Associate a file to a servlet session

[senges]

Hi,

for a certain servlet session i want to create some files (images)
which are session specific. When the session is invalid or gets
destroyed i want these files to be deleted.

Anyone has some experience with that issue?

Is there some kind of a session destructor which can notify me when the
session is destroyed so that i can delete the associated files?

What's the best way to associate files/artefacts with a specific
session?

Thanks for any help,
Chris

 

[Ed Kirwan]

Hi,

for a certain servlet session i want to create some files (images)
which are session specific. When the session is invalid or gets
destroyed i want these files to be deleted.

Anyone has some experience with that issue?

Is there some kind of a session destructor which can notify me when the
session is destroyed so that i can delete the associated files?

What's the best way to associate files/artefacts with a specific
session?

Thanks for any help,
Chris

Not sure what the, "Best," way to associate artefacts with sessions is,
but a key question is: how secure do you want it?

I have a servlet which instantiates a Session based on a name and
password entered by the user. I then insert this name/password
combination in the HTTP sent back to the user, and map the name/password
to the session in the servlet.

When the user enters more input, the name/password are sent as fields to
the servlet, which then finds the appropriate Session to process the input.

This is, of course, unsecure.

As for creating files for a particular session, simplest is to create
the filename with a counter which is stepped per session instantiation,
and store this name in the Session itself, thus the correct files are
accessible via the name/password-Session mapping for each session access.

Finally, on servlet initialisation I create a watchdog thread that wakes
up every five minutes and examines every active Session (each session
records the time of its last access). Any session that hasn't been
touched in five minutes is presumed abandoned and so destroyed. In your
case, the Session itself will be told to kill itself, and it can delete
its files.

 

[William Brogden]

Hi,

for a certain servlet session i want to create some files (images)
which are session specific. When the session is invalid or gets
destroyed i want these files to be deleted.

Anyone has some experience with that issue?

Is there some kind of a session destructor which can notify me when the
session is destroyed so that i can delete the associated files?

What's the best way to associate files/artefacts with a specific
session?

Thanks for any help,
Chris

Store all the File references in an object that implements
HttpSessionBindingListener and keep only that reference in the
session - when the session is invalidated for any reason, the
valueUnbound method will be called and you can proceed with
cleanup.

Bill

 

[senges]

thanks a lot,

.... that's a nice way to do it really.

i just started implementing the HttpSessionListener interface which
allows for nice notification about session creation and destruction -
that works for me.

Chris