Using kaptcha with JSF - jsf

Question

I'm trying to use http://code.google.com/p/kaptcha/ which looks like a very easy way to include CAPTCHA. My demo app is JSF and although the instructions are simple for JSP, I don't know how to use them in JSF. How do I translate this in JSF?
In your code that manages the submit action:
String kaptchaExpected = (String)request.getSession()
.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
String kaptchaReceived = request.getParameter("kaptcha");
if (kaptchaReceived == null || !kaptchaReceived.equalsIgnoreCase(kaptchaExpected))
{
setError("kaptcha", "Invalid validation code.");
}
I tried putting it in my:
public String button1_action() {
// TODO: Process the action.
return "success";
}
but it doesn't understand the request object :(

Answer 1

This equivalent JSF action should do it:
// bind to <h:inputText value="#{thisbean.kaptchaReceived}" />
private String kaptchaReceived;
public String getKaptchaReceived() {
return kaptchaReceived;
}
public void setKaptchaReceived(String kaptcha) {
kaptchaReceived = kaptcha;
}
public String button1_action() {
if (kaptchaReceived != null) {
FacesContext context = FacesContext
.getCurrentInstance();
ExternalContext ext = context.getExternalContext();
Map<String, Object> session = ext.getSessionMap();
String kaptchaExpected = session
.get(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
if (kaptchaReceived.equalsIgnoreCase(kaptchaExpected)) {
return "success";
}
}
return "problem";
}
This assumes that you want to use h:inputText and h:graphicImage in your JSF view instead of HTML elements.

Answer 2

Implementing validator is another easy way to validate the kaptcha.
<h:inputText id="kaptcha" autocomplete="off" required="true">
<f:validator validatorId="kaptchaValidator" />
</h:inputText>
<h:message for="kaptcha" styleClass="errorMessage"/>
--- Validator ---
public class KaptchaValidator implements Validator {
#Override
public void validate(FacesContext facesContext, UIComponent uiComponent, Object value) throws ValidatorException {
HttpSession session = (HttpSession) facesContext.getExternalContext().getSession(true);
String kaptchaExpected = (String) session.getAttribute(com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
String kaptchaReceived = (String) value;
if (kaptchaReceived == null || !kaptchaReceived.equalsIgnoreCase(kaptchaExpected)) {
FacesMessage message = new FacesMessage();
message.setDetail("Invalid Security Code.");
message.setSummary("Invalid security code.");
message.setSeverity(FacesMessage.SEVERITY_INFO);
throw new ValidatorException(message);
}
}

Answer 3

You can retrieve the request object from the JSF External Context, which is accessible from the FacesContext, using the following code:
HttpServletRequest request = (HttpServletRequest) FacesContext.getCurrentInstance().getExternalContext().getRequest();
Edit (thanks to McDowell) :
Another way is to use the FacesContext.getCurrentInstance().getExternalContext().getRequestParameterMap() method to access the request parameters...