Re: Captcha in Struts2

["matt.payne" <ma...@gmail.com>]

aarthy wrote:
> 
> How Can I implement Captcha in Struts2? 
> 

see http://code.google.com/p/kaptcha/

I put the logic in a KaptchInterceptor so actions don't need to be aware of
this lib or validation.

Here is the crux of the logic for that interceptor.

<interceptor name="captcha"
				class="com.pennmutual.common.struts2.interceptors.KaptchaInterceptor">
				<!-- input -->
			</interceptor>

      //  default name of field on submissions that contains the kaptcha
answer
	private static final String FIELD_NAME = "kaptcha";
	String fieldName = FIELD_NAME;

public String getFieldName() {
		return fieldName;
	}

	public void setFieldName(String fieldName) {
		this.fieldName = fieldName;
	}
	public String intercept(ActionInvocation invocation) throws Exception {

		Object kaptchaExpected = ActionContext.getContext().getSession().get(
				com.google.code.kaptcha.Constants.KAPTCHA_SESSION_KEY);
		final Map params = ActionContext.getContext().getParameters();
	    final ActionContext context = invocation.getInvocationContext();
		
		HttpServletRequest request = (HttpServletRequest)
context.get(HTTP_REQUEST);
		
		if (params.containsKey(fieldName)) {
			String kaptchaAnswer = (String) request.getParameter(fieldName);
			if (kaptchaAnswer.equals(kaptchaExpected)) {
					log.debug("found kaptcha answer");
					return invocation.invoke();
			}
			attemptAddErrorToAction(invocation, "captcha.invalid");
			return failResult;  //maybe just input
		} else {
			log.debug("Kaptcha form submission did not contain a field named:" +
fieldName);
			attemptAddErrorToAction(invocation, "captcha.missing");
			return failResult;  //maybe error

		}

	}

	private void attemptAddErrorToAction(ActionInvocation i, String msgKey) {
		Object a = i.getAction();

		if (a instanceof ValidationAware) {
			ValidationAware v = (ValidationAware) a;
			String message;
			message = msgKey; // message becomes the key by default
			if (a instanceof TextProvider) {
				message = ((TextProvider) a).getText(msgKey);
				if (message.length() == 0 || message.equals(msgKey)) {
					log.debug("message: " + msgKey + " not found");
					message = msgKey; // just send the plain key to the interface
				}
			}
			v.addActionError(message);
		}

	}
Also, here is what the usage looks like on a form.

 <label for="kaptcha">Type the code:</label> <input type="text"
name="kaptcha" value=""  size="10" maxlength="6"/><br/>
            	<div class="tuckedIn" >
         		 ${base}/kaptcha <br/> 
					 #ImageFieldSet <@s.text name="label.captcha.refresh"/> 
					<script type="text/javascript">
    				$(function(){
        				$('#refreshLink').click(function () { $('#captcha').attr('src',
'${base}/kaptcha?' + Math.floor(Math.random()*100) ); })
    				});
					</script>
				 
          		</div>
(jquery used in that javascript above).

I also, use jquery's validation library and do ajax captcha validation in
addition to back end checking, but I'll leave those details out until you
have the basics working.  
-- 
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