a cai 雜記: Get Random Word in the JCaptcha

這裡的JCaptcha指的是整合在Jasig CAS，相關設定可參考另一篇 JCaptcha integration with CAS 這裡的測試也會延續這一篇的設定。因有追查在某些裝置上驗證碼會無效的需求，需要 log 產生在登入頁的驗證碼及 User 輸入的驗證碼，以查出問題之所在，查詢 JCaptcha API 後發現沒有 interface 可取得已產出的驗證碼，同樣求神問卜後找到這一篇使用 JCaptcha 開發圖形和聲音驗證碼，因同時使用圖形及聲音驗證所以需要驗證碼一致，透過 override API 的方式來取得產出的驗證碼，主要是參考這一篇文章將取得驗證碼整合至 Jasig CAS 及 JCaptcha 以達到目的。

使用 JCaptcha 開發圖形和聲音驗證碼有提供 SourceCode ，會直接下載來整合進 Jasig CAS 和 JCaptcha，如果只是修改 package 則不再列出，build cas-server-core 也請參考另一篇的說明。

準備執行環境

Maven是為 build JCaptcha integration with CAS 做準備

JDK (Java Development Kit) version 1.6+
Apache Maven 2.2.1+
Apache Tomcat 6+
JA-SIG CAS 3.4.2.1+
JCaptcha 1.0

下載 Sample

下載 SourceCode並解壓縮。

Build & Running JCaptcha Sample integration with CAS

將 Sample 整合至 CAS 可參考以下二張圖的對照，因不想 CAS 的相關設定改變太多，所以選擇修改 Sample 的 package 架構，不然依測試的經驗此 Sample 不用修改即可運作；保留另一篇 JCaptcha integration with CAS 文章中的CaptchaServiceSingleton.java 及 ImageCaptchaServlet.java，因此 Sample 複製到 CAS 會有以下的對應修改，另外只處理圖形驗證碼所以聲音驗證的相關 Java file 不用複製。

com\sample\jcaptcha\service\SampleImageCaptchaService.java --> org\jasig\cas\captcha\CaptchaServiceSingleton.java

com\sample\jcaptcha\servlet\ImageCaptchaServlet.java --> org\jasig\cas\captcha\ImageCaptchaServlet.java

cas-server-3.4.3\cas-server-core\src\main\java\org\jasig\cas\captcha\factory\SampleGimpyFactory.java line-37 在產生驗證碼的圖檔之前先取得驗證碼的文字。

package org.jasig.cas.captcha.factory;

import java.awt.image.BufferedImage;
import java.util.Locale;

import com.octo.captcha.CaptchaException;
import com.octo.captcha.CaptchaQuestionHelper;
import com.octo.captcha.component.image.wordtoimage.WordToImage;
import com.octo.captcha.component.word.wordgenerator.WordGenerator;
import com.octo.captcha.image.ImageCaptcha;
import com.octo.captcha.image.gimpy.GimpyFactory;
import org.jasig.cas.captcha.service.WordBridge;

/**
 * Sample Gimpy Factory
 * @author guangqingzhong
 *
 */
public class SampleGimpyFactory extends GimpyFactory {
 
    private WordBridge wordBridge = new WordBridge();

 
    public SampleGimpyFactory(WordGenerator generator, WordToImage word2image) {
        super(generator, word2image);
    }
  

    public SampleGimpyFactory(WordGenerator generator, WordToImage word2image, WordBridge wordBridge) {
        super(generator, word2image);
    }

    public ImageCaptcha getImageCaptcha(Locale locale) {
        //length
        Integer wordLength = getRandomLength();

        String word = getWordGenerator().getWord(wordLength, locale);
        if (this.wordBridge != null) {
            this.wordBridge.setGeneratedWord(word);
        }
        BufferedImage image = null;
        try {
            image = getWordToImage().getImage(word);
        } catch (Throwable e) {
            throw new CaptchaException(e);
        }

        ImageCaptcha captcha = new
            SampleGimpy(CaptchaQuestionHelper.getQuestion(locale, 
                                BUNDLE_QUESTION_KEY),
                        image, word);

        return captcha;
    }

    public WordBridge getWordBridge() {
        return this.wordBridge ;
    }
}

cas-server-3.4.3\cas-server-core\src\main\java\org\jasig\cas\captcha\engin\SampleListImageCaptchaEngine.java 有修改成亂數取背景圖的方式，不是完全照 Sample 處理，line-57 可看到 Create Image 是使用 SampleGimpyFactory object，再透過 WordBridge object 取得驗證碼的文字，line-65 則是之前產生驗證碼圖片的方式。

package org.jasig.cas.captcha.engine;

import java.awt.Color;
import java.awt.Font;

import com.octo.captcha.component.image.backgroundgenerator.FunkyBackgroundGenerator;
import com.octo.captcha.component.image.backgroundgenerator.FileReaderRandomBackgroundGenerator;
import com.octo.captcha.component.image.color.SingleColorGenerator;
import com.octo.captcha.component.image.fontgenerator.TwistedRandomFontGenerator;
import com.octo.captcha.component.image.fontgenerator.FontGenerator;
import com.octo.captcha.component.image.fontgenerator.RandomFontGenerator;
import com.octo.captcha.component.image.textpaster.DecoratedRandomTextPaster;
import com.octo.captcha.component.image.textpaster.TextPaster;
import com.octo.captcha.component.image.textpaster.RandomTextPaster;
import com.octo.captcha.component.image.textpaster.textdecorator.BaffleTextDecorator;
import com.octo.captcha.component.image.textpaster.textdecorator.TextDecorator;
import com.octo.captcha.component.image.wordtoimage.ComposedWordToImage;
import com.octo.captcha.component.word.wordgenerator.RandomWordGenerator;
import com.octo.captcha.engine.image.ListImageCaptchaEngine;
import com.octo.captcha.image.ImageCaptchaFactory;
import org.jasig.cas.captcha.factory.SampleGimpyFactory;
import org.jasig.cas.captcha.service.WordBridge;

/**
 * Sample Image Engine
 * 
 * @author guangqingzhong
 * 
 */
public class SampleListImageCaptchaEngine extends ListImageCaptchaEngine {
    private WordBridge wordBridge;
 

    public SampleListImageCaptchaEngine() {
        super();
    }


    protected void buildInitialFactories() {

        FileReaderRandomBackgroundGenerator background = new FileReaderRandomBackgroundGenerator(new Integer(180), new Integer(50),"../webapps/cas/images/backgrounds/");


        Font[] fontsList = new Font[] {
            new Font("Arial", 0, 10),
            new Font("Tahoma", 0, 10),
            new Font("Verdana", 0, 10),
        };

        FontGenerator fontGenerator = new RandomFontGenerator(new Integer(30), new Integer(30), fontsList);

        //create text parser
        TextPaster randomPaster = new RandomTextPaster(new Integer(6),
            new Integer(6), new SingleColorGenerator(Color.BLACK), true);

        //create image captcha factory
        ImageCaptchaFactory factory = new SampleGimpyFactory(
            new RandomWordGenerator("abcdefghijklmnopqrstuvwxyz0123456789"),
            new ComposedWordToImage(fontGenerator, background, randomPaster));

        wordBridge = ((SampleGimpyFactory)factory).getWordBridge();
  
        ImageCaptchaFactory characterFactory[] = { factory};
        this.addFactories(characterFactory);
        //this.addFactory(new GimpyFactory(wgen, wordToImage));
    }

    public WordBridge getWordBridge() {
        return wordBridge;
    }
}

cas-server-3.4.3\cas-server-core\src\main\java\org\jasig\cas\captcha\CaptchaServiceSingleton.java 前一篇文章是將這一支程式同時實作 ImageCaptchaService 和 ImageCaptchaEngine 的功能，現在則採用 Sample 的方式各自實作，這裡取得 Image Buffer 後會以 sessionID 為 Key 將驗證碼文字放到 WordMap object (line - 47)，另外為了 CAS 判斷驗證碼的方便性，將 CaptchaServiceSingleton 改為 ImageCaptchaService line - 20、25。

package org.jasig.cas.captcha;

import java.awt.image.BufferedImage;

import com.octo.captcha.engine.CaptchaEngine;
import com.octo.captcha.engine.image.ListImageCaptchaEngine;
import com.octo.captcha.service.CaptchaServiceException;
import com.octo.captcha.service.captchastore.CaptchaStore;
import com.octo.captcha.service.captchastore.FastHashMapCaptchaStore;
import com.octo.captcha.service.image.AbstractManageableImageCaptchaService;
import com.octo.captcha.service.image.ImageCaptchaService;
import org.jasig.cas.captcha.engine.SampleListImageCaptchaEngine;
import org.jasig.cas.captcha.service.WordMap;
import org.jasig.cas.captcha.service.WordBridge;

public class CaptchaServiceSingleton extends
  AbstractManageableImageCaptchaService implements ImageCaptchaService {

    //private static CaptchaServiceSingleton instance;
    private static ImageCaptchaService instance;

    private static ListImageCaptchaEngine engine;

    //public static CaptchaServiceSingleton getInstance() {
    public static ImageCaptchaService getInstance() {
        if (instance == null) {
            engine = new SampleListImageCaptchaEngine();
            instance = new CaptchaServiceSingleton(
                        new FastHashMapCaptchaStore(), engine, 180, 1000, 750);
        }
        return instance;
    }

    public CaptchaServiceSingleton(CaptchaStore captchaStore,
            CaptchaEngine captchaEngine, int minGuarantedStorageDelayInSeconds,
            int maxCaptchaStoreSize, int captchaStoreLoadBeforeGarbageCollection) {
        super(captchaStore, captchaEngine, minGuarantedStorageDelayInSeconds,
            maxCaptchaStoreSize, captchaStoreLoadBeforeGarbageCollection);
    }

    @Override
    public BufferedImage getImageChallengeForID(String ID)
            throws CaptchaServiceException {
        BufferedImage image=  super.getImageChallengeForID(ID);
        String generatedWord = ((SampleListImageCaptchaEngine) engine).
            getWordBridge().getGeneratedWord();
        WordMap.getWordsMap().put(ID, generatedWord);
        return image;
    }
}

修改cas-server-3.4.3\cas-server-core\src\main\java\org\jasig\cas\web\flow\AuthenticationViaFormAction.java，於驗證錯誤時將登入前後的驗證碼文字 print 出來，參考 line-30 ~ 32 。

import com.octo.captcha.service.CaptchaServiceException;
import org.jasig.cas.captcha.CaptchaServiceSingleton;
import org.jasig.cas.captcha.service.WordMap;
....

    public final String submit(final RequestContext context, final Credentials credentials, final MessageContext messageContext) throws Exception {
        final String ticketGrantingTicketId = WebUtils.getTicketGrantingTicketId(context);
        final Service service = WebUtils.getService(context);

        // for captcha check input and expect value begin
        final HttpServletRequest request = WebUtils.getHttpServletRequest(context);
        Boolean isResponseCorrect = Boolean.FALSE;
        String enterCaptchaId = request.getParameter( "j_captcha_response" );
        String captchaId = request.getSession().getId();

....

        try {
            //WebUtils.putTicketGrantingTicketInRequestScope(context, this.centralAuthenticationService.createTicketGrantingTicket(credentials));
            //putWarnCookieIfRequestParameterPresent(context);
            //return "success";

            // for captcha
            if( Boolean.TRUE.equals(isResponseCorrect) ) { 
                WebUtils.putTicketGrantingTicketInRequestScope(context, this.centralAuthenticationService.createTicketGrantingTicket(credentials));
                putWarnCookieIfRequestParameterPresent(context);
                return "success";
            } else {
                // for captcha, captcha validate failed
                System.out.println("Session ID=" + captchaId);
                System.out.println("generated word=" + WordMap.getWordsMap().get(captchaId));
                System.out.println("j_captcha_response=" + enterCaptchaId);

                messageContext.addMessage( new MessageBuilder().error().code( "captcha.input.error" ).defaultText( "captcha.input.error" ).build() );
                return "error"; 
            }// for captcha 

        } catch (final TicketException e) {
            populateErrorsInstance(e, messageContext);
            return "error";
        }
    }

build cas-server-core-3.4.3.jar，切換到 cas-server-3.4.3\cas-server-core 路徑執行下列指令，將產出的cas-server-core-3.4.3.jar複製到cas\WEB-INF\lib此路徑下。

mvn clean package -Dmaven.test.skip=true

啟動 Tomcat ，連結至CAS Login Page，輸入錯誤的驗證碼，可看到以下的 log，驗證碼為e4ct0a第一次出現時是進入登入頁時，第二次出現時是按登入驗證後，123456是故意輸錯的驗證碼。

測試驗證碼一直出現錯誤的裝置，可看到以下的 log，於登入頁顯示的驗證碼為691152，但 Server 已經產生第二組驗證碼053171了，造成驗證碼不符無法登入成功，經高人指點是因為 Browser 的行為造成的，可看相關參考的連結，說明的相當清楚就不再重覆了。

a cai 雜記

2012年10月17日星期三

Get Random Word in the JCaptcha

準備執行環境

Build & Running JCaptcha Sample integration with CAS

沒有留言:

張貼留言

2012年10月17日 星期三

Get Random Word in the JCaptcha

準備執行環境

Build & Running JCaptcha Sample integration with CAS

沒有留言:

張貼留言

2012年10月17日星期三