Google​/PHP4Translate

<?php
$api = '....';
$ggl = 'https://www.googleapis.com/language/translate/v2';

$txt = '';
$src = '';
$dst = '';

if (isset($_GET['text'])) $txt = htmlentities($_GET['text'], ENT_QUOTES, 'utf-8');
if (isset($_GET['fr']))   $src = $_GET['fr'];
if (isset($_GET['to']))   $dst = $_GET['to'];
$osrc = $src;

//
if ($src==='auto' || empty($src)) {
       if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
               $langs = explode(',', $_SERVER['HTTP_ACCEPT_LANGUAGE']);
               $langs = array_reverse($langs);
               foreach($langs as $lang) {
                       $ctr = substr($lang, 0, 2);
                       if ($ctr!=$dst) {
                               $src = $ctr;
                               break;
                       }
               }
       }
       if ($src==='auto' || empty($src)) {
               if      ($dst!=='ja') $src = 'ja';
               else if ($dst!=='en') $src = 'en';
       }
}

//
if (!empty($txt) && !empty($src) && !empty($dst) && strlen($src)==2 && strlen($dst)==2 && $src!=$dst) {
       //
       $url = $ggl.'?key='.$api.'&q='.rawurlencode($txt).'&source='.$src.'&target='.$dst;

       $hndl = curl_init($url);
       curl_setopt($hndl, CURLOPT_RETURNTRANSFER, true);
       $resp = curl_exec($hndl);                         
       curl_close($hndl);

       $decd = json_decode($resp, true);

       if (array_key_exists('data', $decd)) {
               echo $decd['data']['translations'][0]['translatedText'];
       }
       else {
               echo 'ERROR : Google Translate returns error!!';
               error_log('trans.php: osrc = '.$osrc.', src = '.$src.', dist = '.$dst.', text = '.$txt);
               error_log('trans.php: '.print_r($decd, true));
       }
}
else {
       error_log('trans.php: osrc = '.$osrc.', src = '.$src.', dist = '.$dst.', text = '.$txt);
}