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+package HTML::HeadParser;
+
+=head1 NAME
+
+HTML::HeadParser - Parse <HEAD> section of a HTML document
+
+=head1 SYNOPSIS
+
+ require HTML::HeadParser;
+ $p = HTML::HeadParser->new;
+ $p->parse($text) and print "not finished";
+
+ $p->header('Title') # to access <title>....</title>
+ $p->header('Content-Base') # to access <base href="http://...">
+ $p->header('Foo') # to access <meta http-equiv="Foo" content="...">
+ $p->header('X-Meta-Author') # to access <meta name="author" content="...">
+ $p->header('X-Meta-Charset') # to access <meta charset="...">
+
+=head1 DESCRIPTION
+
+The C<HTML::HeadParser> is a specialized (and lightweight)
+C<HTML::Parser> that will only parse the E<lt>HEAD>...E<lt>/HEAD>
+section of an HTML document. The parse() method
+will return a FALSE value as soon as some E<lt>BODY> element or body
+text are found, and should not be called again after this.
+
+Note that the C<HTML::HeadParser> might get confused if raw undecoded
+UTF-8 is passed to the parse() method. Make sure the strings are
+properly decoded before passing them on.
+
+The C<HTML::HeadParser> keeps a reference to a header object, and the
+parser will update this header object as the various elements of the
+E<lt>HEAD> section of the HTML document are recognized. The following
+header fields are affected:
+
+=over 4
+
+=item Content-Base:
+
+The I<Content-Base> header is initialized from the E<lt>base
+href="..."> element.
+
+=item Title:
+
+The I<Title> header is initialized from the E<lt>title>...E<lt>/title>
+element.
+
+=item Isindex:
+
+The I<Isindex> header will be added if there is a E<lt>isindex>
+element in the E<lt>head>. The header value is initialized from the
+I<prompt> attribute if it is present. If no I<prompt> attribute is
+given it will have '?' as the value.
+
+=item X-Meta-Foo:
+
+All E<lt>meta> elements containing a C<name> attribute will result in
+headers using the prefix C<X-Meta-> appended with the value of the
+C<name> attribute as the name of the header, and the value of the
+C<content> attribute as the pushed header value.
+
+E<lt>meta> elements containing a C<http-equiv> attribute will result
+in headers as in above, but without the C<X-Meta-> prefix in the
+header name.
+
+E<lt>meta> elements containing a C<charset> attribute will result in
+an C<X-Meta-Charset> header, using the value of the C<charset>
+attribute as the pushed header value.
+
+The ':' character can't be represented in header field names, so
+if the meta element contains this char it's substituted with '-'
+before forming the field name.
+
+=back
+
+=head1 METHODS
+
+The following methods (in addition to those provided by the
+superclass) are available:
+
+=over 4
+
+=cut
+
+
+require HTML::Parser;
+@ISA = qw(HTML::Parser);
+
+use HTML::Entities ();
+
+use strict;
+use vars qw($VERSION $DEBUG);
+#$DEBUG = 1;
+$VERSION = "3.71";
+
+=item $hp = HTML::HeadParser->new
+
+=item $hp = HTML::HeadParser->new( $header )
+
+The object constructor. The optional $header argument should be a
+reference to an object that implement the header() and push_header()
+methods as defined by the C<HTTP::Headers> class. Normally it will be
+of some class that is a or delegates to the C<HTTP::Headers> class.
+
+If no $header is given C<HTML::HeadParser> will create an
+C<HTTP::Headers> object by itself (initially empty).
+
+=cut
+
+sub new
+{
+ my($class, $header) = @_;
+ unless ($header) {
+ require HTTP::Headers;
+ $header = HTTP::Headers->new;
+ }
+
+ my $self = $class->SUPER::new(api_version => 3,
+ start_h => ["start", "self,tagname,attr"],
+ end_h => ["end", "self,tagname"],
+ text_h => ["text", "self,text"],
+ ignore_elements => [qw(script style)],
+ );
+ $self->{'header'} = $header;
+ $self->{'tag'} = ''; # name of active element that takes textual content
+ $self->{'text'} = ''; # the accumulated text associated with the element
+ $self;
+}
+
+=item $hp->header;
+
+Returns a reference to the header object.
+
+=item $hp->header( $key )
+
+Returns a header value. It is just a shorter way to write
+C<$hp-E<gt>header-E<gt>header($key)>.
+
+=cut
+
+sub header
+{
+ my $self = shift;
+ return $self->{'header'} unless @_;
+ $self->{'header'}->header(@_);
+}
+
+sub as_string # legacy
+{
+ my $self = shift;
+ $self->{'header'}->as_string;
+}
+
+sub flush_text # internal
+{
+ my $self = shift;
+ my $tag = $self->{'tag'};
+ my $text = $self->{'text'};
+ $text =~ s/^\s+//;
+ $text =~ s/\s+$//;
+ $text =~ s/\s+/ /g;
+ print "FLUSH $tag => '$text'\n" if $DEBUG;
+ if ($tag eq 'title') {
+ my $decoded;
+ $decoded = utf8::decode($text) if $self->utf8_mode && defined &utf8::decode;
+ HTML::Entities::decode($text);
+ utf8::encode($text) if $decoded;
+ $self->{'header'}->push_header(Title => $text);
+ }
+ $self->{'tag'} = $self->{'text'} = '';
+}
+
+# This is an quote from the HTML3.2 DTD which shows which elements
+# that might be present in a <HEAD>...</HEAD>. Also note that the
+# <HEAD> tags themselves might be missing:
+#
+# <!ENTITY % head.content "TITLE & ISINDEX? & BASE? & STYLE? &
+# SCRIPT* & META* & LINK*">
+#
+# <!ELEMENT HEAD O O (%head.content)>
+#
+# From HTML 4.01:
+#
+# <!ENTITY % head.misc "SCRIPT|STYLE|META|LINK|OBJECT">
+# <!ENTITY % head.content "TITLE & BASE?">
+# <!ELEMENT HEAD O O (%head.content;) +(%head.misc;)>
+#
+# From HTML 5 as of WD-html5-20090825:
+#
+# One or more elements of metadata content, [...]
+# => base, command, link, meta, noscript, script, style, title
+
+sub start
+{
+ my($self, $tag, $attr) = @_; # $attr is reference to a HASH
+ print "START[$tag]\n" if $DEBUG;
+ $self->flush_text if $self->{'tag'};
+ if ($tag eq 'meta') {
+ my $key = $attr->{'http-equiv'};
+ if (!defined($key) || !length($key)) {
+ if ($attr->{name}) {
+ $key = "X-Meta-\u$attr->{name}";
+ } elsif ($attr->{charset}) { # HTML 5 <meta charset="...">
+ $key = "X-Meta-Charset";
+ $self->{header}->push_header($key => $attr->{charset});
+ return;
+ } else {
+ return;
+ }
+ }
+ $key =~ s/:/-/g;
+ $self->{'header'}->push_header($key => $attr->{content});
+ } elsif ($tag eq 'base') {
+ return unless exists $attr->{href};
+ (my $base = $attr->{href}) =~ s/^\s+//; $base =~ s/\s+$//; # HTML5
+ $self->{'header'}->push_header('Content-Base' => $base);
+ } elsif ($tag eq 'isindex') {
+ # This is a non-standard header. Perhaps we should just ignore
+ # this element
+ $self->{'header'}->push_header(Isindex => $attr->{prompt} || '?');
+ } elsif ($tag =~ /^(?:title|noscript|object|command)$/) {
+ # Just remember tag. Initialize header when we see the end tag.
+ $self->{'tag'} = $tag;
+ } elsif ($tag eq 'link') {
+ return unless exists $attr->{href};
+ # <link href="http:..." rel="xxx" rev="xxx" title="xxx">
+ my $href = delete($attr->{href});
+ $href =~ s/^\s+//; $href =~ s/\s+$//; # HTML5
+ my $h_val = "<$href>";
+ for (sort keys %{$attr}) {
+ next if $_ eq "/"; # XHTML junk
+ $h_val .= qq(; $_="$attr->{$_}");
+ }
+ $self->{'header'}->push_header(Link => $h_val);
+ } elsif ($tag eq 'head' || $tag eq 'html') {
+ # ignore
+ } else {
+ # stop parsing
+ $self->eof;
+ }
+}
+
+sub end
+{
+ my($self, $tag) = @_;
+ print "END[$tag]\n" if $DEBUG;
+ $self->flush_text if $self->{'tag'};
+ $self->eof if $tag eq 'head';
+}
+
+sub text
+{
+ my($self, $text) = @_;
+ print "TEXT[$text]\n" if $DEBUG;
+ unless ($self->{first_chunk}) {
+ # drop Unicode BOM if found
+ if ($self->utf8_mode) {
+ $text =~ s/^\xEF\xBB\xBF//;
+ }
+ else {
+ $text =~ s/^\x{FEFF}//;
+ }
+ $self->{first_chunk}++;
+ }
+ my $tag = $self->{tag};
+ if (!$tag && $text =~ /\S/) {
+ # Normal text means start of body
+ $self->eof;
+ return;
+ }
+ return if $tag ne 'title';
+ $self->{'text'} .= $text;
+}
+
+BEGIN {
+ *utf8_mode = sub { 1 } unless HTML::Entities::UNICODE_SUPPORT;
+}
+
+1;
+
+__END__
+
+=back
+
+=head1 EXAMPLE
+
+ $h = HTTP::Headers->new;
+ $p = HTML::HeadParser->new($h);
+ $p->parse(<<EOT);
+ <title>Stupid example</title>
+ <base href="http://www.linpro.no/lwp/">
+ Normal text starts here.
+ EOT
+ undef $p;
+ print $h->title; # should print "Stupid example"
+
+=head1 SEE ALSO
+
+L<HTML::Parser>, L<HTTP::Headers>
+
+The C<HTTP::Headers> class is distributed as part of the
+I<libwww-perl> package. If you don't have that distribution installed
+you need to provide the $header argument to the C<HTML::HeadParser>
+constructor with your own object that implements the documented
+protocol.
+
+=head1 COPYRIGHT
+
+Copyright 1996-2001 Gisle Aas. All rights reserved.
+
+This library is free software; you can redistribute it and/or
+modify it under the same terms as Perl itself.
+
+=cut
+
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