Factors to Consider When Choosing Accounts Payable Services Providers.pptx
Web Scraper Shibuya.pm tech talk #8
1. Practical Web Scraping with Web::Scraper Tatsuhiko Miyagawa [email_address] Six Apart, Ltd. / Shibuya Perl Mongers Shibuya.pm Tech Talks #8
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3. 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
4. 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
24. <span class="message">I ♥ Shibuya</span> > perl –MHTML::Entities –e '$c =~ m@<span class="message">(.*?)</span>@ and print decode_entities ($1)' I ♥ Shibuya
25. <span class="message">Perl が大好き！ </span> > perl –MHTML::Entities –MEncode –e '$c =~ m@<span class="message">(.*?)</span>@ and print decode_entities( decode_utf8 ($1))' Wide character in print at –e line 1. Perl が大好き！
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30. XPath <td>Current <strong>UTC</strong> (or GMT/Zulu)-time used: <strong id="ctu">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="ctu"]') ->shift->as_text; # Monday, August 27, 2007 at 12:49:46
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34. CSS Selectors <td>Current <strong>UTC</strong> (or GMT/Zulu)-time used: <strong id="ctu">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 "strong#ctu"; print $tree->findnodes($xpath)->shift->as_text; # Monday, August 27, 2007 at 12:49:46
35. 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 = $ua->get("http://www.timeanddate.com/worldclock/"); if ($res->is_error) { die "HTTP GET error: ", $res->status_line; } my $content = decode $res->encoding, $res->content; my $tree = HTML::TreeBuilder::XPath->new_from_content($content); my $xpath = selector_to_xpath("strong#ctu"); my $node = $tree->findnodes($xpath)->shift; print $node->as_text;
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37. Exmaple (before) <td>Current <strong>UTC</strong> (or GMT/Zulu)-time used: <strong id="ctu">Monday, August 27, 2007 at 12:49:46</strong> <br /> > perl -MLWP::Simple -le '$c = get("http://timeanddate.com/worldclock/"); $c =~ m@<strong id="ctu">(.*?)</strong>@ and print $1' Monday, August 27, 2007 at 12:49:46
38. 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 = $ua->get("http://www.timeanddate.com/worldclock/"); if ($res->is_error) { die "HTTP GET error: ", $res->status_line; } my $content = decode $res->encoding, $res->content; my $tree = HTML::TreeBuilder::XPath->new_from_content($content); my $xpath = selector_to_xpath("strong#ctu"); my $node = $tree->findnodes($xpath)->shift; print $node->as_text;
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42. 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 = $ua->get("http://www.timeanddate.com/worldclock/"); if ($res->is_error) { die "HTTP GET error: ", $res->status_line; } my $content = decode $res->encoding, $res->content; my $tree = HTML::TreeBuilder::XPath->new_from_content($content); my $xpath = selector_to_xpath("strong#ctu"); my $node = $tree->findnodes($xpath)->shift; print $node->as_text;
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