On Sun, 29 Sep 2002 16:40:07 +0200, [EMAIL PROTECTED] (Octavian Rasnita)
wrote:
>I want to make a script that is activated from a browser but it might take a
>long time to send all the messages using the Net::SMTP.
>
>So I think that it could be a good idea to make a background process to run
>it.
>
>Can you give me some hints about how I should use the fork, to run the
>process in background?
Your biggest problem is to close the pipes to apache from the forked
children, else your clients will see their browser's hang.
Merlyn has a good column on this at www.stonehenge.com column 20.
Here is a simple example to demonstrate the problem.
Make up some long process to test this with, like while(1){sleep(1)}
Then try running it as a cgi script with and without the line which
closes STDOUT, STDIN, and STDERR. With it commented out,
your browser will hang.
##############################################################
#!/usr/bin/perl
use warnings;
use strict;
$| = 1; # need either this or to explicitly flush stdout, etc.
# before forking
print "Content-type: text/plain\n\n";
print "Going to start the fork now\n";
fork && exit;
#try running with the following line commented out
close STDOUT;close STDIN;close STDERR;
exec('./fork-long-process-test-process') || warn "funniness $!";
#if you use system here, instead of exec, the parent process
#hangs around for child to exit, even though the cgi exits.
#############################################################
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