Manpages - HTTP_Headers_Util.3pm

:Headers::Util - Header value parsing utility functions

version 6.33

use :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:

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. Syntactically incorrect headers will not necessarily 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 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”

Gisle Aas <gisle@activestate.com>

This software is copyright (c) 1994 by Gisle Aas.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.