I'm trying to write a very simple multi-threaded spider that can go out and fetch links from a number of pages at once. My basic single threaded script works fine ( everything below the subroutine comment ) when it is it's own script.

However, when I call it as a job from a thread pool, I can't get an response via LWP::UserAgent on my requests. I originally abstracted away the subroutine stuff as it's own package, but that didn't work either ( I thought that might help if there is a scoping error ).

Given that I have no experience with multithreading over than playing around with a few of the modules and making threads print stuff concurently, am I doing something mind-numbingly stupid or is there something worse going on?

Thanks for advice in advance.

#!c:/usr/bin/perl

# CPAN modules
use Thread::Pool;
use LWP::UserAgent;
use HTML::LinkExtor;
use URI::URL;

$pool = Thread::Pool->new(
    {
        optimize => 'cpu',          # default: memory
        do => 'XXX',        # must have
        checkpoint => \&checkpoint,
        frequency => 1000,
        workers => 5,     # default: 1
        maxjobs => 50,     # default: 5 * workers
        minjobs => 5,      # default: maxjobs / 2
    },
);

# Start up some threads
$pool->job( "http://www.yahoo.com" ); 
$pool->job( "http://www.eroticfalconry.com" );
$pool->join;          # wait for all threads to finish

#### subroutines

sub XXX {
    $current_url = @_[0];
    @queue = ();
    
    while( $current_url ne "" ){
        @links = get("$current_url" );
        print "links in url\n********************\n";
        print join("\n", @links), "\n";
        push(@queue,@links);
        #print "links in queue\n********************\n";
        #print join("\n", @queue), "\n";
        $current_url = pop(@queue);
        print ">>>>new url=$current_url\n"; #this is where we go next
    }
}

my $p = HTML::LinkExtor->new(\&callback);
my @links = ();

# Set up a callback that collect links
sub callback {
   my($tag, %attr) = @_;
   return if $tag ne 'a';  # we only look closer at <a ...>
   push(@links, values %attr);
}

sub get {
  $url = "@_[0]";  
  print "Entering html::getlinks, url=$url\n";
  my $ua = LWP::UserAgent->new;
    $res = $ua->request(HTTP::Request->new(GET => $url), sub {$p->pars
+e($_[0])});
    $base = $res->base; # Expand all URLs to absolute ones
    @links = map { $_ = url($_, $base)->abs; } @links;
    return @links;
}

$version = 1;
[download]

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