URL::List - Helper class for creating distributed lists of URLs based on their host name, domain name or TLDs.
Version 0.13
use URL::List;
my $list = URL::List->new;
$list->add( 'http://www.google.com/' );
$list->add( 'http://www.bbc.co.uk/' );
# or
my $list = URL::List->new(
allow_duplicates => 1, # default false
urls => [ ... ], # arrayref of URLs
);
my $distributed_by_hosts = $list->distributed_by_host;
# $VAR1 = {
# 'www.google.com' => [
# 'http://www.google.com/',
# ],
# 'www.bbc.co.uk' => [
# 'http://www.bbc.co.uk/',
# ],
# };
my $distributed_by_domains = $list->distributed_by_domain;
# $VAR1 = {
# 'google.com' => [
# 'http://www.google.com/',
# ],
# 'bbc.co.uk' => [
# 'http://www.bbc.co.uk/',
# ],
# };
my $distributed_by_tlds = $list->distributed_by_tld;
# $VAR1 = {
# 'com' => [
# 'http://www.google.com/',
# ],
# 'co.uk' => [
# 'http://www.bbc.co.uk/',
# ],
# };
my $urls = $list->all; # All the URLs are still there, so use this...
$list->clear; # ...to clear the list.
URL:List is a module which helps you with distributing a list of URLs "evenly" based on the URLs' host name, domain name or TLD (top-level domain).
This can be useful for crawlers, ie. giving out a list of URLs within specific hostnames, domain names and/or TLD names to different workers.
Returns an instance of URL::List.
Takes one optional parameter, 'allow_duplicates', which is default 0. By setting it to true (1), URL::List will not filter out duplicate articles.
Add a URL to the list. $url can be an array reference of URLs.
Returns an array reference of all the URLs in the list.
Returns the number of URLs in the list, including potential duplicates, depending on the 'allow_duplicates' setting.
Clears the URL list.
An alias for clear.
Returns a hash reference of all the possible distributions.
This method should not be used directly. Instead, the distributed_by_* methods should be used.
Returns a hash reference where the key is the host name, like "www.google.com", and the value is an array reference to the host name's URLs.
Returns a hash reference where the key is the domain name, like "google.com", and the value is an array reference to the domain name's URLs.
Returns a hash reference where the key is the top-level domain name, like "com", and the value is an array reference to the top-level domain name's URLs.
Returns "blocks" of URLs distributed by their host/domain/TLD, i.e. an array reference of array references containing URLs distributed as evenly as possible;
my $list = URL::List->new(
urls => [qw(
http://www.businessinsider.com/1.html
http://www.businessinsider.com/2.html
http://www.businessinsider.com/3.html
http://www.engadget.com/1.html
http://www.engadget.com/2.html
http://www.engadget.com/3.html
http://www.engadget.com/4.html
http://www.independent.co.uk/1.html
http://www.independent.co.uk/2.html
http://www.pcmag.com/1.html
http://www.pcmag.com/2.html
http://www.pcmag.com/3.html
http://www.technologyreview.com/1.html
http://www.technologyreview.com/2.html
http://www.technologyreview.com/3.html
http://www.technologyreview.com/4.html
http://www.zdnet.com/1.html
http://www.zdnet.com/2.html
http://www.zdnet.com/3.html
)],
);
# $list->blocks_by_host = [
# [qw(
# http://www.businessinsider.com/1.html
# http://www.engadget.com/1.html
# http://www.independent.co.uk/1.html
# http://www.pcmag.com/1.html
# http://www.technologyreview.com/1.html
# http://www.zdnet.com/1.html
# )],
#
# [qw(
# http://www.businessinsider.com/2.html
# http://www.engadget.com/2.html
# http://www.independent.co.uk/2.html
# http://www.pcmag.com/2.html
# http://www.technologyreview.com/2.html
# http://www.zdnet.com/2.html
# )],
#
# [qw(
# http://www.businessinsider.com/3.html
# http://www.engadget.com/3.html
# http://www.pcmag.com/3.html
# http://www.technologyreview.com/3.html
# http://www.zdnet.com/3.html
# )],
#
# [qw(
# http://www.engadget.com/4.html
# http://www.technologyreview.com/4.html
# )],
# ],
This is useful if you want to crawl many URLs, but also want to pause between each visit to host/domain/TLD;
my $list = URL::List->new( urls => [...] );
foreach my $urls ( @{$list->blocks_by_domain} ) {
# get $urls in parallel, you will only visit each domain once, or you
# can delegate $urls to other workers (crawlers) to spread load etc.
sleep( 5 ); # let's be nice and pause
}
Copyright 2012-2017 Tore Aursand.
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