Re: Session in Applet??

[Christian Kurze]

Thanks! That sound quite logical. I'll try it.

 

A happy new year to all!

 

Christian

-----Original Message-----
From: A mailing list about Java Server Pages specification and reference [mailto:[EMAIL PROTECTED]]On Behalf Of Zvika Markfeld
Sent: Monday, December 31, 2001 1:37 AM
To: [EMAIL PROTECTED]
Subject: Re: Session in Applet??

I now see your problem.
What you need to do in that case, I reckon, is send keepalives from the applet to the very same sevlet which generated the page, using the URL given upon calling  applet's getDocumentBase() method, and write you servlet code so that UR Rewriting is enabled (using response.encodeURL()).
here's how it should go:
1. Client presses a link which leads him/her to the page containing the applet.
2. The applet is loaded and started.
3. Using some sort of keep-alive thread, the applet performs something like:

URL whereICameFrom = this.getDocumentBase();

// this will return a url similar to

// http://myserver:80/chat?sessionid=243523657892638947

whereICameFrom.openConnection().getContent();

and do this periodically. This will cause some extra overhead in network traffic, but it will allow, to my opinion, maintaining the session. the servlet container will resume the session based on the session id supplied in the url.

zm.

-----Original Message-----
From: A mailing list about Java Server Pages specification and reference [mailto:[EMAIL PROTECTED]]On Behalf Of Christian Kurze
Sent: Monday, December 31, 2001 2:02 AM
To: [EMAIL PROTECTED]
Subject: Re: Session in Applet??


Yes I know. I implemented a chat-webapp, based on JSPs and Servlets. It
worked with some JavaScript code. I used some examples from JavaWorld
(http://www.javaworld.com/javaworld/jw-03-2000/jw-03-pushlet_p.html). But
that doesn't work with some browsers, e.g. Opera. I used the session to
'save' a bean, the chatuser. In this bean all the properties are set.
The problem is that the chat is part of a large community-framework and the
session timeout is set to 15 minutes. So if someone chats, this session
MUSTN'T get lost. In my JavaScript solution it worked very fine.
But now my chef wants that there should be a chatapplet. And I don't really
know how to maintain the session while the user chats. After 15 minutes he
or she will be logged out. Can I access to Cookies in an applet? But there's
the next problem, if someone deactivates cookies it either won't work. But
the whole community should be as browser-independent as possible.

Either I'm already sitting on a solution or I should open the window to get
some fresh air ;-)

Christian

> -----Original Message-----
> From: A mailing list about Java Server Pages specification and reference
> [mailto:[EMAIL PROTECTED]]On Behalf Of Zvika Markfeld
> Sent: Monday, December 31, 2001 12:16 AM
> To: [EMAIL PROTECTED]
> Subject: Re: Session in Applet??
>
>
> Hi Christian,
> If I get your drift, one thing that you need to do sooner than later is
> separate between client side Java code such as applets and server-side,
> which is your JSP/Servlet. At any case, an Applet can't maintain a session
> if you leave your site. Whenever a page which holds an applet unloads, the
> applet gets unloaded too.
> Maintaining a session is done either by setting a cookie, and then you can
> the cookie's expiration date as need be, or by using URL-Rewriting, which
> maintains sessions only as long as the client hasn't left your site. stick
> to cookies, therefore.
> zm.
>
>
> -----Original Message-----
> From: A mailing list about Java Server Pages specification and reference
> [mailto:[EMAIL PROTECTED]]On Behalf Of Christian Kurze
> Sent: Sunday, December 30, 2001 10:32 PM
> To: [EMAIL PROTECTED]
> Subject: Session in Applet??
>
>
> Hi all,
> I want to use an Applet for communication between the browser and the
> web-server. In the applet there should be a Thread that
> permanently tries to
> read from an ObjectInputStream. A Servlet sends via sendObject()
> Objects to
> all the client-applets.
> My problem: My session of the user might get lost. The applet is startet
> from an JSP which uses a session. Several attributes are bound to it. When
> the user  visits another site of my webapp the session still has to be
> valid. I don't know how tomcat3.2 handles this fact. Is it enough that the
> applet communicates with the server that the session won't get
> lost? If not,
> how could I implement it?
>
> thx in advance
>
> Christian