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lib::HTML::LinkExtor

Section: User Contributed Perl Documentation (3)
Updated: perl 5.004, patch 04
Index

NAME

HTML::LinkExtor - Extract links from an HTML document

SYNOPSIS

 require HTML::LinkExtor; $p = HTML::LinkExtor->new(\&cb, "http://www.sn.no/"); sub cb {     my($tag, %links) = @_;     print "$tag @{[%links]}\n"; } $p->parse_file("index.html");

DESCRIPTION

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

$p = HTML::LinkExtor->new([$callback[, $base]])

The constructor takes two optional argument. The first is a referenceto a callback routine. It will be called as links are found. If acallback is not provided, then links are just accumulated internallyand can be retrieved by calling the $p->links() method.

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

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

$p->links

Returns a list of all links found in the document. The returnedvalues will be anonymous arrays with the follwing elements:

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

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

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

EXAMPLE

This is an example showing how you can extract links from a documentreceived using LWP:

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

  $url = "http://www.sn.no/";  # for instance  $ua = new LWP::UserAgent;

  # 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 diffent 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";

COPYRIGHT

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

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