Re: calling one cgi script from another

[jimt]

fork is your friend. Fork off a copy of your script and have it do whatever it needs to do. A fork + exec may be better, if you want to do something else in its place.

Caveat - if you're running in a mod_perl environment, you're gonna fork your entire apache process, which has memory overhead concerns among other issues that I always seem to forget. Filehandles, is it? Only do it here if you absolutely have to. CGIs? No sweat.

From there, just proceed as before - refresh the user back to some other page, and when your forked process completes, give it someway to flag its being finished. Touch a file, update a row in a database, something. Something that can be a quick and simple check for the front end to do.

To show the user the changes, there are several approaches - have 'em constantly click a button ("Am I done yet?") to refresh the page and display results if appropriate. Or bring up a "loading..." screen that watches for the update and refreshes when it gets it (note that this blocks the user), or do something fancy and ajaxy that autorefreshes (or gives a refresh button) when the data is actually there.

[Anonymous Monk]

OK, I'l give that a try. Thanks for your help. (I don't usually accept being told to fork off, but I suppose this time it's ok!!)

[Anonymous Monk]

I've been reading up on this and have implemented the fork:


if ($pid = fork) { 
print "I am parent\n"; 
} elsif (defined $pid) { 
print "I am child\n"; 
sleep 5; 
print "Child is done\n"; 
} else { 
die "Major error: $!"; 
} 
print "PID: $$\n";

However I need the child to run in the background, for the browser to be freed up on printing the parent. Can anyone point me in the right direction, please?

[derby]

merlyn has an article on this topic.

[Anonymous Monk]

Actually, I don't want to keep an eye on it - I just need ti to carry on until it's finished.

Effectively I need system "long_running_code with parameters &"; but not in the shell as I need to pass arguments