New SessionStore backed by HttpSession

[coopernurse]

Hi,

On the noir group we've been discussing Google App Engine deploys which are clustered. We agreed it would be useful to have a ring SessionStore that targeted the HttpSession provided by the servlet container. The storage semantics of the session would consequently be delegated to the container, which may store it in a db, replicate it, etc.

You'll see that I'm not using the ring session-key, as the session binding will already be scoped to the current request.

Implementation is provided + tests. Java serialization is used. I did some basic perf tests, and they seem fine. Sub 1ms serialization times for sessions of 10kb on my MBP.

Discussion of the general feature here:

https://groups.google.com/forum/#!topic/clj-noir/jM4SJb8NsDU

thank you,

-- James

[weavejester]

Hi, sorry for the delay in responding. This past week has been really busy!

I'm in two minds whether to include this into Ring, or to suggest first releasing it as a separate library. It seems a very useful session store for hosts like GAE and any existing load-balanced Java infrastructure, which is likely to cover a not-insignificant proportion of Ring-based applications.

On the other hand, I'd like to limit new functionality added to Ring before version 1.0. Another problem with this middleware is that it's placed in ring-core, but requires that Ring be run inside a Java servlet engine. Perhaps a better place would be ring-servlet, but it would also do well as a stand-alone library.

I think I'm going to err on the side of caution and suggest that this is first released as a third-party library, with an eye to consider incorporating it into Ring 1.1.0 if it proves to be a popular piece of middleware.