JCaptcha and Struts problem

[Em Aiy]

Hi,

I am using JCaptcha for captcha features. It is working fine. I have this code in CaptchaServlet and this code save the captcha in request

    public void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
 
ImageCaptcha pixCaptcha = factory.getImageCaptcha();
        BufferedImage bi = pixCaptcha.getImageChallenge();
        resp.setContentType("image/jpg");
        JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(resp.getOutputStream());
 
        jpegEncoder.encode(bi);
        resp.flushBuffer();
 
        req.getSession().setAttribute("pixCaptcha", pixCaptcha);
    }

Now, i get this captcha in form Action from req and validate it etc.

In that form i set the following header for the JSP page

response.setHeader("Pragma","no-cache"); //HTTP 1.0
response.setHeader("Cache-Control","no-cache"); //HTTP 1.1
response.setDateHeader ("Expires", 0); //pr

So that my captcha does not remain in cache. Now there is one issue. If i keep the page open for 10-15 minutes and after that i submit it, the actionform does not find any captcha (ok fine - make sense). The page is re-displayed but it display with the LAST CAPTCHA (it does not generate the new one) or at least generate the new one but does not show it.

So what coould be possible modification should i made so that my PAGE GURANTEE to show the new CAPTCHA IMAGE each time it loads (F5 or CTRL + F5).

[Jeanne Boyarsky]

Muhammad,
Is using POST an option? That would force a trip to the server where you could create a new captcha.

[Em Aiy]

I am using this code in CaptchaServlet POST method

public void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    ImageCaptcha pixCaptcha = (ImageCaptcha)(req.getSession().getAttribute("pixCaptcha"));
    if (pixCaptcha == null) {
        throw new UnexpectedException("No Captcha object found in session.");
    }
    if (pixCaptcha.validateResponse(req.getParameter("word")).booleanValue()) {        resp.getOutputStream().println("You are in");
    } else {
        resp.getOutputStream().println("Wrong choice,  retry.");
    }
}

Here is the code i have writen in action form, which validate the captcha

public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {

ActionErrors result = doStrutsValidations(mapping, request);
validateEmail(result);
validatePassword(result);

try {
ImageCaptcha pixCaptcha = (ImageCaptcha)(request.getSession().getAttribute("pixCaptcha"));
if (null != getCaptcha() && getCaptcha().length() > 0 && ! pixCaptcha.validateResponse(getCaptcha()).booleanValue()) {
result.add("captcha", new ActionMessage("errors.captcha"));
}
} catch(Exception ex) {
result.clear();
result.add("message", new ActionMessage("errors.unexpected"));
}
 
return result;
}

Now, when the exception occurs, it sends back to the url with "ERROR" message and it does not update the captcha (most of the time).