Creating Specialized Session State Store

[Michael O'Brien]

I'm trying to hook in a specialized state store server into ASP.NET.

I understand I can create a HttpModule and hook the events
OnAcquireState and OnReleaseState. So far so good.

But, it seems that the framework owns the HttpSessionStat e instance
(HttpContext.Se ssion) and so my state store module must use the Add,
Remove and Clear methods to interact with the store. ie. on Acquire, I
need to call HttpSessionStat e.Add to add all the persisted state
variables into HttpSessionStat e and on Release, I need to persist the
state from HttpSessionStat e back to my store. To do this I can just
use the indexer in HttpSessionStat e.

But this is going to be slow as I will be saving and restoring the
entire session state. If the session state is very large, I wan't to
only persist those items that have changed. I could keep a copy and
compare what has changed, but that will be 2x the session data and is
also an overhead.

What I'd really like is a lower level interface so that I could only
save session state items that have changed and not have to serialize
the entire state on Release. Since HttpSessionStat e owns the in-memory
session state dictionary, I can't see how I can do this. I'd really
like to create my own HttpsessionStat e instance and control every
set/get to the HttpSessionStat e. To do this I need to set the instance
pointer in HttpContext. I'd like to do this in my module's
BeginRequest event. But, the problem is there is no SetSession method
in HttpContext to use.

Any ideas ?