The document discusses practical web scraping using the Web::Scraper module in Perl. It provides an example of scraping the current UTC time from a website using regular expressions, then refactors it to use Web::Scraper for a more robust and maintainable approach. Key advantages of Web::Scraper include using CSS selectors and XPath to be less fragile, and proper handling of HTML encoding.

1. Practical Web Scraping with Web::Scraper Tatsuhiko Miyagawa [email_address] Six Apart, Ltd. / Shibuya Perl Mongers YAPC::Europe 2007 Vienna

4. abbreviation Acme::Module::Authors Acme::Sneeze Acme::Sneeze::JP Apache::ACEProxy Apache::AntiSpam Apache::Clickable Apache::CustomKeywords Apache::DefaultCharset Apache::GuessCharset Apache::JavaScript::DocumentWrite Apache::No404Proxy Apache::Profiler Apache::Session::CacheAny Apache::Session::Generate::ModUniqueId Apache::Session::Generate::ModUsertrack Apache::Session::PHP Apache::Session::Serialize::YAML Apache::Singleton Apache::StickyQuery Archive::Any::Create Attribute::Profiled Attribute::Protected Attribute::Unimplemented Bundle::Sledge capitalization Catalyst::Plugin::JSONRPC Catalyst::View::Jemplate Catalyst::View::JSON CGI::Untaint::email Class::DBI::AbstractSearch Class::DBI::Extension Class::DBI::Pager Class::DBI::Replication Class::DBI::SQLite Class::DBI::View Class::Trigger Convert::Base32 Convert::DUDE Convert::RACE Date::Japanese::Era Date::Range::Birth Device::KeyStroke::Mobile Dunce::time Email::Find Email::Valid::Loose Encode::JavaScript::UCS Encode::JP::Mobile Encode::Punycode File::Find::Rule::Digest Geo::Coder::Google HTML::Entities::ImodePictogram HTML::RelExtor HTML::ResolveLink HTML::XSSLint HTTP::MobileAgent HTTP::ProxyPAC HTTP::Server::Simple::Authen IDNA::Punycode Inline::Basic Inline::TT JSON::Syck Kwiki::Emoticon Kwiki::Export Kwiki::Footnote Kwiki::OpenSearch Kwiki::OpenSearch::Service Kwiki::TypeKey Kwiki::URLBL Log::Dispatch::Config Log::Dispatch::DBI Mac::Macbinary Mail::Address::MobileJp Mail::ListDetector::Detector::Fml MSIE::MenuExt Net::DAAP::Server::AAC Net::IDN::Nameprep Net::IPAddr::Find Net::YahooMessenger NetAddr::IP::Find PHP::Session plagger Plagger POE::Component::Client::AirTunes POE::Component::YahooMessenger Template::Plugin::Clickable Template::Plugin::Comma Template::Plugin::FillInForm Template::Plugin::HTML::Template Template::Plugin::JavaScript Template::Plugin::MobileAgent Template::Plugin::Shuffle Template::Provider::Encoding Term::Encoding Term::TtyRec Text::Emoticon Text::Emoticon::GoogleTalk Text::Emoticon::MSN Text::Emoticon::Yahoo Text::MessageFormat Time::Duration::ja Time::Duration::Parse Web::Scrape WebService::Bloglines WebService::ChangesXml WebService::Google::Suggest WWW::Baseball::NPB WWW::Blog::Metadata::MobileLinkDiscovery WWW::Blog::Metadata::OpenID WWW::Blog::Metadata::OpenSearch WWW::Cache::Google WWW::OpenSearch XML::Atom XML::Atom::Lifeblog XML::Atom::Stream XML::Liberal

6. http://code.sixapart.com/

9. Web pages are built using text-based mark-up languages ( HTML and XHTML ), and frequently contain a wealth of useful data in text form. However, most web pages are designed for human consumption, and frequently mix content with presentation. Thus, screen scrapers were reborn in the web era to extract machine-friendly data from HTML and other markup. http://en.wikipedia.org/wiki/Screen_scraping

10. Web pages are built using text-based mark-up languages ( HTML and XHTML ), and frequently contain a wealth of useful data in text form. However, most web pages are designed for human consumption, and frequently mix content with presentation. Thus, screen scrapers were reborn in the web era to extract machine-friendly data from HTML and other markup. http://en.wikipedia.org/wiki/Screen_scraping

18. <td>Current <strong>UTC</strong> (or GMT/Zulu)-time used: <strong id=&quot;ctu&quot;>Monday, August 27, 2007 at 12:49:46</strong> <br />

19. <td>Current <strong>UTC</strong> (or GMT/Zulu)-time used: <strong id=&quot;ctu&quot;>Monday, August 27, 2007 at 12:49:46</strong> <br /> > perl -MLWP::Simple -le '$c = get(&quot;http://timeanddate.com/worldclock/&quot;); $c =~ m@<strong id=&quot;ctu&quot;>(.*?)</strong>@ and print $1' Monday, August 27, 2007 at 12:49:46

21. WWW::MySpace 0.70

22. WWW::Search::Ebay 2.231

23. WWW::Mixi 0.50

29. <span class=&quot;message&quot;>I &hearts; Vienna</span> > perl –e '$c =~ m@<span class=&quot;message&quot;>(.*?)</span>@ and print $1' I &hearts; Vienna

30. <span class=&quot;message&quot;>I &hearts; Vienna</span> > perl –MHTML::Entities –e '$c =~ m@<span class=&quot;message&quot;>(.*?)</span>@ and print decode_entities ($1)' I ♥ Vienna

31. <span class=&quot;message&quot;> ウィーンが大好き！ </span> > perl –MHTML::Entities –MEncode –e '$c =~ m@<span class=&quot;message&quot;>(.*?)</span>@ and print decode_entities( decode_utf8 ($1))' Wide character in print at –e line 1. ウィーンが大好き！

36. XPath <td>Current <strong>UTC</strong> (or GMT/Zulu)-time used: <strong id=&quot;ctu&quot;>Monday, August 27, 2007 at 12:49:46</strong> <br /> use HTML::TreeBuilder::XPath; my $tree = HTML::TreeBuilder::XPath->new_from_content($content); print $tree->findnodes ('//strong[@id=&quot;ctu&quot;]') ->shift->as_text; # Monday, August 27, 2007 at 12:49:46

40. CSS Selectors <td>Current <strong>UTC</strong> (or GMT/Zulu)-time used: <strong id=&quot;ctu&quot;>Monday, August 27, 2007 at 12:49:46</strong> <br /> use HTML::TreeBuilder::XPath; use HTML::Selector::XPath qw(selector_to_xpath); my $tree = HTML::TreeBuilder::XPath->new_from_content($content); my $xpath = selector_to_xpath &quot;strong#ctu&quot;; print $tree->findnodes($xpath)->shift->as_text; # Monday, August 27, 2007 at 12:49:46

41. Complete Script #!/usr/bin/perl use strict; use warnings; use Encode; use LWP::UserAgent; use HTTP::Response::Encoding; use HTML::TreeBuilder::XPath; use HTML::Selector::XPath qw(selector_to_xpath); my $ua = LWP::UserAgent->new; my $res = $ua->get(&quot;http://www.timeanddate.com/worldclock/&quot;); if ($res->is_error) { die &quot;HTTP GET error: &quot;, $res->status_line; } my $content = decode $res->encoding, $res->content; my $tree = HTML::TreeBuilder::XPath->new_from_content($content); my $xpath = selector_to_xpath(&quot;strong#ctu&quot;); my $node = $tree->findnodes($xpath)->shift; print $node->as_text;

43. Exmaple (before) <td>Current <strong>UTC</strong> (or GMT/Zulu)-time used: <strong id=&quot;ctu&quot;>Monday, August 27, 2007 at 12:49:46</strong> <br /> > perl -MLWP::Simple -le '$c = get(&quot;http://timeanddate.com/worldclock/&quot;); $c =~ m@<strong id=&quot;ctu&quot;>(.*?)</strong>@ and print $1' Monday, August 27, 2007 at 12:49:46

44. Example (after) #!/usr/bin/perl use strict; use warnings; use Encode; use LWP::UserAgent; use HTTP::Response::Encoding; use HTML::TreeBuilder::XPath; use HTML::Selector::XPath qw(selector_to_xpath); my $ua = LWP::UserAgent->new; my $res = $ua->get(&quot;http://www.timeanddate.com/worldclock/&quot;); if ($res->is_error) { die &quot;HTTP GET error: &quot;, $res->status_line; } my $content = decode $res->encoding, $res->content; my $tree = HTML::TreeBuilder::XPath->new_from_content($content); my $xpath = selector_to_xpath(&quot;strong#ctu&quot;); my $node = $tree->findnodes($xpath)->shift; print $node->as_text;

48. Example (before) #!/usr/bin/perl use strict; use warnings; use Encode; use LWP::UserAgent; use HTTP::Response::Encoding; use HTML::TreeBuilder::XPath; use HTML::Selector::XPath qw(selector_to_xpath); my $ua = LWP::UserAgent->new; my $res = $ua->get(&quot;http://www.timeanddate.com/worldclock/&quot;); if ($res->is_error) { die &quot;HTTP GET error: &quot;, $res->status_line; } my $content = decode $res->encoding, $res->content; my $tree = HTML::TreeBuilder::XPath->new_from_content($content); my $xpath = selector_to_xpath(&quot;strong#ctu&quot;); my $node = $tree->findnodes($xpath)->shift; print $node->as_text;

55. <ul class=&quot;sites&quot;> <li><a href=&quot;http://vienna.openguides.org/&quot;>OpenGuides</a></li> <li><a href=&quot;http://vienna.yapceurope.org/&quot;>YAPC::Europe</a></li> </ul>

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