Detect Browser Language in PHP

Question

Hi, I have this script as INDEX for my website. Script should be include on itself a specific page depending on browser language (automatically detected). This script was working till now, and now suddenly seems not working any more (I do not why), the problem is for any detected language it is always include index_en.php.

Could you please give have a look and let me know what could be wrong? thanks for your time

   <?php
// Open session var
session_start();
// views: 1 = first visit; >1 = second visit

// Detect language from user agent browser
function lixlpixel_get_env_var($Var)
{
     if(empty($GLOBALS[$Var]))
     {
         $GLOBALS[$Var]=(!empty($GLOBALS['_SERVER'][$Var]))?
         $GLOBALS['_SERVER'][$Var] : (!empty($GLOBALS['HTTP_SERVER_VARS'][$Var])) ? $GLOBALS['HTTP_SERVER_VARS'][$Var]:'';
     }
}

function lixlpixel_detect_lang()
{
     // Detect HTTP_ACCEPT_LANGUAGE & HTTP_USER_AGENT.
     lixlpixel_get_env_var('HTTP_ACCEPT_LANGUAGE');
     lixlpixel_get_env_var('HTTP_USER_AGENT');

     $_AL=strtolower($GLOBALS['HTTP_ACCEPT_LANGUAGE']);
     $_UA=strtolower($GLOBALS['HTTP_USER_AGENT']);

     // Try to detect Primary language if several languages are accepted.
     foreach($GLOBALS['_LANG'] as $K)
     {
         if(strpos($_AL, $K)===0)
         return $K;
     }

     // Try to detect any language if not yet detected.
     foreach($GLOBALS['_LANG'] as $K)
     {
         if(strpos($_AL, $K)!==false)
         return $K;
     }
     foreach($GLOBALS['_LANG'] as $K)
     {
         //if(preg_match("/[[( ]{$K}[;,_-)]/",$_UA)) // matching other letters (create an error for seo spyder)
         return $K;
     }

     // Return default language if language is not yet detected.
     return $GLOBALS['_DLANG'];
}

// Define default language.
$GLOBALS['_DLANG']='en';

// Define all available languages.
// WARNING: uncomment all available languages

$GLOBALS['_LANG'] = array(
'af', // afrikaans.
'ar', // arabic.
'bg', // bulgarian.
'ca', // catalan.
'cs', // czech.
'da', // danish.
'de', // german.
'el', // greek.
'en', // english.
'es', // spanish.
'et', // estonian.
'fi', // finnish.
'fr', // french.
'gl', // galician.
'he', // hebrew.
'hi', // hindi.
'hr', // croatian.
'hu', // hungarian.
'id', // indonesian.
'it', // italian.
'ja', // japanese.
'ko', // korean.
'ka', // georgian.
'lt', // lithuanian.
'lv', // latvian.
'ms', // malay.
'nl', // dutch.
'no', // norwegian.
'pl', // polish.
'pt', // portuguese.
'ro', // romanian.
'ru', // russian.
'sk', // slovak.
'sl', // slovenian.
'sq', // albanian.
'sr', // serbian.
'sv', // swedish.
'th', // thai.
'tr', // turkish.
'uk', // ukrainian.
'zh' // chinese.
);

// Redirect to the correct location.
// Example Implementation aff var lang to name file
/*
echo 'The Language detected is: '.lixlpixel_detect_lang(); // For Demonstration
echo "<br />";    
*/
$lang_var = lixlpixel_detect_lang(); //insert lang var system in a new var for conditional statement
/*
echo "<br />";    

echo $lang_var; // print var for trace

echo "<br />";    
*/
// Insert the right page iacoording with the language in the browser
switch ($lang_var){
    case "fr":
        //echo "PAGE DE";
        include("index_fr.php");//include check session DE
        break;
    case "it":
        //echo "PAGE IT";
        include("index_it.php");
        break;
    case "en":
        //echo "PAGE EN";
        include("index_en.php");
        break;        
    default:
        //echo "PAGE EN - Setting Default";
        include("index_en.php");//include EN in all other cases of different lang detection
        break;
}
?>

Answer 1

why dont you keep it simple and clean

<?
$lang = substr($_SERVER['HTTP_ACCEPT_LANGUAGE'], 0, 2);
switch ($lang){
    case "fr":
        //echo "PAGE DE";
        include("index_fr.php");//include check session DE
        break;
    case "it":
        //echo "PAGE IT";
        include("index_it.php");
        break;
    case "en":
        //echo "PAGE EN";
        include("index_en.php");
        break;        
    default:
        //echo "PAGE EN - Setting Default";
        include("index_en.php");//include EN in all other cases of different lang detection
        break;
}
?>

Answer 2

Accept-Language is a list of weighted values (see q parameter). That means just looking at the first language does not mean it’s also the most preferred; in fact, a q value of 0 means not acceptable at all.

So instead of just looking at the first language, parse the list of accepted languages and available languages and find the best match:

// parse list of comma separated language tags and sort it by the quality value
function parseLanguageList($languageList) {
    if (is_null($languageList)) {
        if (!isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
            return array();
        }
        $languageList = $_SERVER['HTTP_ACCEPT_LANGUAGE'];
    }
    $languages = array();
    $languageRanges = explode(',', trim($languageList));
    foreach ($languageRanges as $languageRange) {
        if (preg_match('/(\*|[a-zA-Z0-9]{1,8}(?:-[a-zA-Z0-9]{1,8})*)(?:\s*;\s*q\s*=\s*(0(?:\.\d{0,3})|1(?:\.0{0,3})))?/', trim($languageRange), $match)) {
            if (!isset($match[2])) {
                $match[2] = '1.0';
            } else {
                $match[2] = (string) floatval($match[2]);
            }
            if (!isset($languages[$match[2]])) {
                $languages[$match[2]] = array();
            }
            $languages[$match[2]][] = strtolower($match[1]);
        }
    }
    krsort($languages);
    return $languages;
}

// compare two parsed arrays of language tags and find the matches
function findMatches($accepted, $available) {
    $matches = array();
    $any = false;
    foreach ($accepted as $acceptedQuality => $acceptedValues) {
        $acceptedQuality = floatval($acceptedQuality);
        if ($acceptedQuality === 0.0) continue;
        foreach ($available as $availableQuality => $availableValues) {
            $availableQuality = floatval($availableQuality);
            if ($availableQuality === 0.0) continue;
            foreach ($acceptedValues as $acceptedValue) {
                if ($acceptedValue === '*') {
                    $any = true;
                }
                foreach ($availableValues as $availableValue) {
                    $matchingGrade = matchLanguage($acceptedValue, $availableValue);
                    if ($matchingGrade > 0) {
                        $q = (string) ($acceptedQuality * $availableQuality * $matchingGrade);
                        if (!isset($matches[$q])) {
                            $matches[$q] = array();
                        }
                        if (!in_array($availableValue, $matches[$q])) {
                            $matches[$q][] = $availableValue;
                        }
                    }
                }
            }
        }
    }
    if (count($matches) === 0 && $any) {
        $matches = $available;
    }
    krsort($matches);
    return $matches;
}

// compare two language tags and distinguish the degree of matching
function matchLanguage($a, $b) {
    $a = explode('-', $a);
    $b = explode('-', $b);
    for ($i=0, $n=min(count($a), count($b)); $i<$n; $i++) {
        if ($a[$i] !== $b[$i]) break;
    }
    return $i === 0 ? 0 : (float) $i / count($a);
}

$accepted = parseLanguageList($_SERVER['HTTP_ACCEPT_LANGUAGE']);
var_dump($accepted);
$available = parseLanguageList('en, fr, it');
var_dump($available);
$matches = findMatches($accepted, $available);
var_dump($matches);

If findMatches returns an empty array, no match was found and you can fall back on the default language.