Collect a numbered series of pages

series_download.pl

#!/usr/bin/env perl

use v5.14;
use warnings;
use autodie qw( :all );
use utf8::all;
use List::Util qw( shuffle );

use WWW::Mechanize;

#use Data::Show;

sub main {
    my $base_url = '';
    my $ua = 'Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.20.25 (KHTML, like Gecko) Version/5.0.4 Safari/533.20.27';
    
    my @initial_numbers = 9997 .. 18428;
    my @keep = [];
    
    foreach my $id (@initial_numbers) {
    my $filename = $id . '.html';
    if (!-e -s $filename) {
      push @keep, $id;
    }
  }
  
    my @page_numbers = shuffle @keep;

    my $mech = WWW::Mechanize->new( 'autocheck' => 1, 'agent' => $ua, );
    
    foreach my $id (@page_numbers) {
        my $filename = $id . '.html';
        $mech->get( $base_url . $filename,
            ":content_file" => $filename );
          say 'Saved '. $filename;
    
          sleep int(rand(15));
          }
}

main() unless caller;

1;