HTML::LinkExtor - Extract links from an HTML document
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");
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.
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 $base. The callback is called with the
lowercase tag name as first argument, and then all link attributes as
separate key/value pairs. All non-link attributes are removed.
Returns a list of all links found in the document. The returned
values will be anonymous arrays with the following elements: [$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.
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 dont 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";
HTML::Parser, HTML::Tagset, LWP, URI::URL
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.