001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements. See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache license, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License. You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the license for the specific language governing permissions and
015     * limitations under the license.
016     */
017    package org.apache.logging.log4j.core.web;
018    
019    import org.apache.logging.log4j.LogManager;
020    import org.apache.logging.log4j.core.impl.ContextAnchor;
021    import org.apache.logging.log4j.core.impl.Log4jContextFactory;
022    import org.apache.logging.log4j.core.selector.ContextSelector;
023    import org.apache.logging.log4j.core.LoggerContext;
024    import org.apache.logging.log4j.core.selector.NamedContextSelector;
025    import org.apache.logging.log4j.spi.LoggerContextFactory;
026    
027    import javax.servlet.Filter;
028    import javax.servlet.FilterChain;
029    import javax.servlet.FilterConfig;
030    import javax.servlet.ServletContext;
031    import javax.servlet.ServletException;
032    import javax.servlet.ServletRequest;
033    import javax.servlet.ServletResponse;
034    import javax.servlet.UnavailableException;
035    import java.io.IOException;
036    import java.net.URI;
037    
038    /**
039     * ServletFilter than may be used to set up a LoggerContext for each web application.
040     */
041    public class JNDIContextFilter implements Filter {
042        /**
043         * The Filter init parameter that defines the name of the LoggerContext.
044         */
045        public static final String CONTEXT_NAME = "context-name";
046        /**
047         * The Filter init parameter that defines the configuration location for the LoggerContext.
048         */
049        public static final String CONFIG_LOCATION = "config-location";
050        private ServletContext context;
051        private boolean created = false;
052        private String name;
053        private NamedContextSelector selector = null;
054    
055        public void init(final FilterConfig filterConfig) throws ServletException {
056            context = filterConfig.getServletContext();
057            name = filterConfig.getInitParameter(CONTEXT_NAME);
058            URI configLocation = null;
059            String configLocn = filterConfig.getInitParameter(CONFIG_LOCATION);
060            if (configLocn != null) {
061                try {
062                    configLocation = new URI(configLocn);
063                } catch (Exception ex) {
064                    context.log("Unable to convert config location " + configLocn + " to a URI: " + ex.getMessage());
065                }
066            }
067    
068            if (name == null) {
069                throw new UnavailableException("A context-name attribute is required");
070            }
071            if (context.getAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE) == null) {
072                LoggerContext ctx;
073                final LoggerContextFactory factory = LogManager.getFactory();
074                if (factory instanceof Log4jContextFactory) {
075                    final ContextSelector sel = ((Log4jContextFactory) factory).getSelector();
076                    if (sel instanceof NamedContextSelector) {
077                        selector = (NamedContextSelector) sel;
078                        ctx = selector.locateContext(name, configLocation);
079                    } else {
080                        return;
081                    }
082                } else {
083                    return;
084                }
085                context.setAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE, ctx);
086                created = true;
087                context.log("Created context for " + name + " using " + ctx.getClass().getClassLoader());
088            }
089        }
090    
091        public void doFilter(final ServletRequest servletRequest, final ServletResponse servletResponse,
092                             final FilterChain filterChain)
093            throws IOException, ServletException {
094            final LoggerContext ctx = (LoggerContext) context.getAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE);
095            if (ctx != null) {
096                ContextAnchor.THREAD_CONTEXT.set(ctx);
097                try {
098                    filterChain.doFilter(servletRequest, servletResponse);
099                } finally {
100                    ContextAnchor.THREAD_CONTEXT.remove();
101                }
102            } else {
103                filterChain.doFilter(servletRequest, servletResponse);
104            }
105        }
106    
107        public void destroy() {
108            final LoggerContext ctx = (LoggerContext) context.getAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE);
109            if (ctx != null && created) {
110                context.log("Removing context for " + name);
111                context.removeAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE);
112                if (selector != null) {
113                    selector.removeContext(name);
114                }
115                ctx.stop();
116            }
117        }
118    }