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

- NAME
- SYNOPSIS
- DESCRIPTION
- COPYRIGHT

# 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 => "\"foo\\bar\""]

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.

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