1HTTP::Headers::Util(3)User Contributed Perl DocumentationHTTP::Headers::Util(3)
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NAME

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

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

13       This module provides a few functions that helps parsing and
14       construction of valid HTTP header values.  None of the functions are
15       exported by default.
16
17       The following functions are available:
18
19       split_header_words( @header_values )
20           This function will parse the header values given as argument into a
21           list of anonymous arrays containing key/value pairs.  The function
22           knows how to deal with ",", ";" and "=" as well as quoted values
23           after "=".  A list of space separated tokens are parsed as if they
24           were separated by ";".
25
26           If the @header_values passed as argument contains multiple values,
27           then they are treated as if they were a single value separated by
28           comma ",".
29
30           This means that this function is useful for parsing header fields
31           that follow this syntax (BNF as from the HTTP/1.1 specification,
32           but we relax the requirement for tokens).
33
34             headers           = #header
35             header            = (token | parameter) *( [";"] (token | parameter))
36
37             token             = 1*<any CHAR except CTLs or separators>
38             separators        = "(" | ")" | "<" | ">" | "@"
39                               | "," | ";" | ":" | "\" | <">
40                               | "/" | "[" | "]" | "?" | "="
41                               | "{" | "}" | SP | HT
42
43             quoted-string     = ( <"> *(qdtext | quoted-pair ) <"> )
44             qdtext            = <any TEXT except <">>
45             quoted-pair       = "\" CHAR
46
47             parameter         = attribute "=" value
48             attribute         = token
49             value             = token | quoted-string
50
51           Each header is represented by an anonymous array of key/value
52           pairs.  The keys will be all be forced to lower case.  The value
53           for a simple token (not part of a parameter) is "undef".
54           Syntactically incorrect headers will not necessary be parsed as you
55           would want.
56
57           This is easier to describe with some examples:
58
59              split_header_words('foo="bar"; port="80,81"; DISCARD, BAR=baz');
60              split_header_words('text/html; charset="iso-8859-1"');
61              split_header_words('Basic realm="\\"foo\\\\bar\\""');
62
63           will return
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65              [foo=>'bar', port=>'80,81', discard=> undef], [bar=>'baz' ]
66              ['text/html' => undef, charset => 'iso-8859-1']
67              [basic => undef, realm => "\"foo\\bar\""]
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69           If you don't want the function to convert tokens and attribute keys
70           to lower case you can call it as "_split_header_words" instead
71           (with a leading underscore).
72
73       join_header_words( @arrays )
74           This will do the opposite of the conversion done by
75           split_header_words().  It takes a list of anonymous arrays as
76           arguments (or a list of key/value pairs) and produces a single
77           header value.  Attribute values are quoted if needed.
78
79           Example:
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81              join_header_words(["text/plain" => undef, charset => "iso-8859/1"]);
82              join_header_words("text/plain" => undef, charset => "iso-8859/1");
83
84           will both return the string:
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86              text/plain; charset="iso-8859/1"
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89       Copyright 1997-1998, Gisle Aas
90
91       This library is free software; you can redistribute it and/or modify it
92       under the same terms as Perl itself.
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96perl v5.12.4                      2009-06-13            HTTP::Headers::Util(3)
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