src/main/java/com/netiq/websockify/WebsockifyProxyHandler.java
private void setDateAndCacheHeaders(HttpResponse response, File fileToCache) {
        SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
        dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));

        // Date header
        Calendar time = new GregorianCalendar();
        response.setHeader(HttpHeaders.Names.DATE, dateFormatter.format(time.getTime()));

        // Add cache headers
        time.add(Calendar.SECOND, HTTP_CACHE_SECONDS);
        response.setHeader(HttpHeaders.Names.EXPIRES, dateFormatter.format(time.getTime()));
        response.setHeader(HttpHeaders.Names.CACHE_CONTROL, "private, max-age=" + HTTP_CACHE_SECONDS);
        response.setHeader(HttpHeaders.Names.LAST_MODIFIED, dateFormatter.format(new Date(fileToCache.lastModified())));
    }
private void setDateAndCacheHeaders(HttpResponse response, File fileToCache) {
        SimpleDateFormat dateFormatter = new SimpleDateFormat(HTTP_DATE_FORMAT, Locale.US);
        dateFormatter.setTimeZone(TimeZone.getTimeZone(HTTP_DATE_GMT_TIMEZONE));

        // Date header
        Calendar time = new GregorianCalendar();
        response.setHeader(HttpHeaders.Names.DATE, dateFormatter.format(time.getTime()));

        // Add cache headers
        time.add(Calendar.SECOND, HTTP_CACHE_SECONDS);
        response.setHeader(HttpHeaders.Names.EXPIRES, dateFormatter.format(time.getTime()));
        response.setHeader(HttpHeaders.Names.CACHE_CONTROL, "private, max-age=" + HTTP_CACHE_SECONDS);
        response.setHeader(HttpHeaders.Names.LAST_MODIFIED, dateFormatter.format(new Date(fileToCache.lastModified())));
    }
Sets the Date and Cache headers for the HTTP Response

@param response
HTTP response
@param fileToCache
file to extract content type