man pages section 3: Library Interfaces and Headers

HTML::LinkExtor (3)

Name

HTML::LinkExtor - Extract links from an HTML document

Synopsis

require HTML::LinkExtor;
$p = HTML::LinkExtor->new(\&cb, "http://www.perl.org/");
sub cb {
my($tag, %links) = @_;
print "$tag @{[%links]}\n";
}
$p->parse_file("index.html");

Description

User Contributed Perl Documentation                         HTML::LinkExtor(3)



NAME
       HTML::LinkExtor - Extract links from an HTML document

SYNOPSIS
        require HTML::LinkExtor;
        $p = HTML::LinkExtor->new(\&cb, "http://www.perl.org/");
        sub cb {
            my($tag, %links) = @_;
            print "$tag @{[%links]}\n";
        }
        $p->parse_file("index.html");

DESCRIPTION
       HTML::LinkExtor is an HTML parser that extracts links from an HTML
       document.  The HTML::LinkExtor is a subclass of HTML::Parser. This
       means that the document should be given to the parser by calling the
       $p->parse() or $p->parse_file() methods.

       $p = HTML::LinkExtor->new
       $p = HTML::LinkExtor->new( $callback )
       $p = HTML::LinkExtor->new( $callback, $base )
           The constructor takes two optional arguments. The first is a
           reference to a callback routine. It will be called as links are
           found. If a callback is not provided, then links are just
           accumulated internally and can be retrieved by calling the
           $p->links() method.

           The $base argument is an optional base URL used to absolutize all
           URLs found.  You need to have the URI module installed if you
           provide $base.

           The callback is called with the lowercase tag name as first
           argument, and then all link attributes as separate key/value pairs.
           All non-link attributes are removed.

       $p->links
           Returns a list of all links found in the document.  The returned
           values will be anonymous arrays with the following elements:

             [$tag, $attr => $url1, $attr2 => $url2,...]

           The $p->links method will also truncate the internal link list.
           This means that if the method is called twice without any parsing
           between them the second call will return an empty list.

           Also note that $p->links will always be empty if a callback routine
           was provided when the HTML::LinkExtor was created.

EXAMPLE
       This is an example showing how you can extract links from a document
       received using LWP:

         use LWP::UserAgent;
         use HTML::LinkExtor;
         use URI::URL;

         $url = "http://www.perl.org/";  # for instance
         $ua = LWP::UserAgent->new;

         # Set up a callback that collect image links
         my @imgs = ();
         sub callback {
            my($tag, %attr) = @_;
            return if $tag ne 'img';  # we only look closer at <img ...>
            push(@imgs, values %attr);
         }

         # Make the parser.  Unfortunately, we don't know the base yet
         # (it might be different from $url)
         $p = HTML::LinkExtor->new(\&callback);

         # Request document and parse it as it arrives
         $res = $ua->request(HTTP::Request->new(GET => $url),
                             sub {$p->parse($_[0])});

         # Expand all image URLs to absolute ones
         my $base = $res->base;
         @imgs = map { $_ = url($_, $base)->abs; } @imgs;

         # Print them out
         print join("\n", @imgs), "\n";


ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+----------------------------------+
       |ATTRIBUTE TYPE |         ATTRIBUTE VALUE          |
       +---------------+----------------------------------+
       |Availability   | library/perl-5/html-entities-532 |
       +---------------+----------------------------------+
       |Stability      | Volatile                         |
       +---------------+----------------------------------+

SEE ALSO
       HTML::Parser, HTML::Tagset, LWP, URI::URL

COPYRIGHT
       Copyright 1996-2001 Gisle Aas.

       This library is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself.



NOTES
       Source code for open source software components in Oracle Solaris can
       be found at https://www.oracle.com/downloads/opensource/solaris-source-
       code-downloads.html.

       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from
       https://cpan.metacpan.org/authors/id/G/GA/GAAS/HTML-Parser-3.72.tar.gz.

       Further information about this software can be found on the open source
       community website at https://metacpan.org/pod/HTML::Entities.



perl v5.32.0                      2013-10-21                HTML::LinkExtor(3)