Ok this is my (i'm sure highly inefficient and embarrisingly limited) perl code for a web robot;) I have missed lots and lots out to try not to bore people with the details. It works fine for ages, but just crashes out when looking up certain urls... weird.

#!/usr/bin/perl -w
########################################################
# Program written by Tom Freeman 2003
# -----------------------------------
# Purpose: To collect information about the technologies
# being used on websites, particularly client side 
# technologies. As well as the server the sites are using.
#
# Improvements
#  v1.8: Added support for the META exclusion protocol
# i.e. <META name="ROBOTS" content="NOINDEX, NOFOLLOW">
#
# v3.3: now retains a list of new domains on disk in
# domains.dat file
#
########################################################

require LWP::Parallel::UserAgent;
use HTTP::Request;
#use LWP::Debug qw(+); # display tons of debugging messages. See 'perl
+doc LWP::Debug'
use URI;
use URI::URL;
use HTML::LinkExtor;
use LWP::Simple qw(get);
use Time::SoFar qw( runtime runinterval figuretimes );
use Fcntl;
use DBI;

my $domainsfile = 'domains.dat';

####### VARIABLES ######################################
my $pua = LWP::Parallel::UserAgent->new();
$pua->in_order  (1);  # handle requests in order of registration
$pua->duplicates(0);  # ignore duplicates
$pua->timeout   (2);  # in seconds
$pua->redirect  (1);  # follow redirects

my @domains=();
push @domains, 'http://www.bbc.co.uk'; #load first value onto the doma
+ins array

my $pass_counter = '0';
$num_domains = scalar @domains;

while ($num_domains > '0') { # Start Loopy Code

  ######## Load up the old domains file from disk ######
  open DOMAINSFILE, "< $domainsfile" || print "Failed to open logfile 
+for writing: $!";
  @domains = (<DOMAINSFILE>);
  close(DOMAINSFILE);
  ######################################################

  $pass_counter++;

  my @selected_domains=();
  while (scalar @selected_domains <= 10) {
    my $new_domain = shift @domains;
    my $visited = &checkExists($new_domain);
    if (!$visited) {
      push @selected_domains, $new_domain;
    }
  }
  my $reqs = [
    HTTP::Request->new('GET', $selected_domains[0]),
    HTTP::Request->new('GET', $selected_domains[1]),
    HTTP::Request->new('GET', $selected_domains[2]),
    HTTP::Request->new('GET', $selected_domains[3]),
    HTTP::Request->new('GET', $selected_domains[4]),
    HTTP::Request->new('GET', $selected_domains[5]),
    HTTP::Request->new('GET', $selected_domains[6]),
    HTTP::Request->new('GET', $selected_domains[7]),
    HTTP::Request->new('GET', $selected_domains[8]),
    HTTP::Request->new('GET', $selected_domains[9]),
  ];

  foreach my $req (@$reqs) {
    if ($req->url) {
      print "Registering ".$req->url."\n";
      if ( my $res = $pua->register ($req) ) {
        print STDERR $res->error_as_HTML;
      }
    }
  }
  $entries = $pua->wait();

  foreach (keys %$entries) {
    my $res = $entries->{$_}->response;
    my $domain = $res->request->url;
    if ($res->is_success) {
      # Do lots of interesting stuff with the 
      # content and write out to the database
    }
  }
  $num_domains = scalar @domains; # get the size of array
  ######### Write out the new domains file ######
  open DOMAINSFILE, "> $domainsfile" || print "Failed to open logfile 
+for writing: $!";
  foreach my $domain (@domains) {
    print DOMAINSFILE "$domain\n";
  }
  close(DOMAINSFILE);
  ###############################################
  (@domains)=();
  undef %$entries;

}
[download]

I hope this isn't too much code to annoy people, i'd be interested to hear any of your thoughts, ideas and comments?

Many Thanks,
Tom

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