The problem with the lack of output is almost definitely a buffering issue. Try making the request using wget or with telnetand see exactly what is being returned.

This code demonstrates that the logic works, and it outputs a dot every 10 seconds, but only forces the user to wait a maximum of one second more than the process would have taken anyway:

#!/usr/bin/perl
use strict;
use warnings;
use threads;
use threads::shared;

# set a shared value of TRUE for running the progress bar
my $keepRunningProgressBar : shared = 1;

# Set the progress bar running indefinitely
my $progressBar = threads->create(
    sub { 
        my $i = 0;
        while ($keepRunningProgressBar == 1) {
            if ($i++ % 10 == 0) {
                print ".\n";
            }
            sleep(1);
        }
    }
); 

# Now do stuff in the work thread
my $threadForSpidering = threads->new(
    sub {
        my $i = 0; 
        while ($i++<5) {
            print "Working\n"; 
            sleep 1;
    }});

#The work thread finished
$threadForSpidering->join;

#And tells the progress bar to stop running
$keepRunningProgressBar = 0;
$progressBar->join;

print "\nGOT HERE\n";
[download]

#!/usr/bin/perl
use strict;
use warnings;
use threads;
use threads::shared;

# set a shared value of TRUE for running the progress bar
my $keepRunningProgressBar : shared = 1;

# Set the progress bar running indefinitely
my $progressBar = threads->create(
    sub { 
        while ($keepRunningProgressBar == 1) {
            print ".\n";
        sleep(10);
    }
); 

# Now do stuff in the work thread
# Now do stuff in the work thread
my $threadForSpidering = threads->new(
    sub {
        my $i = 0; 
        while ($i++<5) {
            print "Working\n"; 
            sleep 1;
    }});

#The work thread finished
$threadForSpidering->join;

#And tells the progress bar to stop running
$keepRunningProgressBar = 0;

$progressBar->kill('KILL')->detach();

print "\nGOT HERE\n";
[download]