how to dispose session variables automatically

[Andy Fish]

Hi,

I have some objects that implement IDisposable and they in turn need to
dispose of other objects (Only managed resources are being used).

My objects are held in the HTTP session. Is there a way to get these to be
Disposed properly when the session ends?

I guess I could use the session_end event but apparently it's not a good
idea to rely on this because it might not be called in all circumstances.
Also it's not possible to call dispose of another managed object from inside
a finalizer so I can't do it there.

is there an accepted best practice for this?

Andy

 

[Anthony Jones]

Hi,

I have some objects that implement IDisposable and they in turn need to
dispose of other objects (Only managed resources are being used).

My objects are held in the HTTP session. Is there a way to get these to be
Disposed properly when the session ends?

I guess I could use the session_end event but apparently it's not a good
idea to rely on this because it might not be called in all circumstances.
Also it's not possible to call dispose of another managed object from inside
a finalizer so I can't do it there.

is there an accepted best practice for this?

Yeah don't store IDisposable objects in the session

Seriously though first consider whether you really need to be holding
disposable types. If you need to hold these types it will be because they
internally hold something disposable can those internal references be
disposed before the end of a request?

How unreliable do you think Session_End is? If occasionally it doesn't run
is it a disaster that sometimes things have to wait until a GC run to be
tidy up? After all its likely the session has been hanging around idle for
a while anyway.

 

[Hans Kesting]

After serious thinking Anthony Jones wrote :

How unreliable do you think Session_End is?

Apparently if you use something other than InProc storage for the
session, the Session_End is never called.

Hans Kesting

 

[Anthony Jones]

After serious thinking Anthony Jones wrote :

Apparently if you use something other than InProc storage for the
session, the Session_End is never called.

Umm.. ok. are you using Out of Proc storage?

Is it possible to store objects that truely need to be disposed (due to
using an unmanaged resource) in an out-of-proc store?

There are three nominal ways a session ends, it times out due to being idle,
a deliberate user action or if its inproc the process is a victim of
recycling.

If it ends on idle does it really matter that objects aren't immediately
disposed?
If the process terminates naturally then the objects are dropped and any
unmanaged resources would do what they naturally do when a process ends.

If a deliberate user action then code on the server is needed to bring that
about, you could place code there to handle the disposing. Thats pretty
messy.

Like I said you really want to avoid disposable objects being stored in the
session in the first place