common/components/LangRequest.php

<?php
namespace common\components;
use Yii;
use yii\web\Request;
use common\models\Language;
use common\models\Page;
use yii\helpers\Url;
class LangRequest extends Request
{  
    private $_lang_url;
    public function getBaseUrl()
    {   
        return str_replace ((IS_FRONT ? '/frontend/web' : '/backend/web'), '', parent::getBaseUrl()) . (IS_FRONT ? '' : '/admin');
    }
    public function getLangUrl()
    {
        if ($this->_lang_url === null) 
        {
	        $this->_lang_url = $this->getUrl();
	        
	    	$url_list = explode ('/', $this->_lang_url);
	    	$lang_url = isset ($url_list[1]) ? $url_list[1] : null;
	    	Language::setCurrent($lang_url);
            if ($lang_url !== null && $lang_url === Language::getCurrent()->lang_code 
                && strpos($this->_lang_url, Language::getCurrent()->lang_code) === 1)
            {
                $this->_lang_url = substr ($this->_lang_url, strlen (Language::getCurrent()->lang_code) + 1);
            }
        }
        return $this->_lang_url;
    }
    protected function resolvePathInfo()
    {
        $pathInfo = $this->getLangUrl();
        if (($pos = strpos ($pathInfo, '?')) !== false) 
        {
            $pathInfo = substr ($pathInfo, 0, $pos);
        }
        $pathInfo = urldecode ($pathInfo);
        // try to encode in UTF8 if not so
        // http://w3.org/International/questions/qa-forms-utf-8.html
        if (! preg_match ('%^(?:
            [\x09\x0A\x0D\x20-\x7E]              # ASCII
            | [\xC2-\xDF][\x80-\xBF]             # non-overlong 2-byte
            | \xE0[\xA0-\xBF][\x80-\xBF]         # excluding overlongs
            | [\xE1-\xEC\xEE\xEF][\x80-\xBF]{2}  # straight 3-byte
            | \xED[\x80-\x9F][\x80-\xBF]         # excluding surrogates
            | \xF0[\x90-\xBF][\x80-\xBF]{2}      # planes 1-3
            | [\xF1-\xF3][\x80-\xBF]{3}          # planes 4-15
            | \xF4[\x80-\x8F][\x80-\xBF]{2}      # plane 16
            )*$%xs', $pathInfo)
        ) 
        {
            $pathInfo = utf8_encode($pathInfo);
        }
        $scriptUrl = $this->getScriptUrl();
        
        $baseUrl = $this->getBaseUrl();
        if (strpos($pathInfo, $scriptUrl) === 0) 
        {
            $pathInfo = substr($pathInfo, strlen($scriptUrl));
        } 
        else if ($baseUrl === '' || strpos($pathInfo, $baseUrl) === 0) 
        {
            $pathInfo = substr($pathInfo, strlen($baseUrl));
        } 
        elseif (isset ($_SERVER['PHP_SELF']) && strpos ($_SERVER['PHP_SELF'], $scriptUrl) === 0) 
        {
            $pathInfo = substr($_SERVER['PHP_SELF'], strlen($scriptUrl));
        } 
        else 
        {
            throw new InvalidConfigException('Unable to determine the path info of the current request.');
        }
        if ($pathInfo[0] === '/') 
        {
            $pathInfo = substr ($pathInfo, 1);
        }
 
        return (string) $pathInfo;
    }
}