HTTP::Headers::Util - Header value parsing utility functions
use HTTP::Headers::Util qw(split_header_words);
@values = split_header_words($h->header("Content-Type"));
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:
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\""]
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 1997-1998, Gisle Aas
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.