As you see, originally I posted a piece of pseudo-code. It described logic. The algorithm. I used perl syntax and made the block into a sub to help you with the actual implementation.

Below is a piece of REAL executable code in realworld perl. It actually crawls the web (provide it with urls in command-line). And I --you, sorry.

Just run it as a separate script, no need to "put it into" your code. 

#/usr/bin/perl -w
use strict;

use LWP::RobotUA;
use HTML::SimpleLinkExtor;

use vars qw/$http_ua $link_extractor/;

sub crawl {
    my @queue = @_;
    my %visited;

    while(my $url = shift @queue) {
        next if $visited{$url};

        my $content = $http_ua->get($url)->content;
        # do useful things with $content
        # for example, save it into a file or index or whatever
        # i just print the url
        print qq{Downloaded: "$url"\n};

        push @queue,
        do { $link_extractor->parse($content); $link_extractor->a };
        $visited{$url} = 1;
    }
}

$http_ua = new LWP::RobotUA theusefulbot => 'bot@theusefulnet.com';
$link_extractor = new HTML::SimpleLinkExtor;

crawl(@ARGV);

[download]

In reply to Re: Re: Cutting Out Previously Visited Web Pages in A Web Spider by kappa
in thread Cutting Out Previously Visited Web Pages in A Web Spider by mkurtis

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