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1 | |
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2 | # Time-stamp: "2004-06-20 21:47:55 ADT" |
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3 | |
4 | require 5; |
5 | package I18N::LangTags::Detect; |
6 | use strict; |
7 | |
8 | use vars qw( @ISA $VERSION $MATCH_SUPERS $USING_LANGUAGE_TAGS |
9 | $USE_LITERALS $MATCH_SUPERS_TIGHTLY); |
10 | |
11 | BEGIN { unless(defined &DEBUG) { *DEBUG = sub () {0} } } |
12 | # define the constant 'DEBUG' at compile-time |
13 | |
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14 | $VERSION = "1.03"; |
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15 | @ISA = (); |
16 | use I18N::LangTags qw(alternate_language_tags locale2language_tag); |
17 | |
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18 | sub _uniq { my %seen; return grep(!($seen{$_}++), @_); } |
19 | sub _normalize { |
20 | my(@languages) = |
21 | map lc($_), |
22 | grep $_, |
23 | map {; $_, alternate_language_tags($_) } @_; |
24 | return _uniq(@languages) if wantarray; |
25 | return $languages[0]; |
26 | } |
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27 | |
28 | #--------------------------------------------------------------------------- |
29 | # The extent of our functional interface: |
30 | |
31 | sub detect () { return __PACKAGE__->ambient_langprefs; } |
32 | |
33 | #=========================================================================== |
34 | |
35 | sub ambient_langprefs { # always returns things untainted |
36 | my $base_class = $_[0]; |
37 | |
38 | return $base_class->http_accept_langs |
39 | if length( $ENV{'REQUEST_METHOD'} || '' ); # I'm a CGI |
40 | # it's off in its own routine because it's complicated |
41 | |
42 | # Not running as a CGI: try to puzzle out from the environment |
43 | my @languages; |
44 | |
45 | foreach my $envname (qw( LANGUAGE LC_ALL LC_MESSAGES LANG )) { |
46 | next unless $ENV{$envname}; |
47 | DEBUG and print "Noting \$$envname: $ENV{$envname}\n"; |
48 | push @languages, |
49 | map locale2language_tag($_), |
50 | # if it's a lg tag, fine, pass thru (untainted) |
51 | # if it's a locale ID, try converting to a lg tag (untainted), |
52 | # otherwise nix it. |
53 | |
54 | split m/[,:]/, |
55 | $ENV{$envname} |
56 | ; |
57 | last; # first one wins |
58 | } |
59 | |
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60 | if($ENV{'IGNORE_WIN32_LOCALE'}) { |
61 | # no-op |
62 | } elsif(&_try_use('Win32::Locale')) { |
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63 | # If we have that module installed... |
64 | push @languages, Win32::Locale::get_language() || '' |
65 | if defined &Win32::Locale::get_language; |
66 | } |
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67 | return _normalize @languages; |
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68 | } |
69 | |
70 | #--------------------------------------------------------------------------- |
71 | |
72 | sub http_accept_langs { |
73 | # Deal with HTTP "Accept-Language:" stuff. Hassle. |
74 | # This code is more lenient than RFC 3282, which you must read. |
75 | # Hm. Should I just move this into I18N::LangTags at some point? |
76 | no integer; |
77 | |
78 | my $in = (@_ > 1) ? $_[1] : $ENV{'HTTP_ACCEPT_LANGUAGE'}; |
79 | # (always ends up untainting) |
80 | |
81 | return() unless defined $in and length $in; |
82 | |
83 | $in =~ s/\([^\)]*\)//g; # nix just about any comment |
84 | |
85 | if( $in =~ m/^\s*([a-zA-Z][-a-zA-Z]+)\s*$/s ) { |
86 | # Very common case: just one language tag |
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87 | return _normalize $1; |
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88 | } elsif( $in =~ m/^\s*[a-zA-Z][-a-zA-Z]+(?:\s*,\s*[a-zA-Z][-a-zA-Z]+)*\s*$/s ) { |
89 | # Common case these days: just "foo, bar, baz" |
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90 | return _normalize( $in =~ m/([a-zA-Z][-a-zA-Z]+)/g ); |
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91 | } |
92 | |
93 | # Else it's complicated... |
94 | |
95 | $in =~ s/\s+//g; # Yes, we can just do without the WS! |
96 | my @in = $in =~ m/([^,]+)/g; |
97 | my %pref; |
98 | |
99 | my $q; |
100 | foreach my $tag (@in) { |
101 | next unless $tag =~ |
102 | m/^([a-zA-Z][-a-zA-Z]+) |
103 | (?: |
104 | ;q= |
105 | ( |
106 | \d* # a bit too broad of a RE, but so what. |
107 | (?: |
108 | \.\d+ |
109 | )? |
110 | ) |
111 | )? |
112 | $ |
113 | /sx |
114 | ; |
115 | $q = (defined $2 and length $2) ? $2 : 1; |
116 | #print "$1 with q=$q\n"; |
117 | push @{ $pref{$q} }, lc $1; |
118 | } |
119 | |
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120 | return _normalize( |
121 | # Read off %pref, in descending key order... |
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122 | map @{$pref{$_}}, |
123 | sort {$b <=> $a} |
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124 | keys %pref |
125 | ); |
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126 | } |
127 | |
128 | #=========================================================================== |
129 | |
130 | my %tried = (); |
131 | # memoization of whether we've used this module, or found it unusable. |
132 | |
133 | sub _try_use { # Basically a wrapper around "require Modulename" |
134 | # "Many men have tried..." "They tried and failed?" "They tried and died." |
135 | return $tried{$_[0]} if exists $tried{$_[0]}; # memoization |
136 | |
137 | my $module = $_[0]; # ASSUME sane module name! |
138 | { no strict 'refs'; |
139 | return($tried{$module} = 1) |
140 | if defined(%{$module . "::Lexicon"}) or defined(@{$module . "::ISA"}); |
141 | # weird case: we never use'd it, but there it is! |
142 | } |
143 | |
144 | print " About to use $module ...\n" if DEBUG; |
145 | { |
146 | local $SIG{'__DIE__'}; |
147 | eval "require $module"; # used to be "use $module", but no point in that. |
148 | } |
149 | if($@) { |
150 | print "Error using $module \: $@\n" if DEBUG > 1; |
151 | return $tried{$module} = 0; |
152 | } else { |
153 | print " OK, $module is used\n" if DEBUG; |
154 | return $tried{$module} = 1; |
155 | } |
156 | } |
157 | |
158 | #--------------------------------------------------------------------------- |
159 | 1; |
160 | __END__ |
161 | |
162 | |
163 | =head1 NAME |
164 | |
165 | I18N::LangTags::Detect - detect the user's language preferences |
166 | |
167 | =head1 SYNOPSIS |
168 | |
169 | use I18N::LangTags::Detect; |
170 | my @user_wants = I18N::LangTags::Detect::detect(); |
171 | |
172 | =head1 DESCRIPTION |
173 | |
174 | It is a common problem to want to detect what language(s) the user would |
175 | prefer output in. |
176 | |
177 | =head1 FUNCTIONS |
178 | |
179 | This module defines one public function, |
180 | C<I18N::LangTags::Detect::detect()>. This function is not exported |
181 | (nor is even exportable), and it takes no parameters. |
182 | |
183 | In scalar context, the function returns the most preferred language |
184 | tag (or undef if no preference was seen). |
185 | |
186 | In list context (which is usually what you want), |
187 | the function returns a |
188 | (possibly empty) list of language tags representing (best first) what |
189 | languages the user apparently would accept output in. You will |
190 | probably want to pass the output of this through |
191 | C<I18N::LangTags::implicate_supers_tightly(...)> |
192 | or |
193 | C<I18N::LangTags::implicate_supers(...)>, like so: |
194 | |
195 | my @languages = |
196 | I18N::LangTags::implicate_supers_tightly( |
197 | I18N::LangTags::Detect::detect() |
198 | ); |
199 | |
200 | |
201 | =head1 ENVIRONMENT |
202 | |
203 | This module looks for several environment variables, including |
204 | REQUEST_METHOD, HTTP_ACCEPT_LANGUAGE, |
205 | LANGUAGE, LC_ALL, LC_MESSAGES, and LANG. |
206 | |
207 | It will also use the L<Win32::Locale> module, if it's installed. |
208 | |
209 | |
210 | =head1 SEE ALSO |
211 | |
212 | L<I18N::LangTags>, L<Win32::Locale>, L<Locale::Maketext>. |
213 | |
214 | (This module's core code started out as a routine in Locale::Maketext; |
215 | but I moved it here once I realized it was more generally useful.) |
216 | |
217 | |
218 | =head1 COPYRIGHT |
219 | |
220 | Copyright (c) 1998-2004 Sean M. Burke. All rights reserved. |
221 | |
222 | This library is free software; you can redistribute it and/or |
223 | modify it under the same terms as Perl itself. |
224 | |
225 | The programs and documentation in this dist are distributed in |
226 | the hope that they will be useful, but without any warranty; without |
227 | even the implied warranty of merchantability or fitness for a |
228 | particular purpose. |
229 | |
230 | |
231 | =head1 AUTHOR |
232 | |
233 | Sean M. Burke C<sburke@cpan.org> |
234 | |
235 | =cut |
236 | |
237 | # a tip: Put a bit of chopped up pickled ginger in your salad. It's tasty! |