate to that view.
Also, have a look at the PreRenderViewEvent (for JSF 2). This code is embedded in your facelet page:
<f:metadata>
<f:viewParam name="foo" value="#{bean.foo}"/>
<f:event type="preRenderView" listener="#{bean.doSomething}"/>
</f:metadata>
The f:event listener is executed before every page view.