Piwik\Http::getModifiedSinceHeader PHP Method

getModifiedSinceHeader() public static method

Returns the If-Modified-Since HTTP header if it can be found. If it cannot be found, an empty string is returned.
public static getModifiedSinceHeader ( ) : string
return string
    public static function getModifiedSinceHeader()
    {
        $modifiedSince = '';
        if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE'])) {
            $modifiedSince = $_SERVER['HTTP_IF_MODIFIED_SINCE'];
            // strip any trailing data appended to header
            if (false !== ($semicolonPos = strpos($modifiedSince, ';'))) {
                $modifiedSince = substr($modifiedSince, 0, $semicolonPos);
            }
        }
        return $modifiedSince;
    }