[Twisted-web] _nevow_carryover_

Andrea Arcangeli andrea at cpushare.com
Sat May 14 05:56:06 MDT 2005

Hello Donovan,

On Thu, May 12, 2005 at 11:21:04AM -0700, Donovan Preston wrote:
> A very good point, although the chances of two forms being submitted  
> simultaneously and one redirected render getting the other redirected  
> render's hand is impossibly small. The IHand should only be available  

This is generally true but every race will trigger eventually, so I'd
suggest not make this assumptions in the core of the server. This would
be a problem especially if tons of users are given the same account
credentials to access a part of the website.

The only problem I have with carryover personally is the lack of
timeout. Each carryover should have a timestamp and periodically there
should be a scan of all carryovers (with some volountary preemption in
between the scan, so perhaps done with a timer with 0 timeout to avoid
hanging twisted for an extended period of time). Too old carryovers
should be deleted from the hash. I'd suggest to keep the timeout
configurable for the app (like the session timeout is also
configurable), so depending on the load and memory of the system one can
tune it. A default to the same default of the session timeout sounds

The weird URL of the carryover is fine with me, this will never be a
robot posting a form and saving the wierd filename. The weird url for
the session start instead is a problem, because wget can be used there
so I removed it and apparently it didn't break anything ;).


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