| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache license, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the license for the specific language governing permissions and |
| * limitations under the license. |
| */ |
| package org.apache.logging.log4j.web; |
| |
| import java.io.IOException; |
| import javax.servlet.Filter; |
| import javax.servlet.FilterChain; |
| import javax.servlet.FilterConfig; |
| import javax.servlet.ServletContext; |
| import javax.servlet.ServletException; |
| import javax.servlet.ServletRequest; |
| import javax.servlet.ServletResponse; |
| |
| import org.apache.logging.log4j.Logger; |
| import org.apache.logging.log4j.status.StatusLogger; |
| |
| /** |
| * This is responsible for the following: |
| * <ul> |
| * <li>Clearing the logger context when the application has finished starting up.</li> |
| * <li>Setting the logger context before processing a request and clearing it after processing a request.</li> |
| * <li>Setting the logger context when the application is starting to shut down.</li> |
| * </ul> |
| * This filter is a once-per-request filter. It is capable of filtering all the different types of requests |
| * (standard, asynchronous, error, etc.) but will not apply processing if the filter matches multiple times on the same |
| * logical request. |
| */ |
| public class Log4jServletFilter implements Filter { |
| |
| private static final Logger LOGGER = StatusLogger.getLogger(); |
| |
| static final String ALREADY_FILTERED_ATTRIBUTE = Log4jServletFilter.class.getName() + ".FILTERED"; |
| |
| private ServletContext servletContext; |
| private Log4jWebLifeCycle initializer; |
| |
| @Override |
| public void init(final FilterConfig filterConfig) throws ServletException { |
| this.servletContext = filterConfig.getServletContext(); |
| LOGGER.debug("Log4jServletFilter initialized."); |
| |
| this.initializer = WebLoggerContextUtils.getWebLifeCycle(this.servletContext); |
| this.initializer.clearLoggerContext(); // the application is mostly finished starting up now |
| } |
| |
| @Override |
| public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain) |
| throws IOException, ServletException { |
| if (request.getAttribute(ALREADY_FILTERED_ATTRIBUTE) != null) { |
| chain.doFilter(request, response); |
| } else { |
| request.setAttribute(ALREADY_FILTERED_ATTRIBUTE, Boolean.TRUE); |
| |
| try { |
| this.initializer.setLoggerContext(); |
| |
| chain.doFilter(request, response); |
| } finally { |
| this.initializer.clearLoggerContext(); |
| } |
| } |
| } |
| |
| @Override |
| public void destroy() { |
| if (this.servletContext == null || this.initializer == null) { |
| throw new IllegalStateException("Filter destroyed before it was initialized."); |
| } |
| LOGGER.debug("Log4jServletFilter destroyed."); |
| |
| this.initializer.setLoggerContext(); // the application is just now starting to shut down |
| } |
| } |