Question

Update: The issue is with the setting used for the MaxAge. Setting it to zero will cause the cookie to be deleted, hence it was shown in the response header but was then deleted and did not show in the request. Setting it to -1 so that it will not be stored persistently

I am doing some work on a filter in which I want it to set a cookie to indicate that the user qualifies to take a survey and that the next time he comes back to the site a survey popup window will be displayed.

I am not seeing any errors in the logs but the cookie never gets set.

Can a filter be used this way to add a cookie? Is there where a HttpServletResponseWrapper comes into play?

The thought here is that when the user comes to the the site there is a check to see if the cookie is present. If it is not then a cookie is created and added to the response. As the user navigates the site, the cookie check method is called to make sure that the hit counter is not increased for that given user.

The cookie check method never sees the cookie. Using web developer plugin for firefox, the cookie in question is not present.

Below is the filter class with the relevant methods.

public class HitCounterFilter extends TemplateFilter {
    public void doMainProcessing(ServletRequest pRequest, ServletResponse pResponse, FilterChain pChain) {
        HttpServletRequest httpRequest = (HttpServletRequest) pRequest;
        HttpServletResponse httpResponse = (HttpServletResponse) pResponse;

        // prevent thread interference and memory consistency errors
        synchronized (lock) {
            int hitCounter = this.readFile(localFile);

            // if user has not been counted
            if (!this.checkForCookie(httpRequest, "gtgo_visitor")) {
                this.writeFile(localFile, ++hitCounter);
                this.createCookie(httpRequest, httpResponse, String.valueOf(hitCounter), "gtgo_visitor");
            }
        }
    }

    private void createCookie(HttpServletRequest pHttpRequest, HttpServletResponse pHttpResponse, String pCookieValue, String pCookieName) {
        try {
            Cookie cookie = new Cookie(pCookieName, pCookieValue);
            URL url = new URL(pHttpRequest.getRequestURL().toString());
            cookie.setDomain(url.getHost());
            cookie.setPath(this.getCookiePath(pHttpRequest));
            cookie.setComment("user is not eligible to take the survey this time");
            cookie.setMaxAge(0);

            pHttpResponse.addCookie(cookie);
        } catch (MalformedURLException e) {
            e.printStackTrace();
        }
    }

    private boolean checkForCookie(HttpServletRequest pHttpRequest, String pCookieName) {
        for (Cookie cookie : pHttpRequest.getCookies()) {
            if (StringUtils.equalsIgnoreCase(cookie.getName(), pCookieName)) {
                return true;
            }
        }
        return false;
    }
} 

Answer 1

The issue is with the setting used for the MaxAge. Setting it to zero will cause the cookie to be deleted, hence it was shown in the response header but was then deleted and did not show in the request. Setting it to -1 so that it will not be stored persistently – it will be present as long as the session is active (removed once the session is closed)