Now when I run them using the piped open from the OP (original post? - still learning...) I get back to my original problem, the calling script will not print any of the pipe's output until the pipe command has completed.

I look at your first example though, do you think I am barking up the wrong tree to think the Perl caller is the problem? I have access to the java files, I will try tinkering with their output buffering and see if that yields any results.

Thanks!

I'm not a cgi person, but there are various things that could be causing the symptoms you are describing. You need to determine where the delays are occuring.

If the java program produces a steady stream of output when invoked via the command line, it probably isn't the source of your problem.

You could confirm that it isn't your perl cgi script, by invoking it directly from the command line and watching what happens. If it also produces a steady stream when invoked this way, then there are a couple of other places where the problem could lie. Eg.

• Depending upon the browser involved, and the html you are outputting, the browser could be refusing to format and display what it has received, until it gets the end tag for one or more elements.

  Some (maybe all?) browsers refuse to format tables until they know how many or how big the rows are.

  You could probably verify if this is the problem, by temporarily switching the content type header to text/plain. That should cause the browser to display the html and content as it arrives rather than waiting until it knows how to format it.

  If this is the problem, you may be able to avoid it by switching to using <p> or <br> formatting rather than (for example) a table.

• Depending upon the web server you are using, it may be buffering the output until it detects the end of the cgi task.

  A quick way of checking this would be to run the cgi script to completion, from the command line, having redirected stdout to a file. Then substitute a simple cgi script that slurps the file in one chunk, prints it to the browser in one chunk, and then sleeps for 5 minutes before exiting.

  If you see that output in the browser straight away, then the delay is in the browser. If you don't see the output for 5 minutes, the delay is in the server/cgi interface.

If you supply a better picture of what you are doing--what server, browser, html formatting etc--you are using, then one of the many experienced CGI people here will be probably be able to offer you better ways of determining the source of your problem, and probably a solution to it.

Ultimately, unless your web server is dedicated to running just this task, or just a few low-demand tasks, it's generally not a good idea to have a cgi script that takes hours to run. The usual solutions to this involve forking, but they generally don't work under Win32 unless you are also using cygwin. I do have an alternative to that, but you would still need to fix the above problem(s) first.

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

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OK, Apache 2.2 server, either Mozilla or IE browser, and as far as the html formatting that goes on, the page in question will print a very simple header, then its basically this loop, from the OP:

$| = 1;
open(JAVA, "java_command_stuff |") or die ...;
while(<JAVA>){
   my $line = $_;
   print "$line<br>\n";
}
close JAVA;
[download]

After which I close out the html tags and the script ends.

I tried switching the header to text/plain but still don't get any output until task is complete.

Just an FYI, most all of the tests this runs, will complete in just a matter of seconds. There is just one pesky test case here that is running for so long, but I would like to be able to handle more 'long duration' cases in the future so I'm trying to work this out now...

thanks