Multiple sessions

arusha · October 11, 2012, 5:32am

Hi Experts,

Am facing an issue, how can I handle multiple sessions? Please suggest

I have developed a Login page and Main page, Now when I open a browser and login through login window and now I open another browser and now my I should be in the login page but, currently am being taken to main page. Can someone help me on this ?

Thanks,
Arun

Kim2 · October 11, 2012, 6:35am

Not an expert, but we use following template for our Application:

public class MyApplication extends Application implements HttpServletRequestListener
{
// use InheritableThreadLocal to ensure that child threads can also get the current application
private static ThreadLocal currentApplication = new InheritableThreadLocal();
public static MyApplication getInstance()
{
    return currentApplication.get();
}

@Override
public void init()
{
    currentApplication.set(this);
}

@Override
public Window getWindow(String name)
{
    Window window = super.getWindow(name);

    // If not, we must create a new window for this new browser window/tab
    if (window == null) {
        LOG.trace("[{}]
no window yet, creating one", name);
     window = new MyApplicationWindow();

     // Use the random name given by the framework to identify this
     // window in future
     window.setName(name);
     addWindow(window);

     // Move to the url to remember the name in the future
     window.open(new ExternalResource(window.getURL()));
 }
 return window;
}

@Override
public void onRequestStart(HttpServletRequest request, HttpServletResponse response)
{
currentApplication.set(this);
clientAddress = request.getRemoteAddr();
}

@Override
public void onRequestEnd(HttpServletRequest request, HttpServletResponse response)
{
currentApplication.set(null);
clientAddress = null;
}
}

And the MyApplicationWindow class:

public class MyApplicationWindow extends Window
{
@Override
public void attach()
{
super.attach();
    showScreen();
}

private void showScreen()
{

    if (getApplication().getUser() != null) {
        showMainScreen();
    } else {
         showLoginScreen();
        }
    }
}
}

There are some essential parts to this (if I remember correctly, we haven’t touch this part of the code for over a year I think):-

Multiple application instances are managed thourhg a combination of thread-local and the HttpRequestListener, to switch to the correct instance based on the request (if there is connection pooling going on for example).
getWindow() creates a new Application Window if there isn’t one yet
the application window can get a reference to the corresponding Application instance via the getApplication method.
the application window can then retrieve all state for that application (like is there already a user logged in, etc.) to show the correct screen

I changed the code to pseudo code, so it might not be entirely syntactically correct, but it hopefully gives you some pointers on where to look for more information.
The multiple application stuff might not be required for your use case, but it makes the picture more complete, since you will end up with multiple applications in case you have multiple sessions, and you will probably have application code that needs to get a handle to the associated Application instance.

Bobby · October 11, 2012, 6:13pm

If you’re using 2 browsers, then you have 2 sessions. There’s no way for more than one browser to share the same session (without some serious hacking around!). Are you sure you mean a separate browser and not a separate tab in the same browser?

If you’re seeing the same info in more than one session, then there’s some problem in your app that you’re not storing data properly within the Vaadin application object. Are you using any static variables? That would lead to the kind of behavior you’re seeing.

Cheers,
Bobby