HTML::HeadParser

NAME

HTML::HeadParser − Parse <HEAD> section of a HTML document

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="...">

DESCRIPTION

The "HTML::HeadParser" is a specialized (and lightweight) "HTML::Parser" that will only parse the < HEAD >...</HEAD> section of an HTML document. The parse() method will return a FALSE value as soon as some < BODY > element or body text are found, and should not be called again after this.

Note that the "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 "HTML::HeadParser" keeps a reference to a header object, and the parser will update this header object as the various elements of the < HEAD > section of the HTML document are recognized. The following header fields are affected:
Content-Base:

The Content-Base header is initialized from the <base href="..."> element.

Title:

The Title header is initialized from the <title>...</title> element.

Isindex:

The Isindex header will be added if there is a <isindex> element in the <head>. The header value is initialized from the prompt attribute if it is present. If no prompt attribute is given it will have ’?’ as the value.

X−Meta-Foo:

All <meta> elements containing a "name" attribute will result in headers using the prefix "X−Meta−" appended with the value of the "name" attribute as the name of the header, and the value of the "content" attribute as the pushed header value.

<meta> elements containing a "http−equiv" attribute will result in headers as in above, but without the "X−Meta−" prefix in the header name.

<meta> elements containing a "charset" attribute will result in an "X−Meta−Charset" header, using the value of the "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.

METHODS

The following methods (in addition to those provided by the superclass) are available:
$hp = HTML::HeadParser−>new
$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 "HTTP::Headers" class. Normally it will be of some class that is a or delegates to the "HTTP::Headers" class.

If no $header is given "HTML::HeadParser" will create an "HTTP::Headers" object by itself (initially empty).

$hp−>header;

Returns a reference to the header object.

$hp−>header( $key )

Returns a header value. It is just a shorter way to write "$hp−>header−>header($key)".

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"

SEE ALSO

HTML::Parser, HTTP::Headers

The "HTTP::Headers" class is distributed as part of the libwww-perl package. If you don’t have that distribution installed you need to provide the $header argument to the "HTML::HeadParser" constructor with your own object that implements the documented protocol.

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.