Using the PHP HTTP_ACCEPT_LANGUAGE server variable

Question

I created a PHP script that checks the HTTP_ACCEPT_LANGUAGE and loads the website using the appropriate language from the 1st two characters:

          $http_lang = substr($_SERVER["HTTP_ACCEPT_LANGUAGE"],0,2);
      switch ($http_lang) {
        case 'en':
          $SESSION->conf['language'] = 'english';
          break;
        case 'es':
          $SESSION->conf['language'] = 'spanish';
          break;
        default:
          $SESSION->conf['language'] = $PREFS->conf['languages'][$SESSION->conf['language_id']];
      }

If I change the language to Spanish in Firefox the website loads in Spanish fine. However I have had several reports that people in Colombia see the website in english.

Details: "es-co" LCID = 9226 Spanish(Colombia)

Anyone have any ideas as to why this is happening? I thought this was the best way to check what language users support.

Answer 1

I used the regex from @GabrielAnderson and devised this function which behaves according to RFC 2616 (when no quality value is given to a language, it defaults to 1).

When several languages share the same quality value, the most specific are given priority over the less specific ones. (this behaviour is not part of the RFC which provides no recommendation for this specific case)

function Get_Client_Prefered_Language ($getSortedList = false, $acceptedLanguages = false)
{

    if (empty($acceptedLanguages))
        $acceptedLanguages = $_SERVER["HTTP_ACCEPT_LANGUAGE"];

        // regex inspired from @GabrielAnderson on http://stackoverflow.com/questions/6038236/http-accept-language
    preg_match_all('/([a-z]{1,8}(-[a-z]{1,8})*)\s*(;\s*q\s*=\s*(1|0\.[0-9]+))?/i', $acceptedLanguages, $lang_parse);
    $langs = $lang_parse[1];
    $ranks = $lang_parse[4];


        // (create an associative array 'language' => 'preference')
    $lang2pref = array();
    for($i=0; $i<count($langs); $i++)
        $lang2pref[$langs[$i]] = (float) (!empty($ranks[$i]) ? $ranks[$i] : 1);

        // (comparison function for uksort)
    $cmpLangs = function ($a, $b) use ($lang2pref) {
        if ($lang2pref[$a] > $lang2pref[$b])
            return -1;
        elseif ($lang2pref[$a] < $lang2pref[$b])
            return 1;
        elseif (strlen($a) > strlen($b))
            return -1;
        elseif (strlen($a) < strlen($b))
            return 1;
        else
            return 0;
    };

        // sort the languages by prefered language and by the most specific region
    uksort($lang2pref, $cmpLangs);

    if ($getSortedList)
        return $lang2pref;

        // return the first value's key
    reset($lang2pref);
    return key($lang2pref);
}

Example:

print_r(Get_Client_Prefered_Language(true, 'en,en-US,en-AU;q=0.8,fr;q=0.6,en-GB;q=0.4'));

Outputs:

Array
    (
        [en-US] => 1
        [en] => 1
        [en-AU] => 0.8
        [fr] => 0.6
        [en-GB] => 0.4
    )

As you can notice, 'en-US' appears in first position despite the fact that 'en' was first in the given string.

So you could use this function and just replace your first line of code by:

$http_lang = substr(Get_Client_Prefered_Language(),0,2);

Answer 2

if you want to store languages in array, i do this:

preg_match_all('/([a-z]{1,8}(-[a-z]{1,8})?)\s*(;\s*q\s*=\s*(1|0\.[0-9]+))?/i',  'pt-br,pt;q=0.8,en-us;q=0.5,en,en-uk;q=0.3', $lang_parse);
$langs = $lang_parse[1];
$rank = $lang_parse[4];
for($i=0; $i<count($langs); $i++){
    if ($rank[$i] == NULL) $rank[$i] = $rank[$i+1];
}

this output an array to languages e other with values

preg_match_all('/([a-z]{1,8}(-[a-z]{1,8})?)\s*(;\s*q\s*=\s*(1|0\.[0-9]+))?/i', 'pt-br,pt;q=0.8,en-us;q=0.5,en,en-uk;q=0.3', $lang_parse);
$langs = $lang_parse[1];
$rank = $lang_parse[4];
$lang = array();
for($i=0; $i<count($langs); $i++){
    $lang[$langs[$i]] = ($rank[$i] == NULL) ? $rank[$i+1] : $rank[$i];
}

this output an array like this:

Array
(
    [pt-br] => 0.8
    [pt] => 0.8
    [en-us] => 0.5
    [en] => 0.3
    [en-uk] => 0.3
)

Answer 3

I put my trust in the skilled programmers who work for PHP and think ahead. Here is my version of a label for the Google translator drop down.

function gethttplanguage(){
    $langs = array(     
            'en',// default
            'it',
            'dn',
            'fr',
            'es'         
    );
    $questions = array(
    "en" => "If you wish to see this site in another language click here",
    "it" => "Se vuole vedere questo sito in italiano clicca qui",
    "dn" => "Hvis du ønsker at se denne hjemmeside i danske klik her",
    "fr" => "Si vous voulez visualiser ce site en français, cliquez ici",
    "es" => "Si quieres ver este sitio en español haga clic aquí"
    );
    $result = array();  
    http_negotiate_language($langs, &$result);  
    return $questions[key($result)];
}

Answer 4

I will use full locale code to refer language, because like zh-TW and zh-CN is 2 different language.

function httpAcceptLanguage($httpAcceptLanguage = null)
{
    if ($httpAcceptLanguage == null) {
        $httpAcceptLanguage = $_SERVER['HTTP_ACCEPT_LANGUAGE'];
    }

    $languages = explode(',', $httpAcceptLanguage);
    $result = array();
    foreach ($languages as $language) {
        $lang = explode(';q=', $language);
        // $lang == [language, weight], default weight = 1
        $result[$lang[0]] = isset($lang[1]) ? floatval($lang[1]) : 1;
    }

    arsort($result);
    return $result;
}

// zh-TW,en-US;q=0.7,en;q=0.3
echo $_SERVER['HTTP_ACCEPT_LANGUAGE'];
/*
    Array
    (
        [zh-TW] => 1
        [en-US] => 0.7
        [en] => 0.3
    )
 */
print_r(httpAcceptLanguage());

Answer 5

In the end I went with this solution:

if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
  preg_match_all('/([a-z]{1,8}(-[a-z]{1,8})?)\s*(;\s*q\s*=\s*(1|0\.[0-9]+))?/i', $_SERVER['HTTP_ACCEPT_LANGUAGE'], $lang_parse);
  if (count($lang_parse[1])){
    $langs = array_combine($lang_parse[1], $lang_parse[4]);
    foreach ($langs as $lang => $val){
      if ($val === '') $langs[$lang] = 1;
    }
    arsort($langs, SORT_NUMERIC);
  }
  foreach ($langs as $lang => $val){
    if (strpos($lang,'en')===0){
      $language = 'english';
      break;
    } else if (strpos($lang,'es')===0){
      $language = 'spanish';
    }
  }
}

I would like to thank AJ for the links. Also thanks to all that replied.

Answer 6

A more contemporary method would be to use http_negotiate_language():

 $map = array("en" => "english", "es" => "spanish");
 $conf_language= $map[ http_negotiate_language(array_keys($map)) ];

If you don't have the http extension installed (and not the intl one as well), there is yet another workaround in the comments (user-note #86787 (Nov 2008; by Anonymous)):

<?php 
/* 
  determine which language out of an available set the user prefers most 

  $available_languages        array with language-tag-strings (must be lowercase) that are available 
  $http_accept_language    a HTTP_ACCEPT_LANGUAGE string (read from $_SERVER['HTTP_ACCEPT_LANGUAGE'] if left out) 
*/ 
function prefered_language ($available_languages,$http_accept_language="auto") { 
    // if $http_accept_language was left out, read it from the HTTP-Header 
    if ($http_accept_language == "auto") $http_accept_language = isset($_SERVER['HTTP_ACCEPT_LANGUAGE']) ? $_SERVER['HTTP_ACCEPT_LANGUAGE'] : ''; 

    // standard  for HTTP_ACCEPT_LANGUAGE is defined under 
    // http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4 
    // pattern to find is therefore something like this: 
    //    1#( language-range [ ";" "q" "=" qvalue ] ) 
    // where: 
    //    language-range  = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" ) 
    //    qvalue         = ( "0" [ "." 0*3DIGIT ] ) 
    //            | ( "1" [ "." 0*3("0") ] ) 
    preg_match_all("/([[:alpha:]]{1,8})(-([[:alpha:]|-]{1,8}))?" . 
                   "(\s*;\s*q\s*=\s*(1\.0{0,3}|0\.\d{0,3}))?\s*(,|$)/i", 
                   $http_accept_language, $hits, PREG_SET_ORDER); 

    // default language (in case of no hits) is the first in the array 
    $bestlang = $available_languages[0]; 
    $bestqval = 0; 

    foreach ($hits as $arr) { 
        // read data from the array of this hit 
        $langprefix = strtolower ($arr[1]); 
        if (!empty($arr[3])) { 
            $langrange = strtolower ($arr[3]); 
            $language = $langprefix . "-" . $langrange; 
        } 
        else $language = $langprefix; 
        $qvalue = 1.0; 
        if (!empty($arr[5])) $qvalue = floatval($arr[5]); 

        // find q-maximal language  
        if (in_array($language,$available_languages) && ($qvalue > $bestqval)) { 
            $bestlang = $language; 
            $bestqval = $qvalue; 
        } 
        // if no direct hit, try the prefix only but decrease q-value by 10% (as http_negotiate_language does) 
        else if (in_array($langprefix,$available_languages) && (($qvalue*0.9) > $bestqval)) { 
            $bestlang = $langprefix; 
            $bestqval = $qvalue*0.9; 
        } 
    } 
    return $bestlang; 
} 
?>