Java tutorial
/* * This library is part of OpenCms - * the Open Source Content Management System * * Copyright (c) Alkacon Software GmbH & Co. KG (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, 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 java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import org.apache.commons.logging.Log; /** * Implements a servlet filter for URL rewriting. * It adds the servlet name (typically "/opencms") if not already present, but necessary. */ public class OpenCmsUrlServletFilter implements Filter { /** The static log object for this class. */ static final Log LOG = CmsLog.getLog(OpenCmsUrlServletFilter.class); /** * Name of the init-param of the filter configuration that is used to provide * a pipe separated list of additional prefixes for which the URIs should not be adjusted. */ private static final String INIT_PARAM_ADDITIONAL_EXCLUDEPREFIXES = "additionalExcludePrefixes"; /** A pipe separated list of URI prefixes, for which URIs should not be adjusted, additionally to the default prefixes. */ private String m_additionalExcludePrefixes; /** The servlet context. */ private String m_contextPath; /** Flag, indicating if the filter has been initialized. */ private boolean m_isInitialized; /** * A regex that matches if the requested URI starts with one of the default exclude prefixes * or a prefix listed in the value of the {@link #INIT_PARAM_ADDITIONAL_EXCLUDEPREFIXES} init-param. */ private String m_regex; /** The servlet name, prefixed by "/". */ private String m_servletPath; /** * Creates a regex that matches all URIs starting with one of the <code>defaultExcludePrefixes</code> * or one of the <code>additionalExcludePrefixes</code>. * * @param contextPath The context path that every URI starts with. * @param defaultExcludePrefixes the default exclude prefixes. * @param additionalExcludePrefixes a pipe separated list of URI prefixes for which the URLs * should not be adjusted - additionally to the default exclude prefixes * * @return a regex that matches all URIs starting with one of the <code>defaultExcludePrefixes</code> * or one of the <code>additionalExcludePrefixes</code>. */ static String createRegex(String contextPath, String[] defaultExcludePrefixes, String additionalExcludePrefixes) { StringBuffer regex = new StringBuffer(); regex.append(contextPath); regex.append('('); regex.append(defaultExcludePrefixes[0]); for (int i = 1; i < defaultExcludePrefixes.length; i++) { regex.append('|').append(defaultExcludePrefixes[i]); } if (!((null == additionalExcludePrefixes) || additionalExcludePrefixes.isEmpty())) { regex.append('|').append(additionalExcludePrefixes); } regex.append(')'); regex.append(".*"); return regex.toString(); } /** * @see javax.servlet.Filter#destroy() */ public void destroy() { m_additionalExcludePrefixes = null; } /** * Adjusts the requested URIs by prepending the name of the {@link org.opencms.main.OpenCmsServlet}, * if the request should be handled by that servlet. * * @see javax.servlet.Filter#doFilter(javax.servlet.ServletRequest, javax.servlet.ServletResponse, javax.servlet.FilterChain) */ public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { if (m_isInitialized || tryToInitialize()) { if (request instanceof HttpServletRequest) { HttpServletRequest req = (HttpServletRequest) request; String uri = req.getRequestURI(); if (!uri.matches(m_regex)) { String adjustedUri = uri.replaceFirst(m_contextPath + "/", m_servletPath); req.getRequestDispatcher(adjustedUri).forward(request, response); return; } } } chain.doFilter(request, response); } /** * @see javax.servlet.Filter#init(javax.servlet.FilterConfig) */ public void init(FilterConfig filterConfig) { m_additionalExcludePrefixes = filterConfig.getInitParameter(INIT_PARAM_ADDITIONAL_EXCLUDEPREFIXES); } /** * Checks if OpenCms has reached run level 4 and if so, it initializes the member variables. * In particular {@link #m_regex}, {@link #m_contextPath} and {@link OpenCmsUrlServletFilter#m_servletPath} are initialized and sets {@link #m_isInitialized} to true. * * @return <code>true</code> if initialization was successful, <code>false</code> otherwise. */ boolean tryToInitialize() { if (m_isInitialized) { return true; } if (OpenCms.getRunLevel() == 4) { m_contextPath = OpenCms.getSystemInfo().getContextPath(); m_servletPath = OpenCms.getSystemInfo().getServletPath() + "/"; /** * The URI prefixes, for which the requested URI should not be rewritten, * i.e., the ones that should not be handled by the {@link org.opencms.main.OpenCmsServlet}. */ String[] defaultExcludePrefixes = new String[] { "/" + OpenCms.getStaticExportManager().getExportPathForConfiguration(), "/workplace", "/VAADIN/", m_servletPath, "/resources/", "/webdav", "/cmisatom", "/services" }; StringBuffer regex = new StringBuffer(); regex.append(m_contextPath); regex.append('('); regex.append(defaultExcludePrefixes[0]); for (int i = 1; i < defaultExcludePrefixes.length; i++) { regex.append('|').append(defaultExcludePrefixes[i]); } if (!((null == m_additionalExcludePrefixes) || m_additionalExcludePrefixes.isEmpty())) { regex.append('|').append(m_additionalExcludePrefixes); } regex.append(')'); regex.append(".*"); m_regex = regex.toString(); m_isInitialized = true; return true; } return false; } }