Java tutorial
/* * This library is part of OpenCms - * the Open Source Content Management System * * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com) * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library 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 * Lesser General Public License for more details. * * 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 * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package org.opencms.main; import org.opencms.file.CmsFile; import org.opencms.file.CmsObject; import org.opencms.file.CmsResource; import org.opencms.file.CmsResourceFilter; import org.opencms.i18n.CmsMessageContainer; import org.opencms.staticexport.CmsStaticExportData; import org.opencms.staticexport.CmsStaticExportRequest; import org.opencms.util.CmsRequestUtil; import java.io.IOException; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.logging.Log; /** * This the main servlet of the OpenCms system.<p> * * From here, all operations that are results of HTTP requests are invoked. * Any incoming request is handled in multiple steps: * * <ol><li>The requesting <code>{@link org.opencms.file.CmsUser}</code> is authenticated * and a <code>{@link org.opencms.file.CmsObject}</code> with this users context information * is created. This <code>{@link org.opencms.file.CmsObject}</code> is used to access all functions of OpenCms, limited by * the authenticated users permissions. If the user is not identified, it is set to the default user, usually named "Guest".</li> * * <li>The requested <code>{@link org.opencms.file.CmsResource}</code> is loaded into OpenCms and depending on its type * (and the users persmissions to display or modify it), * it is send to one of the OpenCms <code>{@link org.opencms.loader.I_CmsResourceLoader}</code> implementations * do be processed.</li> * * <li> * The <code>{@link org.opencms.loader.I_CmsResourceLoader}</code> will then decide what to do with the * contents of the requested <code>{@link org.opencms.file.CmsResource}</code>. * In case of a JSP resource the JSP handling mechanism is invoked with the <code>{@link org.opencms.loader.CmsJspLoader}</code>, * in case of an image (or another static resource) this will be returned by the <code>{@link org.opencms.loader.CmsDumpLoader}</code> * etc. * </li></ol> * * @since 6.0.0 * * @see org.opencms.main.CmsShell * @see org.opencms.file.CmsObject * @see org.opencms.main.OpenCms */ public class OpenCmsServlet extends HttpServlet implements I_CmsRequestHandler { /** GWT RPC services suffix. */ public static final String HANDLE_GWT = ".gwt"; /** Name of the <code>DefaultWebApplication</code> parameter in the <code>web.xml</code> OpenCms servlet configuration. */ public static final String SERVLET_PARAM_DEFAULT_WEB_APPLICATION = "DefaultWebApplication"; /** Name of the <code>OpenCmsHome</code> parameter in the <code>web.xml</code> OpenCms servlet configuration. */ public static final String SERVLET_PARAM_OPEN_CMS_HOME = "OpenCmsHome"; /** Name of the <code>OpenCmsServlet</code> parameter in the <code>web.xml</code> OpenCms servlet configuration. */ public static final String SERVLET_PARAM_OPEN_CMS_SERVLET = "OpenCmsServlet"; /** Name of the <code>WebApplicationContext</code> parameter in the <code>web.xml</code> OpenCms servlet configuration. */ public static final String SERVLET_PARAM_WEB_APPLICATION_CONTEXT = "WebApplicationContext"; /** Handler prefix. */ private static final String HANDLE_PATH = "/handle"; /** Path to handler "error page" files in the VFS. */ private static final String HANDLE_VFS_PATH = "/system/handler" + HANDLE_PATH; /** Handler "error page" file suffix. */ private static final String HANDLE_VFS_SUFFIX = ".html"; /** Handler implementation names. */ private static final String[] HANDLER_NAMES = { "404" }; /** The log object for this class. */ private static final Log LOG = CmsLog.getLog(OpenCmsServlet.class); /** Serial version UID required for safe serialization. */ private static final long serialVersionUID = 4729951599966070050L; /** * OpenCms servlet main request handling method.<p> * * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) */ @Override public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException, ServletException { // check to OpenCms runlevel int runlevel = OpenCmsCore.getInstance().getRunLevel(); // write OpenCms server identification in the response header res.setHeader(CmsRequestUtil.HEADER_SERVER, OpenCmsCore.getInstance().getSystemInfo().getVersion()); if (runlevel != OpenCms.RUNLEVEL_4_SERVLET_ACCESS) { // not the "normal" servlet runlevel if (runlevel == OpenCms.RUNLEVEL_3_SHELL_ACCESS) { // we have shell runlevel only, upgrade to servlet runlevel (required after setup wizard) init(getServletConfig()); } else { // illegal runlevel, we can't process requests // sending status code 403, indicating the server understood the request but refused to fulfill it res.sendError(HttpServletResponse.SC_FORBIDDEN); // goodbye return; } } String path = OpenCmsCore.getInstance().getPathInfo(req); if (path.startsWith(HANDLE_PATH)) { // this is a request to an OpenCms handler URI invokeHandler(req, res); } else if (path.endsWith(HANDLE_GWT)) { // handle GWT rpc services String serviceName = CmsResource.getName(path); serviceName = serviceName.substring(0, serviceName.length() - HANDLE_GWT.length()); OpenCmsCore.getInstance().invokeGwtService(serviceName, req, res, getServletConfig()); } else { // standard request to a URI in the OpenCms VFS OpenCmsCore.getInstance().showResource(req, res); } } /** * OpenCms servlet POST request handling method, * will just call {@link #doGet(HttpServletRequest, HttpServletResponse)}.<p> * * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse) */ @Override public void doPost(HttpServletRequest req, HttpServletResponse res) throws IOException, ServletException { doGet(req, res); } /** * @see org.opencms.main.I_CmsRequestHandler#getHandlerNames() */ public String[] getHandlerNames() { return HANDLER_NAMES; } /** * @see org.opencms.main.I_CmsRequestHandler#handle(HttpServletRequest, HttpServletResponse, String) */ public void handle(HttpServletRequest req, HttpServletResponse res, String name) throws IOException, ServletException { int errorCode; try { errorCode = Integer.valueOf(name).intValue(); } catch (NumberFormatException nf) { res.sendError(HttpServletResponse.SC_FORBIDDEN); return; } switch (errorCode) { case 404: CmsObject cms = null; CmsStaticExportData exportData = null; try { // this will be set in the root site cms = OpenCms.initCmsObject(OpenCms.getDefaultUsers().getUserExport()); exportData = OpenCms.getStaticExportManager().getExportData(req, cms); } catch (CmsException e) { // unlikely to happen if (LOG.isWarnEnabled()) { LOG.warn(Messages.get().getBundle().key(Messages.LOG_INIT_CMSOBJECT_IN_HANDLER_2, name, OpenCmsCore.getInstance().getPathInfo(req)), e); } } if (exportData != null) { try { // generate a static export request wrapper CmsStaticExportRequest exportReq = new CmsStaticExportRequest(req, exportData); // export the resource and set the response status according to the result res.setStatus(OpenCms.getStaticExportManager().export(exportReq, res, cms, exportData)); } catch (Throwable t) { if (LOG.isWarnEnabled()) { LOG.warn(Messages.get().getBundle().key(Messages.LOG_ERROR_EXPORT_1, exportData), t); } openErrorHandler(req, res, errorCode); } } else { openErrorHandler(req, res, errorCode); } break; default: openErrorHandler(req, res, errorCode); } } /** * @see javax.servlet.Servlet#init(javax.servlet.ServletConfig) */ @Override public synchronized void init(ServletConfig config) throws ServletException { super.init(config); try { // upgrade the runlevel // usually this should have already been done by the context listener // however, after a fresh install / setup this will be done from here OpenCmsCore.getInstance().upgradeRunlevel(config.getServletContext()); // finalize OpenCms initialization OpenCmsCore.getInstance().initServlet(this); } catch (CmsInitException e) { if (Messages.ERR_CRITICAL_INIT_WIZARD_0.equals(e.getMessageContainer().getKey())) { // if wizard is still enabled - allow retry of initialization (required for setup wizard) // this means the servlet init() call must be terminated by an exception if (CmsServletContainerSettings.isServletThrowsException()) { throw new ServletException(e.getMessage()); } else { // this is needed since some servlet containers does not like the servlet to throw exceptions, // like BEA WLS 9.x and Resin LOG.error(Messages.get().getBundle().key(Messages.LOG_ERROR_GENERIC_0), e); } } } catch (Throwable t) { LOG.error(Messages.get().getBundle().key(Messages.LOG_ERROR_GENERIC_0), t); } } /** * Manages requests to internal OpenCms request handlers.<p> * * @param req the current request * @param res the current response * @throws ServletException in case an error occurs * @throws ServletException in case an error occurs * @throws IOException in case an error occurs */ protected void invokeHandler(HttpServletRequest req, HttpServletResponse res) throws IOException, ServletException { String name = OpenCmsCore.getInstance().getPathInfo(req).substring(HANDLE_PATH.length()); I_CmsRequestHandler handler = OpenCmsCore.getInstance().getRequestHandler(name); if (handler != null) { handler.handle(req, res, name); } else { openErrorHandler(req, res, HttpServletResponse.SC_INTERNAL_SERVER_ERROR); } } /** * Displays an error code handler loaded from the OpenCms VFS, * or if such a page does not exist, * displays the default servlet container error code.<p> * * @param req the current request * @param res the current response * @param errorCode the error code to display * @throws IOException if something goes wrong * @throws ServletException if something goes wrong */ protected void openErrorHandler(HttpServletRequest req, HttpServletResponse res, int errorCode) throws IOException, ServletException { String handlerUri = (new StringBuffer(64)).append(HANDLE_VFS_PATH).append(errorCode) .append(HANDLE_VFS_SUFFIX).toString(); CmsObject cms; CmsFile file; try { // create OpenCms context, this will be set in the root site cms = OpenCms.initCmsObject(OpenCms.getDefaultUsers().getUserGuest()); cms.getRequestContext().setUri(handlerUri); // read the error handler file file = cms.readFile(handlerUri, CmsResourceFilter.IGNORE_EXPIRATION); } catch (CmsException e) { // unlikely to happen as the OpenCms "Guest" context can always be initialized CmsMessageContainer container = Messages.get().container(Messages.LOG_INIT_CMSOBJECT_IN_HANDLER_2, new Integer(errorCode), handlerUri); if (LOG.isWarnEnabled()) { LOG.warn(org.opencms.jsp.Messages.getLocalizedMessage(container, req), e); } // however, if it _does_ happen, then we really can't continue here if (!res.isCommitted()) { // since the handler file is not accessible, display the default error page res.sendError(errorCode, e.getLocalizedMessage()); } return; } try { // provide the original error code in a request attribute req.setAttribute(CmsRequestUtil.ATTRIBUTE_ERRORCODE, new Integer(errorCode)); OpenCms.getResourceManager().loadResource(cms, file, req, res); } catch (CmsException e) { // unable to load error page handler VFS resource CmsMessageContainer container = Messages.get().container(Messages.ERR_SHOW_ERR_HANDLER_RESOURCE_2, new Integer(errorCode), handlerUri); throw new ServletException(org.opencms.jsp.Messages.getLocalizedMessage(container, req), e); } } }