How to prevent a web client from timing out

[Jeff Bauer]

Alexis Iglauer wrote:
> The job is different every time, so a cron solution 
> wouldn't work.  The problem is that when the client 
> times out the server kills the python process doing 
> the number crunching

I didn't suggest cron.  (Someone else may have.)

You can basically have a separate process already 
running, waiting for a number-crunching request.
It is independent of the client, so if the client
times out, nothing happens to the long-running 
process.

Assume the long-running process (LRP) is threaded,
and it can report back the status of the operation 
when your client requests it.  

Scenario:

1. Client (cgi script) submits a number-crunching 
request to LRP.

2. LRP responds back to client, "I'm working
on it.  Press HERE to check on status."

3. User presses HERE button and another cgi script
calls the LRP, which replies, "Gimme a minute,
will ya?  Jeez."

4. User presses HERE button again.  Cgi script
calls the LRP which has now finished the calculation.
It responds, "The answer is 42."

> So how do I stop apache from killing the process?  

Because Apache didn't launch the process, Apache
won't kill the process.  You do the LRP independent
of Apache.

> How well does xmlrpc work in the real world?

I don't know about the "real" world, but I've
created an artificial world where it works pretty
well.  

But for the technique described above, you don't 
*have* to use xmlrpc. Any similar technique (e.g. 
DOPY, Fnorb, ILU) should also prove satisfactory.

Jeff Bauer
Rubicon Research