<?php
/*
* accept-to-gettext.inc -- convert information in 'Accept-*' headers to
* gettext language identifiers.
* Copyright (c) 2003, Wouter Verhelst <wouter@debian.org>
* Copyright (c) 2012-2018, FusionDirectory
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*
* Usage:
*
* $locale=al2gt(<array of supported languages/charsets in gettext syntax>,
* <MIME type of document>);
* setlocale('LC_ALL', $locale); // or 'LC_MESSAGES', or whatever...
*
* Example:
*
* $langs=array('nl_BE.ISO-8859-15','nl_BE.UTF-8','en_US.UTF-8','en_GB.UTF-8');
* $locale=al2gt($langs, 'text/html');
* setlocale('LC_ALL', $locale);
*
* Note that this will send out header information (to be
* RFC2616-compliant), so it must be called before anything is sent to
* the user.
*
* Assumptions made:
* * Charset encodings are written the same way as the Accept-Charset
* HTTP header specifies them (RFC2616), except that they're parsed
* case-insensitive.
* * Country codes and language codes are the same in both gettext and
* the Accept-Language syntax (except for the case differences, which
* are dealt with easily). If not, some input may be ignored.
* * The provided gettext-strings are fully qualified; i.e., no "en_US";
* always "en_US.ISO-8859-15" or "en_US.UTF-8", or whichever has been
* used. "en.ISO-8859-15" is OK, though.
* * The language is more important than the charset; i.e., if the
* following is given:
*
* Accept-Language: nl-be, nl;q=0.8, en-us;q=0.5, en;q=0.3
* Accept-Charset: ISO-8859-15, utf-8;q=0.5
*
* And the supplied parameter contains (amongst others) nl_BE.UTF-8
* and nl.ISO-8859-15, then nl_BE.UTF-8 will be picked.
*
* $Log: accept-to-gettext.inc,v $
* Revision 1.1.1.1 2003/11/19 19:31:15 wouter
* * moved to new CVS repo after death of the old
* * Fixed code to apply a default to both Accept-Charset and
* Accept-Language if none of those headers are supplied; patch from
* Dominic Chambers <dominic@encasa.com>
*
* Revision 1.2 2003/08/14 10:23:59 wouter
* Removed little error in Content-Type header syntaxis.
*
* Revision 2012/06/07 Côme BERNIGAUD
* Rewrote a lot of things, use functions and PHP features in order to be more efficient and more readable
*/
/*!
* \brief Parse a string like nl-be, nl;q=0.8, en-us;q=0.5, en;q=0.3
* into an array like array('nl-be'=>1,'nl'=>0.8,'en-us'=>0.5,'en'=>0.3)
*/
function parse_scores ($str)
{
$scores = [];
$parts = preg_split('/,/', $str);
foreach ($parts as $part) {
$part = trim(strtolower($part));
if (preg_match("/(.*);q=(.*)/", $part, $matches)) {
$scores[$matches[1]] = $matches[2];
} else {
$scores[$part] = 1;
}
}
return $scores;
}
/*!
* \brief Compute the maximum value in scores array, between keys from testvals array.
* example: max_scores(array('a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5),array('a','d','f')) returns 4
* if no key from testvals is found, returns 0
*/
function max_scores ($scores, $testvals)
{
$values = array_intersect_key($scores, array_flip($testvals));
if (empty($values)) {
return 0;
} else {
return max($values);
}
}
/*!
* \brief Parse a lang in gettext format and returns lang, country and charset.
* example: en_US.utf-8 will return ('en','us','utf-8')
*/
function parse_gettext_lang ($str)
{
if (preg_match("/^([^_]*)(_([^_]*))?\.(.*)$/", $str, $m)) {
return [strtolower($m[1]), strtolower($m[3]), strtolower($m[4])];
} else {
return FALSE;
}
}
function al2gt ($gettextlangs)
{
/* Check if ACCEPT_LANGUAGE isset */
if (empty($_SERVER["HTTP_ACCEPT_LANGUAGE"])) {
/* default to "everything is acceptable", as RFC2616 specifies */
$acceptLang = '*';
} else {
$acceptLang = $_SERVER["HTTP_ACCEPT_LANGUAGE"];
}
if (empty($_SERVER["HTTP_ACCEPT_CHARSET"])) {
/* default to "everything is acceptable", as RFC2616 specifies */
$acceptChar = 'ISO-8859-1,*;q=0.5';
} else {
$acceptChar = $_SERVER["HTTP_ACCEPT_CHARSET"];
}
$lang_scores = parse_scores($acceptLang);
$char_scores = parse_scores($acceptChar);
/* RFC2616: ``If no "*" is present in an Accept-Charset field, then
* all character sets not explicitly mentioned get a quality value of
* 0, except for ISO-8859-1, which gets a quality value of 1 if not
* explicitly mentioned.'' */
if (!isset($char_scores['ISO-8859-1']) && !isset($char_scores['*'])) {
$char_scores['ISO-8859-1'] = 1;
}
/* Loop through the available languages/encodings, and pick the one
* with the highest score, excluding the ones with a charset the user
* did not include. */
// The lang with the maximum score found
$max_lang = NULL;
// The lang score of this lang
$max_l_score = 0;
// The char score of this lang
$max_c_score = 0;
foreach ($gettextlangs as $gtlang) {
if (!($infos = parse_gettext_lang($gtlang))) {
continue;
}
list ($lang, $country, $char) = $infos;
$lang_score = max_scores($lang_scores, [$lang,$lang.'-'.$country,'*']);
$char_score = max_scores($char_scores, [$char,'*']);
if ($char_score == 0) {
// exclude charsets the user refuses
continue;
}
// if lang scores are equals we compare char scores
if (($lang_score > $max_l_score)
|| (($lang_score == $max_l_score) && ($char_score > $max_c_score))) {
$max_l_score = $lang_score;
$max_c_score = $char_score;
$max_lang = $gtlang;
}
}
if ($max_lang === NULL) {
return NULL;
}
return $max_lang;
}