[Zope] timeout

[Richard Barrett]

At 10:14 01/02/2002 +0100, Ulrich Wisser wrote:
>Hi,
>
>one of my reports takes more than 5 minutes.
>This causes Zope to produce a timeout. Although
>it is no good idea to let the user wait that
>long, I would prefer to show a result anyway.
>How can I set the timeout?

The problem is potentially more than just Zope. Lengthy delays may lead to 
the browser end disconnecting the TCP connection.

Then there is the very real problem of user boredom. On a loaded server 
with lengthy delays, users are prone to hitting the stop and reload buttons 
on their browser as they imagine something has gone wrong with the first 
attempt because of the response delay.

I do not think that Zope will kill a running thread because the browser it 
is responding to has dropped the connection over which the request was 
sent. When the application completes its work and returns to zope's 
response code, zope can only drop the output in the bit bucket if the 
connection has been dropped by the browser. The consequence is that the 
server can become clogged with process generating answers that nobody (now) 
wants to read.

I have certainly seen a case with Apache using a cgi scipt to access a 
database where an impatient user single-handedly mounted a very effective 
denial of service attack, with the active cooperation of the cgi script 
concerned.

If it takes a variable, lengthy period to generate a response you might be 
better changing your approach. One approach is to spawn a detached process 
and then immediately return a page with a link on it to a status script 
that can check the spawned process' status. The status script then returns 
either an informative message plus a link back to itself if the spawned 
process hasn't completed, or returns the report if it has the spawned 
script has run to completion and exited. With Javascript you could get even 
fancier in handling the retrying.

>Thanks
>
>Ulrich
>
>
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