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.web.appender; 018 019 import org.apache.logging.log4j.LogManager; 020 import org.apache.logging.log4j.core.Filter; 021 import org.apache.logging.log4j.core.Layout; 022 import org.apache.logging.log4j.core.LogEvent; 023 import org.apache.logging.log4j.core.LoggerContext; 024 import org.apache.logging.log4j.core.appender.AbstractAppender; 025 import org.apache.logging.log4j.core.config.plugins.Plugin; 026 import org.apache.logging.log4j.core.config.plugins.PluginAttribute; 027 import org.apache.logging.log4j.core.config.plugins.PluginConfiguration; 028 import org.apache.logging.log4j.core.config.plugins.PluginElement; 029 import org.apache.logging.log4j.core.config.plugins.PluginFactory; 030 import org.apache.logging.log4j.core.impl.ContextAnchor; 031 import org.apache.logging.log4j.core.layout.AbstractStringLayout; 032 import org.apache.logging.log4j.core.layout.PatternLayout; 033 import org.apache.logging.log4j.core.util.Booleans; 034 035 import javax.servlet.ServletContext; 036 import java.io.Serializable; 037 038 /** 039 * Logs using the ServletContext's log method 040 */ 041 @Plugin(name = "Servlet", category = "Core", elementType = "appender", printObject = true) 042 public class ServletAppender extends AbstractAppender { 043 private final ServletContext servletContext; 044 045 private ServletAppender(final String name, final AbstractStringLayout layout, final Filter filter, 046 final ServletContext servletContext, final boolean ignoreExceptions) { 047 super(name, filter, layout, ignoreExceptions); 048 this.servletContext = servletContext; 049 } 050 051 @Override 052 public void append(final LogEvent event) { 053 servletContext.log(((AbstractStringLayout) getLayout()).toSerializable(event)); 054 } 055 056 /** 057 * Create a Console Appender. 058 * @param layout The layout to use (required). 059 * @param filter The Filter or null. 060 * @param name The name of the Appender (required). 061 * @param ignore If {@code "true"} (default) exceptions encountered when appending events are logged; otherwise 062 * they are propagated to the caller. 063 * @return The ServletAppender. 064 */ 065 @PluginFactory 066 public static ServletAppender createAppender( 067 @PluginElement("Layout") Layout<? extends Serializable> layout, 068 @PluginElement("Filter") final Filter filter, 069 @PluginAttribute("name") final String name, 070 @PluginAttribute(value = "ignoreExceptions", defaultBoolean = true) final String ignore) { 071 if (name == null) { 072 LOGGER.error("No name provided for ConsoleAppender"); 073 return null; 074 } 075 final ServletContext servletContext = getServletContext(); 076 if (servletContext == null) { 077 LOGGER.error("No servlet context is available"); 078 return null; 079 } 080 if (layout == null) { 081 layout = PatternLayout.createDefaultLayout(); 082 } else if (!(layout instanceof AbstractStringLayout)) { 083 LOGGER.error("Layout must be a StringLayout to log to ServletContext"); 084 return null; 085 } 086 final boolean ignoreExceptions = Booleans.parseBoolean(ignore, true); 087 return new ServletAppender(name, (AbstractStringLayout) layout, filter, servletContext, ignoreExceptions); 088 } 089 090 private static ServletContext getServletContext() { 091 LoggerContext lc = ContextAnchor.THREAD_CONTEXT.get(); 092 if (lc == null) { 093 lc = (LoggerContext) LogManager.getContext(false); 094 } 095 if (lc != null) { 096 final Object obj = lc.getExternalContext(); 097 return obj != null && obj instanceof ServletContext ? (ServletContext) obj : null; 098 } 099 return null; 100 } 101 }