Initial Commit

database/perl/vendor/lib/HTML/LinkExtor.pm

@@ -0,0 +1,185 @@
+package HTML::LinkExtor;
+
+require HTML::Parser;
+our @ISA = qw(HTML::Parser);
+our $VERSION = '3.75';
+
+=head1 NAME
+
+HTML::LinkExtor - Extract links from an HTML document
+
+=head1 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");
+
+=head1 DESCRIPTION
+
+I<HTML::LinkExtor> is an HTML parser that extracts links from an
+HTML document.  The I<HTML::LinkExtor> is a subclass of
+I<HTML::Parser>. This means that the document should be given to the
+parser by calling the $p->parse() or $p->parse_file() methods.
+
+=cut
+
+use strict;
+use HTML::Tagset ();
+
+# legacy (some applications grabs this hash directly)
+use vars qw(%LINK_ELEMENT);
+*LINK_ELEMENT = \%HTML::Tagset::linkElements;
+
+=over 4
+
+=item $p = HTML::LinkExtor->new
+
+=item $p = HTML::LinkExtor->new( $callback )
+
+=item $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 I<URI> module installed if you provide $base.
+
+The callback is called with the lowercase tag name as first argument,
+and then all link attributes as separate key/value pairs.  All
+non-link attributes are removed.
+
+=cut
+
+sub new
+{
+    my($class, $cb, $base) = @_;
+    my $self = $class->SUPER::new(
+                    start_h => ["_start_tag", "self,tagname,attr"],
+		    report_tags => [keys %HTML::Tagset::linkElements],
+	       );
+    $self->{extractlink_cb} = $cb;
+    if ($base) {
+	require URI;
+	$self->{extractlink_base} = URI->new($base);
+    }
+    $self;
+}
+
+sub _start_tag
+{
+    my($self, $tag, $attr) = @_;
+
+    my $base = $self->{extractlink_base};
+    my $links = $HTML::Tagset::linkElements{$tag};
+    $links = [$links] unless ref $links;
+
+    my @links;
+    my $a;
+    for $a (@$links) {
+	next unless exists $attr->{$a};
+	(my $link = $attr->{$a}) =~ s/^\s+//; $link =~ s/\s+$//; # HTML5
+	push(@links, $a, $base ? URI->new($link, $base)->abs($base) : $link);
+    }
+    return unless @links;
+    $self->_found_link($tag, @links);
+}
+
+sub _found_link
+{
+    my $self = shift;
+    my $cb = $self->{extractlink_cb};
+    if ($cb) {
+	&$cb(@_);
+    } else {
+	push(@{$self->{'links'}}, [@_]);
+    }
+}
+
+=item $p->links
+
+Returns a list of all links found in the document.  The returned
+values will be anonymous arrays with the following elements:
+
+  [$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 I<HTML::LinkExtor> was created.
+
+=cut
+
+sub links
+{
+    my $self = shift;
+    exists($self->{'links'}) ? @{delete $self->{'links'}} : ();
+}
+
+# We override the parse_file() method so that we can clear the links
+# before we start a new file.
+sub parse_file
+{
+    my $self = shift;
+    delete $self->{'links'};
+    $self->SUPER::parse_file(@_);
+}
+
+=back
+
+=head1 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";
+
+=head1 SEE ALSO
+
+L<HTML::Parser>, L<HTML::Tagset>, L<LWP>, L<URI::URL>
+
+=head1 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.
+
+=cut
+
+1;