[Twisted-web] _nevow_carryover_

Tommi Virtanen tv at twistedmatrix.com
Thu May 12 05:51:54 MDT 2005

Donovan Preston wrote:
>> Can someone tell me what the _nevow_carryover_ argument that gets
>> added to URLs as part of form processing is for? Is there any way of
> This is used to implement the formless "IHand" when no guard session  or
> cookie-based session is present (and it is always used regardless  of
> whether they are present).

Actually, that's not true. Carryover is used even when we have a

> 2) If the user actually is returning values from the autocallable,  and
> is actually looking for the result in the IHand of the next  request:
> Check to see if there is a guard session. If so, store the  hand there
> for the duration of the redirect.

That won't really work -- I've had multiple browser windows open
belonging to the same session many times, having just one IHand per
session just isn't going to work.

> 3) Finally, if people ARE returning results from autocallables, AND  ARE
> NOT using guard AND are still annoyed with _nevow_carryover_, I  have an
> idea which involves putting the mini-session key in the <form 
> action=""> instead of the redirect. Since users only see the action  url
> during the time it takes their browser to redirect, and the  redirected
> request can pull the mini-session key out of the referrer,  this would
> work.

..you assume referrers work reliably :(

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