Hi

This is my first attempt at a perl program that does anything vaguely useful - it is a web crawler that currently just prints out the urls that it visits, but may later look for some specific content. Some of the code I pinched from an example program. The problem is that it uses up 2Gb of memory in about 10 minutes and I cannot figure out why this is. I have probably done something fundamentally wrong. Can anyone spot an obvious problem, or offer ideas of how to troubleshoot this? Thanks.

Oh, the usage is basically "./crawler.pl www.mysite.com mysite.com" where the second argument restricts the links it follows to avoid crawling sites other than the target. 

#!/usr/bin/perl

use strict;
use warnings;

use LWP::UserAgent;
use HTML::LinkExtor;
use URI::URL;

my $site = shift @ARGV;
my $domain = shift @ARGV;
my $firsturl = "http://$site";
my $ua = LWP::UserAgent->new;
my @links = ();
my @newlinks = ();
my @visited = ();
my $newlink = "";
my $link = "";
push (@links, $firsturl);

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

# Make the parser
my $p = HTML::LinkExtor->new(\&callback);

# The main loop
MAIN: foreach my $url (@links) {
    # Skip if we have been here before        
        foreach my $inside (@visited) {
        #print "skipping $url\n" if $url eq $inside;
                next MAIN if $url eq $inside;
        }

    # Request document and parse it as it arrives
    print "visiting $url\n";
    my $res = $ua->request(HTTP::Request->new(GET => $url),
                      sub {$p->parse($_[0])});

    # Remember that we have visited this url
    push (@visited, $url);

    # Expand all URLs to absolute ones
    my $base = $res->base;
    @newlinks = map { $_ = url($_, $base)->abs; } @newlinks;

    # Reduce the links to only ones in our domain
    foreach $newlink (@newlinks) {               
            if ($newlink =~ /$domain/) {
                        push (@links, $newlink);
        }
    }   
}

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In reply to Newbie memory leak by memwaster

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