HTTP::Headers::Util(3)User Contributed Perl DocumentatioHTTP::Headers::Util(3)NAMEHTTP::Headers::Util - Header value parsing utility functions
SYNOPSIS
use HTTP::Headers::Utilqw(split_header_words);
@values = split_header_words($h->header("Content-Type"));
DESCRIPTION
This module provides a few functions that helps parsing and construc‐
tion 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 keys will be all be forced to lower case. The value
for a simple token (not part of a parameter) is "undef". Syntacti‐
cally 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\""]
If you don't want the function to convert tokens and attribute keys
to lower case you can call it as "_split_header_words" instead
(with a leading underscore).
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 argu‐
ments (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.
perl v5.8.8 2008-09-24 HTTP::Headers::Util(3)
