SPAM 방어를 위한 jcaptcha 오픈소스 활용 방안

댓글이나 가입, 이메일 등에 SPAM 필터링을 위해서 Captcha기능을 적용하는 경우가 많습니다. 갤서 Java기반의 Open Source Captcha 기능을 적용하는 방안을 공유합니다.

1. 다운 로드
- http://jcaptcha.sourceforge.net/에서 라이브러리 다운하여 /WEB-INF/lib에 카피

2. web.xml 설정 추가

3. ImageCaptchaServlet.java 구성
- web.xml에 정의된 Servlet 구현

public class ImageCaptchaServlet extends HttpServlet 
{
	private static final long serialVersionUID = 1L;

public void init(ServletConfig servletConfig) throws ServletException 
	{
        super.init(servletConfig);
    }

protected void doGet(HttpServletRequest httpServletRequest, 
         HttpServletResponse httpServletResponse) throws ServletException, IOException {
        
        byte[] captchaChallengeAsJpeg = null;
        ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
        try {
	        String captchaId = httpServletRequest.getSession().getId();
	        //call the ImageCaptchaService getChallenge method
            BufferedImage challenge = CaptchaServiceSingleton.getInstance()
              .getImageChallengeForID(captchaId, httpServletRequest.getLocale());
            //a jpeg encoder
            JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(jpegOutputStream);
            jpegEncoder.encode(challenge);
        } catch (IllegalArgumentException e) {
            httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
            return;
        } catch (CaptchaServiceException e) {
            httpServletResponse.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR);
            return;
        }

captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
        // flush it in the response
        httpServletResponse.setHeader("Cache-Control", "no-store");
        httpServletResponse.setHeader("Pragma", "no-cache");
        httpServletResponse.setDateHeader("Expires", 0);
        httpServletResponse.setContentType("image/jpeg");
        ServletOutputStream responseOutputStream = httpServletResponse.getOutputStream();
        responseOutputStream.write(captchaChallengeAsJpeg);
        responseOutputStream.flush();
        responseOutputStream.close();
    }
}

4. CaptchaServiceSingleton.java 구성

5. SimpleListImageCaptchaEngine.java 구성

public class SimpleListImageCaptchaEngine extends ListImageCaptchaEngine 
{
    protected void buildInitialFactories() 
    {
        WordGenerator wordGenerator = new RandomWordGenerator("1234567890");
        SingleColorGenerator scg = new SingleColorGenerator(Color.blue);
        LineTextDecorator lineDecorator = new LineTextDecorator(1, Color.blue);
        TextDecorator[] textdecorators = new TextDecorator[1];
        textdecorators[0] = lineDecorator;
        TextPaster textPaster = new DecoratedRandomTextPaster(   
        		new Integer(4), new Integer(5), scg,   
                new TextDecorator[] { new BaffleTextDecorator(new Integer(1), Color.white) }); 
        BackgroundGenerator backgroundGenerator = 
          new GradientBackgroundGenerator(new Integer(140), new Integer(50), 
          Color.white, Color.white);//width,height
        FontGenerator fontGenerator = 
          new RandomFontGenerator(new Integer(28), new Integer(30));
        
        WordToImage wordToImage = 
         new ComposedWordToImage(fontGenerator, backgroundGenerator, textPaster); 
        this.addFactory(new GimpyFactory(wordGenerator,wordToImage));
    }
}

6. SPAM 적용할 페이지 추가

7. 체크 Action

8. 적용 화면

코멘트 달기

Posted by 미물 on 2008년 2월 1일 (금) 오후 11시 27분 00초 #

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