HTML::LinkExtor(3)					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]}
";
	}
	$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.

       $p = HTML::LinkExtor->new([$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 follwing 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 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("
", @imgs), "
";

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.

perl v5.8.0							    2001-04-10							HTML::LinkExtor(3)