private function getIfModifiedSinceTimestamp()
    {
        if (!empty($_SERVER[self::HTTP_IF_MODIFIED_SINCE])) {
            $modifiedSinceString = $_SERVER[self::HTTP_IF_MODIFIED_SINCE];
        } elseif (!empty($_ENV[self::HTTP_IF_MODIFIED_SINCE])) {
            $modifiedSinceString = $_ENV[self::HTTP_IF_MODIFIED_SINCE];
        } else {
            $modifiedSinceString = null;
        }

        if ($modifiedSinceString) {
            // Some versions of IE 6 append "; length=##"
            if (($pos = strpos($modifiedSinceString, ';')) !== false) {
                $modifiedSinceString = substr($modifiedSinceString, 0, $pos);
            }

            return strtotime($modifiedSinceString);
        }

        return false;
    }
private function getIfModifiedSinceTimestamp()
    {
        if (!empty($_SERVER[self::HTTP_IF_MODIFIED_SINCE])) {
            $modifiedSinceString = $_SERVER[self::HTTP_IF_MODIFIED_SINCE];
        } elseif (!empty($_ENV[self::HTTP_IF_MODIFIED_SINCE])) {
            $modifiedSinceString = $_ENV[self::HTTP_IF_MODIFIED_SINCE];
        } else {
            $modifiedSinceString = null;
        }

        if ($modifiedSinceString) {
            // Some versions of IE 6 append "; length=##"
            if (($pos = strpos($modifiedSinceString, ';')) !== false) {
                $modifiedSinceString = substr($modifiedSinceString, 0, $pos);
            }

            return strtotime($modifiedSinceString);
        }

        return false;
    }
private function getIfModifiedSinceTimestamp ( ) { if ( ! empty ( $ _SERVER [ self :: HTTP_IF_MODIFIED_SINCE ] ) ) { $ modifiedSinceString = $ _SERVER [ self :: HTTP_IF_MODIFIED_SINCE ] ; } elseif ( ! empty ( $ _ENV [ self :: HTTP_IF_MODIFIED_SINCE ] ) ) { $ modifiedSinceString = $ _ENV [ self :: HTTP_IF_MODIFIED_SINCE ] ; } else { $ modifiedSinceString = null ; } if ( $ modifiedSinceString ) { // Some versions of IE 6 append "; length=##" if ( ( $ pos = strpos ( $ modifiedSinceString , ';' ) ) !== false ) { $ modifiedSinceString = substr ( $ modifiedSinceString , 0 , $ pos ) ; } return strtotime ( $ modifiedSinceString ) ; } return false ; }
Get timestamp value from If-Modified-Since request header

@return false|int Timestamp or false when header not found
Get timestamp value from If - Modified - Since request header