> > I think it'd be nice to have session created explicitly inside a "WITH" > statement block so that users create sessions only when they want. But I > don't know if it's feasible because I suspect sessions are created > automatically and passed into the exec environment, and it appears sessions > are used to keep track of a few things in web2py. > > In other words, the web2py's way is sessions are created by default and > optionally "forget". But it *might* be better if sessions are not created > by default and users are given an easy method to create sessions. >
Right, there is a small performance hit given that web2py automatically loads the session at the start of every request. You also suggested, though, that the application logic for turning off sessions when not needed would somehow be more complex and difficult than it would be if instead you had to turn on sessions when you need them, and it's not clear to me that that is the case. In web2py, to simulate the latter, I think you can just do session.forget(response) at the beginning of every request (early in first model file), and then do session.connect(request, response) at some later point in the code when you do need to read/write the session. So, your application logic shouldn't really need to be any more complex in web2py. Also, note, web2py does not write to the session file on requests in which the session does not change, so there is no reason to forget/unlock the session merely to avoid unnecessary file writing. The only reason to unlock the session file is to prevent one request from a given user from blocking other concurrent requests from that same user -- and this would generally only be an issue if the user is loading a page with multiple simultaneous Ajax requests that don't use the session. Note, if the multiple Ajax requests actually do need the session, then you do in fact want them to block each other because otherwise you could introduce race conditions with the session. Anthony --
