HTTP::Headers::Util(3)					User Contributed Perl Documentation				    HTTP::Headers::Util(3)

NAME

       HTTP::Headers::Util - Header value parsing utility functions

SYNOPSIS

	 use HTTP::Headers::Util qw(split_header_words);
	 @values = split_header_words($h->header("Content-Type"));

DESCRIPTION

       This module provides a few functions that helps parsing and construction of valid HTTP header values.  None of the functions are exported
       by default.

       The following functions are available:

       split_header_words( @header_values )
	   This function will parse the header values given as argument into a list of anonymous arrays containing key/value pairs.  The function
	   knows how to deal with ",", ";" and "=" as well as quoted values after "=".	A list of space separated tokens are parsed as if they
	   were separated by ";".

	   If the @header_values passed as argument contains multiple values, then they are treated as if they were a single value separated by
	   comma ",".

	   This means that this function is useful for parsing header fields that follow this syntax (BNF as from the HTTP/1.1 specification, but
	   we relax the requirement for tokens).

	     headers	       = #header
	     header	       = (token | parameter) *( [";"] (token | parameter))

	     token	       = 1*<any CHAR except CTLs or separators>
	     separators        = "(" | ")" | "<" | ">" | "@"
			       | "," | ";" | ":" | "" | <">
			       | "/" | "[" | "]" | "?" | "="
			       | "{" | "}" | SP | HT

	     quoted-string     = ( <"> *(qdtext | quoted-pair ) <"> )
	     qdtext	       = <any TEXT except <">>
	     quoted-pair       = "" CHAR

	     parameter	       = attribute "=" value
	     attribute	       = token
	     value	       = token | quoted-string

	   Each header is represented by an anonymous array of key/value pairs.  The value for a simple token (not part of a parameter) is
	   "undef".  Syntactically incorrect headers will not necessary be parsed as you would want.

	   This is easier to describe with some examples:

	      split_header_words('foo="bar"; port="80,81"; discard, bar=baz')
	      split_header_words('text/html; charset="iso-8859-1");
	      split_header_words('Basic realm=""foo\bar""');

	   will return

	      [foo=>'bar', port=>'80,81', discard=> undef], [bar=>'baz' ]
	      ['text/html' => undef, charset => 'iso-8859-1']
	      [Basic => undef, realm => '"fooar"']

       join_header_words( @arrays )
	   This will do the opposite of the conversion done by split_header_words().  It takes a list of anonymous arrays as arguments (or a list
	   of key/value pairs) and produces a single header value.  Attribute values are quoted if needed.

	   Example:

	      join_header_words(["text/plain" => undef, charset => "iso-8859/1"]);
	      join_header_words("text/plain" => undef, charset => "iso-8859/1");

	   will both return the string:

	      text/plain; charset="iso-8859/1"

COPYRIGHT

       Copyright 1997-1998, Gisle Aas

       This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

libwww-perl-5.65						    2000-09-16						    HTTP::Headers::Util(3)