Java tutorial
/* * File : $Source: /alkacon/cvs/alkacon/com.alkacon.opencms.formgenerator/src/com/alkacon/opencms/formgenerator/CmsCaptchaField.java,v $ * Date : $Date: 2011/03/09 15:14:35 $ * Version: $Revision: 1.12 $ * * This file is part of the Alkacon OpenCms Add-On Module Package * * Copyright (c) 2010 Alkacon Software GmbH (http://www.alkacon.com) * * The Alkacon OpenCms Add-On Module Package is free software: * you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * The Alkacon OpenCms Add-On Module Package is distributed * in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with the Alkacon OpenCms Add-On Module Package. * If not, see http://www.gnu.org/licenses/. * * For further information about Alkacon Software GmbH, please see the * company website: http://www.alkacon.com. * * For further information about OpenCms, please see the * project website: http://www.opencms.org. */ package com.alkacon.opencms.formgenerator; import org.opencms.flex.CmsFlexController; import org.opencms.i18n.CmsMessages; import org.opencms.jsp.CmsJspActionElement; import org.opencms.main.CmsLog; import org.opencms.util.CmsStringUtil; import java.awt.image.BufferedImage; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.util.HashMap; import java.util.Locale; import java.util.Map; import javax.imageio.ImageIO; import javax.servlet.ServletOutputStream; import javax.servlet.http.HttpServletResponse; import org.apache.commons.logging.Log; import com.octo.captcha.CaptchaException; import com.octo.captcha.service.CaptchaService; import com.octo.captcha.service.CaptchaServiceException; import com.octo.captcha.service.image.ImageCaptchaService; import com.octo.captcha.service.text.TextCaptchaService; /** * Creates captcha images and validates the pharses submitted by a request parameter. * <p> * * @author Thomas Weckert * * @author Achim Westermann * * @version $Revision: 1.12 $ * * @since 7.0.4 */ public class CmsCaptchaField extends A_CmsField { /** Request parameter name of the captcha phrase. */ public static final String C_PARAM_CAPTCHA_PHRASE = "captchaphrase"; /** Session parameter name to store the webform captcha settings. */ protected static final String SESSION_PARAM_CAPTCHASETTINGS = "__oamp_webform_captchasettings"; /** The log object for this class. */ private static final Log LOG = CmsLog.getLog(CmsCaptchaField.class); /** HTML field type: captcha image. */ private static final String TYPE = "captcha"; /** The settings to render captcha images. */ private CmsCaptchaSettings m_captchaSettings; /** * Creates a new captcha field. * <p> * * @param captchaSettings the settings to render captcha images * @param fieldLabel the localized label of this field * @param fieldValue the submitted value of this field */ public CmsCaptchaField(CmsCaptchaSettings captchaSettings, String fieldLabel, String fieldValue) { super(); m_captchaSettings = captchaSettings; setName(C_PARAM_CAPTCHA_PHRASE); setValue(fieldValue); setLabel(fieldLabel); setMandatory(true); } /** * Returns the type of the input field, e.g. "text" or "select". * <p> * * @return the type of the input field */ public static String getStaticType() { return TYPE; } /** * @see com.alkacon.opencms.formgenerator.I_CmsField#buildHtml(CmsFormHandler, CmsMessages, String, boolean, String) */ @Override public String buildHtml(CmsFormHandler formHandler, CmsMessages messages, String errorKey, boolean showMandatory, String infoKey) { StringBuffer captchaHtml = new StringBuffer(256); String errorMessage = createStandardErrorMessage(errorKey, messages); CmsCaptchaSettings captchaSettings = getCaptchaSettings(); if (m_captchaSettings.isMathField()) { // this is a math captcha, print the challenge directly String sessionId = formHandler.getRequest().getSession(true).getId(); TextCaptchaService service = (TextCaptchaService) CmsCaptchaServiceCache.getSharedInstance() .getCaptchaService(m_captchaSettings, formHandler.getCmsObject()); captchaHtml.append("<div style=\"margin: 0 0 2px 0;\">"); captchaHtml.append(service.getTextChallengeForID(sessionId, formHandler.getCmsObject().getRequestContext().getLocale())); captchaHtml.append("</div>\n"); } else { // image captcha, insert image captchaHtml.append("<img id=\"form_captcha_id\" src=\"") .append(formHandler.link("/system/modules/com.alkacon.opencms.formgenerator/pages/captcha.jsp?" + captchaSettings.toRequestParams(formHandler.getCmsObject()) + "#" + System.currentTimeMillis())) .append("\" width=\"").append(captchaSettings.getImageWidth()).append("\" height=\"") .append(captchaSettings.getImageHeight()).append("\" alt=\"\"/>").append("\n"); captchaHtml.append("<br/>\n"); } Map<String, Object> stAttributes = new HashMap<String, Object>(); // set captcha HTML code as additional attribute stAttributes.put("captcha", captchaHtml.toString()); return createHtml(formHandler, messages, stAttributes, getType(), null, errorMessage, showMandatory); } /** * Returns the captcha settings of this field. * <p> * * @return the captcha settings of this field */ public CmsCaptchaSettings getCaptchaSettings() { return m_captchaSettings; } /** * @see com.alkacon.opencms.formgenerator.I_CmsField#getType() */ public String getType() { return TYPE; } /** * Validates the captcha phrase entered by the user. * <p> * * @param jsp the Cms JSP * @param captchaPhrase the captcha phrase to be validate * @return true, if the captcha phrase entered by the user is correct, false otherwise */ public boolean validateCaptchaPhrase(CmsJspActionElement jsp, String captchaPhrase) { boolean result = false; CmsCaptchaSettings settings = m_captchaSettings; // check if there are changed captcha settings stored in the session (true if first image generation failed) CmsCaptchaSettings sessionSettings = (CmsCaptchaSettings) jsp.getRequest().getSession() .getAttribute(SESSION_PARAM_CAPTCHASETTINGS); if (sessionSettings != null) { // use captcha settings from session to validate the response settings = sessionSettings; jsp.getRequest().getSession().removeAttribute(SESSION_PARAM_CAPTCHASETTINGS); } String sessionId = jsp.getRequest().getSession().getId(); if (CmsStringUtil.isNotEmpty(captchaPhrase)) { // try to validate the phrase try { CaptchaService captchaService = CmsCaptchaServiceCache.getSharedInstance() .getCaptchaService(settings, jsp.getCmsObject()); if (captchaService != null) { result = captchaService.validateResponseForID(sessionId, captchaPhrase).booleanValue(); } } catch (CaptchaServiceException cse) { // most often this will be // "com.octo.captcha.service.CaptchaServiceException: Invalid ID, could not validate unexisting or already validated captcha" // in case someone hits the back button and submits again } } return result; } /** * Writes a Captcha JPEG image to the servlet response output stream. * <p> * * @param cms an initialized Cms JSP action element * @throws IOException if something goes wrong */ public void writeCaptchaImage(CmsJspActionElement cms) throws IOException { // remove eventual session attribute containing captcha settings cms.getRequest().getSession().removeAttribute(SESSION_PARAM_CAPTCHASETTINGS); String sessionId = cms.getRequest().getSession().getId(); Locale locale = cms.getRequestContext().getLocale(); BufferedImage captchaImage = null; int maxTries = 10; do { try { maxTries--; captchaImage = ((ImageCaptchaService) CmsCaptchaServiceCache.getSharedInstance() .getCaptchaService(m_captchaSettings, cms.getCmsObject())).getImageChallengeForID(sessionId, locale); } catch (CaptchaException cex) { // image size is too small, increase dimensions and try it again if (LOG.isInfoEnabled()) { LOG.info(cex); LOG.info(Messages.get().getBundle().key(Messages.LOG_ERR_CAPTCHA_CONFIG_IMAGE_SIZE_2, new Object[] { m_captchaSettings.getPresetPath(), new Integer(maxTries) })); } m_captchaSettings.setImageHeight((int) (m_captchaSettings.getImageHeight() * 1.1)); m_captchaSettings.setImageWidth((int) (m_captchaSettings.getImageWidth() * 1.1)); // IMPORTANT: store changed captcha settings in session, they have to be used when validating the phrase cms.getRequest().getSession().setAttribute(SESSION_PARAM_CAPTCHASETTINGS, m_captchaSettings.clone()); } } while ((captchaImage == null) && (maxTries > 0)); ServletOutputStream out = null; try { CmsFlexController controller = CmsFlexController.getController(cms.getRequest()); HttpServletResponse response = controller.getTopResponse(); response.setHeader("Cache-Control", "no-store"); response.setHeader("Pragma", "no-cache"); response.setDateHeader("Expires", 0); response.setContentType("image/jpeg"); ByteArrayOutputStream captchaImageOutput = new ByteArrayOutputStream(); ImageIO.write(captchaImage, "jpg", captchaImageOutput); out = cms.getResponse().getOutputStream(); out.write(captchaImageOutput.toByteArray()); out.flush(); } catch (Exception e) { if (LOG.isErrorEnabled()) { LOG.error(e.getLocalizedMessage(), e); } cms.getResponse().sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); } finally { try { if (out != null) { out.close(); } } catch (Throwable t) { // intentionally left blank } } } }