DOKK / manpages / debian 12 / libhtml-parser-perl / HTML::HeadParser.3pm.en
HTML::HeadParser(3pm) User Contributed Perl Documentation HTML::HeadParser(3pm)

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

 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="...">

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:

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

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)".

 $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"

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 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.

2023-02-04 perl v5.36.0