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        @Override
056        public void init(final FilterConfig filterConfig) throws ServletException {
057            context = filterConfig.getServletContext();
058            name = filterConfig.getInitParameter(CONTEXT_NAME);
059            URI configLocation = null;
060            String configLocn = filterConfig.getInitParameter(CONFIG_LOCATION);
061            if (configLocn != null) {
062                try {
063                    configLocation = new URI(configLocn);
064                } catch (Exception ex) {
065                    context.log("Unable to convert config location " + configLocn + " to a URI: " + ex.getMessage());
066                }
067            }
068    
069            if (name == null) {
070                throw new UnavailableException("A context-name attribute is required");
071            }
072            if (context.getAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE) == null) {
073                LoggerContext ctx;
074                final LoggerContextFactory factory = LogManager.getFactory();
075                if (factory instanceof Log4jContextFactory) {
076                    final ContextSelector sel = ((Log4jContextFactory) factory).getSelector();
077                    if (sel instanceof NamedContextSelector) {
078                        selector = (NamedContextSelector) sel;
079                        ctx = selector.locateContext(name, configLocation);
080                    } else {
081                        return;
082                    }
083                } else {
084                    return;
085                }
086                context.setAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE, ctx);
087                created = true;
088                context.log("Created context for " + name + " using " + ctx.getClass().getClassLoader());
089            }
090        }
091    
092        @Override
093        public void doFilter(final ServletRequest servletRequest, final ServletResponse servletResponse,
094                             final FilterChain filterChain)
095            throws IOException, ServletException {
096            final LoggerContext ctx = (LoggerContext) context.getAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE);
097            if (ctx != null) {
098                ContextAnchor.THREAD_CONTEXT.set(ctx);
099                try {
100                    filterChain.doFilter(servletRequest, servletResponse);
101                } finally {
102                    ContextAnchor.THREAD_CONTEXT.remove();
103                }
104            } else {
105                filterChain.doFilter(servletRequest, servletResponse);
106            }
107        }
108    
109        @Override
110        public void destroy() {
111            final LoggerContext ctx = (LoggerContext) context.getAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE);
112            if (ctx != null && created) {
113                context.log("Removing context for " + name);
114                context.removeAttribute(Log4jContextListener.LOG4J_CONTEXT_ATTRIBUTE);
115                if (selector != null) {
116                    selector.removeContext(name);
117                }
118                ctx.stop();
119            }
120        }
121    }