public function getAssetFileSize(){
         
         // Remote file
         if ($this->isAssetFilePathUrl()) {
            if (
                    // Retrieve headers
                    ($aHeaders = get_headers($sAssetFilePath = $this->getAssetFilePath(), 1))
                    // Assert return is OK
                    && strstr($aHeaders[0], '200') !== false
                    // Retrieve content length
                    && !empty($aHeaders['Content-Length']) && $iAssetFileSize = $aHeaders['Content-Length']
            ) {
                return $iAssetFileSize;
            }
            $oCurlHandle = curl_init($sAssetFilePath);
            curl_setopt($oCurlHandle, CURLOPT_NOBODY, true);
            curl_setopt($oCurlHandle, CURLOPT_RETURNTRANSFER, true);           
            if (curl_exec($oCurlHandle) === false) {
                return null;
            }
            return curl_getinfo($oCurlHandle, CURLINFO_CONTENT_LENGTH_DOWNLOAD) ? : null;
        }
        
        // Local file
        \Zend\Stdlib\ErrorHandler::start();
        $iAssetFileSize = filesize($this->getAssetFilePath());
        \Zend\Stdlib\ErrorHandler::stop(true);
        return $iAssetFileSize ? : null;
              
    }