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1 | package Encode::MIME::Header; |
2 | use strict; |
3 | # use warnings; |
bedba681 |
4 | our $VERSION = do { my @r = (q$Revision: 1.8 $ =~ /\d+/g); sprintf "%d."."%02d" x $#r, @r }; |
5 | use Encode qw(find_encoding encode_utf8 decode_utf8); |
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6 | use MIME::Base64; |
7 | use Carp; |
8 | |
9 | my %seed = |
10 | ( |
11 | decode_b => '1', # decodes 'B' encoding ? |
12 | decode_q => '1', # decodes 'Q' encoding ? |
13 | encode => 'B', # encode with 'B' or 'Q' ? |
14 | bpl => 75, # bytes per line |
15 | ); |
16 | |
17 | $Encode::Encoding{'MIME-Header'} = |
18 | bless { |
19 | %seed, |
20 | Name => 'MIME-Header', |
21 | } => __PACKAGE__; |
22 | |
23 | $Encode::Encoding{'MIME-B'} = |
24 | bless { |
25 | %seed, |
26 | decode_q => 0, |
27 | Name => 'MIME-B', |
28 | } => __PACKAGE__; |
29 | |
30 | $Encode::Encoding{'MIME-Q'} = |
31 | bless { |
32 | %seed, |
33 | decode_q => 1, |
34 | encode => 'Q', |
35 | Name => 'MIME-Q', |
36 | } => __PACKAGE__; |
37 | |
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38 | use base qw(Encode::Encoding); |
39 | |
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40 | sub needs_lines { 1 } |
41 | sub perlio_ok{ 0 }; |
42 | |
43 | sub decode($$;$){ |
44 | use utf8; |
45 | my ($obj, $str, $chk) = @_; |
46 | # zap spaces between encoded words |
47 | $str =~ s/\?=\s+=\?/\?==\?/gos; |
48 | # multi-line header to single line |
49 | $str =~ s/(:?\r|\n|\r\n)[ \t]//gos; |
50 | $str =~ |
51 | s{ |
52 | =\? # begin encoded word |
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53 | ([0-9A-Za-z\-_]+) # charset (encoding) |
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54 | \?([QqBb])\? # delimiter |
55 | (.*?) # Base64-encodede contents |
56 | \?= # end encoded word |
57 | }{ |
58 | if (uc($2) eq 'B'){ |
59 | $obj->{decode_b} or croak qq(MIME "B" unsupported); |
60 | decode_b($1, $3); |
61 | }elsif(uc($2) eq 'Q'){ |
62 | $obj->{decode_q} or croak qq(MIME "Q" unsupported); |
63 | decode_q($1, $3); |
64 | }else{ |
65 | croak qq(MIME "$2" encoding is nonexistent!); |
66 | } |
67 | }egox; |
68 | $_[1] = '' if $chk; |
69 | return $str; |
70 | } |
71 | |
72 | sub decode_b{ |
73 | my $enc = shift; |
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74 | my $d = find_encoding($enc) or croak qq(Unknown encoding "$enc"); |
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75 | my $db64 = decode_base64(shift); |
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76 | return $d->name eq 'utf8' ? |
77 | Encode::decode_utf8($db64) : $d->decode($db64, Encode::FB_PERLQQ); |
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78 | } |
79 | |
80 | sub decode_q{ |
81 | my ($enc, $q) = @_; |
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82 | my $d = find_encoding($enc) or croak qq(Unknown encoding "$enc"); |
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83 | $q =~ s/_/ /go; |
84 | $q =~ s/=([0-9A-Fa-f]{2})/pack("C", hex($1))/ego; |
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85 | return $d->name eq 'utf8' ? |
86 | Encode::decode_utf8($q) : $d->decode($q, Encode::FB_PERLQQ); |
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87 | } |
88 | |
89 | my $especials = |
90 | join('|' => |
91 | map {quotemeta(chr($_))} |
92 | unpack("C*", qq{()<>@,;:\"\'/[]?.=})); |
93 | |
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94 | my $re_encoded_word = |
95 | qr{ |
96 | (?: |
97 | =\? # begin encoded word |
98 | (?:[0-9A-Za-z\-_]+) # charset (encoding) |
99 | \?(?:[QqBb])\? # delimiter |
100 | (?:.*?) # Base64-encodede contents |
101 | \?= # end encoded word |
102 | ) |
103 | }xo; |
104 | |
105 | my $re_especials = qr{$re_encoded_word|$especials}xo; |
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106 | |
107 | sub encode($$;$){ |
108 | my ($obj, $str, $chk) = @_; |
109 | my @line = (); |
110 | for my $line (split /\r|\n|\r\n/o, $str){ |
111 | my (@word, @subline); |
112 | for my $word (split /($re_especials)/o, $line){ |
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113 | if ($word =~ /[^\x00-\x7f]/o or $word =~ /^$re_encoded_word$/o){ |
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114 | push @word, $obj->_encode($word); |
115 | }else{ |
116 | push @word, $word; |
117 | } |
118 | } |
119 | my $subline = ''; |
120 | for my $word (@word){ |
121 | use bytes (); |
122 | if (bytes::length($subline) + bytes::length($word) > $obj->{bpl}){ |
123 | push @subline, $subline; |
124 | $subline = ''; |
125 | } |
126 | $subline .= $word; |
127 | } |
128 | $subline and push @subline, $subline; |
129 | push @line, join("\n " => @subline); |
130 | } |
131 | $_[1] = '' if $chk; |
132 | return join("\n", @line); |
133 | } |
134 | |
135 | use constant HEAD => '=?UTF-8?'; |
136 | use constant TAIL => '?='; |
137 | use constant SINGLE => { B => \&_encode_b, Q => \&_encode_q, }; |
138 | |
139 | sub _encode{ |
140 | my ($o, $str) = @_; |
141 | my $enc = $o->{encode}; |
142 | my $llen = ($o->{bpl} - length(HEAD) - 2 - length(TAIL)); |
11067275 |
143 | # to coerce a floating-point arithmetics, the following contains |
144 | # .0 in numbers -- dankogai |
145 | $llen *= $enc eq 'B' ? 3.0/4.0 : 1.0/3.0; |
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146 | my @result = (); |
147 | my $chunk = ''; |
148 | while(my $chr = substr($str, 0, 1, '')){ |
149 | use bytes (); |
150 | if (bytes::length($chunk) + bytes::length($chr) > $llen){ |
151 | push @result, SINGLE->{$enc}($chunk); |
152 | $chunk = ''; |
153 | } |
154 | $chunk .= $chr; |
155 | } |
156 | $chunk and push @result, SINGLE->{$enc}($chunk); |
157 | return @result; |
158 | } |
159 | |
160 | sub _encode_b{ |
161 | HEAD . 'B?' . encode_base64(encode_utf8(shift), '') . TAIL; |
162 | } |
163 | |
164 | sub _encode_q{ |
165 | my $chunk = shift; |
166 | $chunk =~ s{ |
167 | ([^0-9A-Za-z]) |
168 | }{ |
169 | join("" => map {sprintf "=%02X", $_} unpack("C*", $1)) |
170 | }egox; |
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171 | return decode_utf8(HEAD . 'Q?' . $chunk . TAIL); |
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172 | } |
173 | |
174 | 1; |
175 | __END__ |
176 | |
177 | =head1 NAME |
178 | |
179 | Encode::MIME::Header -- MIME 'B' and 'Q' header encoding |
180 | |
181 | =head1 SYNOPSIS |
182 | |
183 | use Encode qw/encode decode/; |
184 | $utf8 = decode('MIME-Header', $header); |
185 | $header = encode('MIME-Header', $utf8); |
186 | |
187 | =head1 ABSTRACT |
188 | |
189 | This module implements RFC 2047 Mime Header Encoding. There are 3 |
190 | variant encoding names; C<MIME-Header>, C<MIME-B> and C<MIME-Q>. The |
191 | difference is described below |
192 | |
193 | decode() encode() |
194 | ---------------------------------------------- |
195 | MIME-Header Both B and Q =?UTF-8?B?....?= |
196 | MIME-B B only; Q croaks =?UTF-8?B?....?= |
197 | MIME-Q Q only; B croaks =?UTF-8?Q?....?= |
198 | |
199 | =head1 DESCRIPTION |
200 | |
201 | When you decode(=?I<encoding>?I<X>?I<ENCODED WORD>?=), I<ENCODED WORD> |
202 | is extracted and decoded for I<X> encoding (B for Base64, Q for |
203 | Quoted-Printable). Then the decoded chunk is fed to |
204 | decode(I<encoding>). So long as I<encoding> is supported by Encode, |
205 | any source encoding is fine. |
206 | |
207 | When you encode, it just encodes UTF-8 string with I<X> encoding then |
208 | quoted with =?UTF-8?I<X>?....?= . The parts that RFC 2047 forbids to |
209 | encode are left as is and long lines are folded within 76 bytes per |
210 | line. |
211 | |
212 | =head1 BUGS |
213 | |
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214 | It would be nice to support encoding to non-UTF8, such as =?ISO-2022-JP? |
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215 | and =?ISO-8859-1?= but that makes the implementation too complicated. |
216 | These days major mail agents all support =?UTF-8? so I think it is |
217 | just good enough. |
218 | |
219 | =head1 SEE ALSO |
220 | |
221 | L<Encode> |
222 | |
223 | RFC 2047, L<http://www.faqs.org/rfcs/rfc2047.html> and many other |
224 | locations. |
225 | |
226 | =cut |