001/*
002 * This library is part of OpenCms -
003 * the Open Source Content Management System
004 *
005 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
006 *
007 * This library is free software; you can redistribute it and/or
008 * modify it under the terms of the GNU Lesser General Public
009 * License as published by the Free Software Foundation; either
010 * version 2.1 of the License, or (at your option) any later version.
011 *
012 * This library is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015 * Lesser General Public License for more details.
016 *
017 * For further information about Alkacon Software GmbH & Co. KG, please see the
018 * company website: http://www.alkacon.com
019 *
020 * For further information about OpenCms, please see the
021 * project website: http://www.opencms.org
022 *
023 * You should have received a copy of the GNU Lesser General Public
024 * License along with this library; if not, write to the Free Software
025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
026 */
027
028package org.opencms.main;
029
030import org.opencms.jsp.util.CmsJspStatusBean;
031import org.opencms.util.CmsStringUtil;
032
033import java.io.IOException;
034import java.util.Arrays;
035import java.util.HashSet;
036import java.util.Set;
037
038import javax.servlet.ServletConfig;
039import javax.servlet.ServletException;
040import javax.servlet.http.HttpServletRequest;
041import javax.servlet.http.HttpServletResponse;
042
043/**
044 * This the error handler servlet of the OpenCms system.<p>
045 *
046 * This almost 1:1 extends the "standard" {@link org.opencms.main.OpenCmsServlet}.
047 * By default, all errors are handled by this servlet, which is controlled by the
048 * setting in the shipped <code>web.xml</code>.<p>
049 *
050 * This servlet is required because certain servlet containers (eg. BEA Weblogic)
051 * can not handler the error with the same servlet that produced the error.<p>
052 *
053 * @since 6.2.0
054 *
055 * @see org.opencms.main.OpenCmsServlet
056 * @see org.opencms.staticexport.CmsStaticExportManager
057 */
058public class OpenCmsServletErrorHandler extends OpenCmsServlet {
059
060    /** Serial version UID required for safe serialization. */
061    private static final long serialVersionUID = 5316004893684482816L;
062
063    /** HTTP methods for which we want normal handling (rather than just setting the error code) .*/
064    private static Set<String> defaultMethods = new HashSet<>(Arrays.asList("GET", "HEAD", "POST"));
065
066    /**
067     * OpenCms servlet main request handling method.<p>
068     *
069     * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
070     */
071    @Override
072    public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException, ServletException {
073
074        // check the error status
075        Integer errorStatus = (Integer)req.getAttribute(CmsJspStatusBean.ERROR_STATUS_CODE);
076        if (errorStatus != null) {
077            // only use super method if an error status code is set
078            if (OpenCmsCore.getInstance().getRunLevel() > OpenCms.RUNLEVEL_3_SHELL_ACCESS) {
079                // use super method if servlet run level is available
080                super.doGet(req, res);
081            } else {
082                // otherwise display a simple error page
083                String errorMessage = (String)req.getAttribute(CmsJspStatusBean.ERROR_MESSAGE);
084                if (CmsStringUtil.isEmptyOrWhitespaceOnly(errorMessage)) {
085                    errorMessage = "";
086                }
087                String output = "<html><body>"
088                    + CmsStringUtil.escapeHtml(
089                        Messages.get().getBundle().key(
090                            Messages.ERR_OPENCMS_NOT_INITIALIZED_2,
091                            errorStatus,
092                            errorMessage))
093                    + "</body></html>";
094                res.setStatus(errorStatus.intValue());
095                res.getWriter().println(output);
096            }
097        } else {
098            // no status code set, this is an invalid request
099            res.sendError(HttpServletResponse.SC_FORBIDDEN);
100        }
101    }
102
103    /**
104     * @see javax.servlet.Servlet#init(javax.servlet.ServletConfig)
105     */
106    @Override
107    public synchronized void init(ServletConfig config) {
108
109        // override super class to avoid default initialization
110    }
111
112    /**
113     * @see javax.servlet.http.HttpServlet#service(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
114     */
115    @Override
116    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
117
118        // the service() method of HttpServlet sets a status code of 405 for unimplemented / unsupported methods,
119        // which is a problem for servlets using non-standard methods like the WebDAV servlet (in the case of WebDAV,
120        // it might break clients which rely on status 404 to be returned for PROPFIND requests to nonexistent resources).
121        // So we just set the HTTP response status to the original status for all methods except GET/POST.
122
123        if (defaultMethods.contains(req.getMethod())) {
124            super.service(req, resp);
125        } else {
126            Integer errorStatus = (Integer)req.getAttribute(CmsJspStatusBean.ERROR_STATUS_CODE);
127            if (errorStatus != null) {
128                resp.setStatus(errorStatus.intValue());
129            }
130        }
131
132    }
133
134}