为CAS单点登录服务器增加验证码功能

为CAS单点登录服务器增加验证码功能

2009-05-07 16:26

一、 利用CAS实现单点登录
二、 CAS客户端授权JDBC

三、 为CAS单点登录服务器增加验证码功能

四、 CAS RememberMe功能实现

添加jcaptcha.jar文件

web.xml：
增加

cas
/captcha.htm


login_webflow.xml：
  
      
      
      
  
替换为
   
     
     
     
   
增加
  
      
      
      
  

cas_servlet.xml：
增加
       captchaImageCreateController
          p:captchaService-ref="jcaptchaService"
      p:captchaValidationParameter="j_captcha_response"/>

   
     
   
   

       
           
       
       
           
       
       
            180
       
       
            100000
       
       
            75000
       
   

增加java类：
1、
package utils.captcha;
import com.octo.captcha.service.image.ImageCaptchaService;
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import java.io.ByteArrayOutputStream;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.*;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

public class CaptchaImageCreateController implements Controller, InitializingBean {
   private ImageCaptchaService jcaptchaService;
   public CaptchaImageCreateController(){
   }
   public ModelAndView handleRequest(HttpServletRequest request,HttpServletResponse response) throws Exception {
      byte captchaChallengeAsJpeg[] = null;
      ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
      String captchaId = request.getSession().getId();
      java.awt.image.BufferedImage challenge=jcaptchaService.getImageChallengeForID(captchaId,request.getLocale());
      JPEGImageEncoder jpegEncoder = JPEGCodec.createJPEGEncoder(jpegOutputStream);

      jpegEncoder.encode(challenge);
      captchaChallengeAsJpeg = jpegOutputStream.toByteArray();response.setHeader("Cache-Control", "no-store");
      response.setHeader("Pragma", "no-cache");
      response.setDateHeader("Expires", 0L);
      response.setContentType("image/jpeg");
      ServletOutputStream responseOutputStream = response.getOutputStream();
      responseOutputStream.write(captchaChallengeAsJpeg);
      responseOutputStream.flush();
      responseOutputStream.close();
      return null;
   }
   public void setJcaptchaService(ImageCaptchaService jcaptchaService) {
      this.jcaptchaService = jcaptchaService;
   }
   public void afterPropertiesSet() throws Exception {
      if(jcaptchaService == null)
         throw new RuntimeException("Image captcha service wasn`t set!");
      else
         return;
   }
}

2、
package utils.captcha;
import org.jasig.cas.web.support.WebUtils;
import org.springframework.webflow.action.AbstractAction;
import org.springframework.webflow.execution.Event;
import org.springframework.webflow.execution.RequestContext;

import com.octo.captcha.service.CaptchaServiceException;
import com.octo.captcha.service.image.ImageCaptchaService;

public final class CaptchaValidateAction extends AbstractAction {
   private ImageCaptchaService jcaptchaService;
   private String captchaValidationParameter = "_captcha_parameter";
   protected Event doExecute(final RequestContext context) {
      String captcha_response = context.getRequestParameters().get(captchaValidationParameter);
      boolean valid = false;

      if(captcha_response != null){
         String id = WebUtils.getHttpServletRequest(context).getSession().getId();
         if(id != null){
            try {
               valid = jcaptchaService.validateResponseForID(id,captcha_response).booleanValue();
            } catch (CaptchaServiceException cse) {
            }
         }
      }

      if(valid){
         return success();
      }
      return error();
   }

   public void setCaptchaService(ImageCaptchaService captchaService) {
      this.jcaptchaService = captchaService;
   }

   public void setCaptchaValidationParameter(String captchaValidationParameter) {
      this.captchaValidationParameter = captchaValidationParameter;
   }
}

3、
package utils.captcha;
import java.awt.Color;
import java.awt.Font;

import com.octo.captcha.component.image.backgroundgenerator.BackgroundGenerator;
import com.octo.captcha.component.image.backgroundgenerator.GradientBackgroundGenerator;
import com.octo.captcha.component.image.color.SingleColorGenerator;
import com.octo.captcha.component.image.fontgenerator.FontGenerator;
import com.octo.captcha.component.image.textpaster.DecoratedRandomTextPaster;
import com.octo.captcha.component.image.textpaster.TextPaster;
import com.octo.captcha.component.image.textpaster.textdecorator.BaffleTextDecorator;
import com.octo.captcha.component.image.textpaster.textdecorator.LineTextDecorator;
import com.octo.captcha.component.image.textpaster.textdecorator.TextDecorator;
import com.octo.captcha.component.image.wordtoimage.ComposedWordToImage;
import com.octo.captcha.component.image.wordtoimage.WordToImage;
import com.octo.captcha.component.word.wordgenerator.RandomWordGenerator;
import com.octo.captcha.component.word.wordgenerator.WordGenerator;
import com.octo.captcha.engine.image.ListImageCaptchaEngine;
import com.octo.captcha.image.gimpy.GimpyFactory;

public class JCaptchaEngineEx extends ListImageCaptchaEngine {

    protected void buildInitialFactories() {
        /**
         * Set Captcha Word Length Limitation which should not over 6
         */
        Integer minAcceptedWordLength = new Integer(4);
        Integer maxAcceptedWordLength = new Integer(4);
        /**
         * Set up Captcha Image Size: Height and Width
         */
        Integer imageHeight = new Integer(28);
        Integer imageWidth = new Integer(75);
        /**
         * Set Captcha Font Size between 50 and 55
         */
        final Integer minFontSize = new Integer(22);
        final Integer maxFontSize = new Integer(22);
        /**
         * We just generate digit for captcha source char
         * Although you can use abcdefg......xyz
         */
        WordGenerator wordGenerator = (new RandomWordGenerator("0123456789"));
        /**
         * cyt and unruledboy proved that backgroup not a factor of Security.
         * A captcha attacker won't affaid colorful backgroud, so we just use
         * white color, like google and hotmail.
         */
        Color bgColor = new Color(255, 255, 255);
        BackgroundGenerator backgroundGenerator = new GradientBackgroundGenerator(
                imageWidth, imageHeight, bgColor, bgColor);
        /**
         * font is not helpful for security but it really increase difficultness for attacker
         */
        FontGenerator _fontGenerator = new FontGenerator() {
           public Font getFont() {
               return new Font("Arial", Font.ITALIC, 16);
           }
           public int getMinFontSize() {
               return minFontSize.intValue();
           }
           public int getMaxFontSize() {
               return maxFontSize.intValue();
           }
        };
        /**
         * Note that our captcha color is Blue
         */
        SingleColorGenerator scg = new SingleColorGenerator(Color.BLACK);
        /**
         * decorator is very useful pretend captcha attack.
         * we use two line text decorators.
         */
        LineTextDecorator line_decorator = new LineTextDecorator(new Integer(1), Color.blue);
        LineTextDecorator line_decorator2 = new LineTextDecorator(new Integer(1), Color.blue);
        TextDecorator[] textdecorators = new TextDecorator[2];

        textdecorators[0] = line_decorator;
        textdecorators[1] = line_decorator2;

        TextPaster _textPaster = new DecoratedRandomTextPaster(minAcceptedWordLength,
                maxAcceptedWordLength, scg, new TextDecorator[]{new BaffleTextDecorator(new Integer(0), Color.white)});

        /**
         * ok, generate the WordToImage Object for logon service to use.
         */
        WordToImage wordToImage = new ComposedWordToImage(
               _fontGenerator, backgroundGenerator, _textPaster);
      
        addFactory(new GimpyFactory(wordGenerator, wordToImage));
    }


}

登录的jsp页面：
增加

http://hi.baidu.com/aaspace/blog/item/c87b961803e578bc4bedbc6e.html