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.commons.monitoring.reporting.web;
018
019 import org.apache.commons.monitoring.reporting.web.handler.FilteringEndpoints;
020 import org.apache.commons.monitoring.reporting.web.handler.HomeEndpoint;
021 import org.apache.commons.monitoring.reporting.web.handler.internal.EndpointInfo;
022 import org.apache.commons.monitoring.reporting.web.handler.internal.Invoker;
023 import org.apache.commons.monitoring.reporting.web.plugin.PluginRepository;
024 import org.apache.commons.monitoring.reporting.web.template.MapBuilder;
025 import org.apache.commons.monitoring.reporting.web.template.Templates;
026
027 import javax.servlet.Filter;
028 import javax.servlet.FilterChain;
029 import javax.servlet.FilterConfig;
030 import javax.servlet.ServletException;
031 import javax.servlet.ServletRequest;
032 import javax.servlet.ServletResponse;
033 import javax.servlet.http.HttpServletRequest;
034 import javax.servlet.http.HttpServletResponse;
035 import java.io.ByteArrayInputStream;
036 import java.io.ByteArrayOutputStream;
037 import java.io.IOException;
038 import java.io.InputStream;
039 import java.io.PrintStream;
040 import java.io.PrintWriter;
041 import java.io.StringWriter;
042 import java.lang.reflect.InvocationHandler;
043 import java.lang.reflect.Method;
044 import java.lang.reflect.Proxy;
045 import java.util.HashMap;
046 import java.util.Map;
047 import java.util.regex.Matcher;
048 import java.util.regex.Pattern;
049
050 public class MonitoringController implements Filter {
051 private final Map<String, byte[]> cachedResources = new HashMap<String, byte[]>();
052 private final Map<Pattern, Invoker> invokers = new HashMap<Pattern, Invoker>();
053 private String mapping;
054 private ClassLoader classloader;
055 private Invoker defaultInvoker;
056
057 @Override
058 public void init(final FilterConfig config) throws ServletException {
059 classloader = Thread.currentThread().getContextClassLoader();
060 initMapping(config);
061 initHandlers();
062 Templates.init(config.getServletContext().getContextPath(), mapping);
063 }
064
065 private void initHandlers() {
066 // home page
067 invokers.putAll(EndpointInfo.build(HomeEndpoint.class, null, "").getInvokers());
068 defaultInvoker = invokers.values().iterator().next();
069
070 // filtered to get the right base for pictures
071 invokers.putAll(EndpointInfo.build(FilteringEndpoints.class, null, "").getInvokers());
072
073 // plugins
074 for (final PluginRepository.PluginInfo plugin : PluginRepository.PLUGIN_INFO) {
075 for (final Map.Entry<Pattern, Invoker> invoker : plugin.getInvokers().entrySet()) {
076 invokers.put(invoker.getKey(), invoker.getValue());
077 }
078 }
079 }
080
081 private void initMapping(FilterConfig config) {
082 mapping = config.getInitParameter("monitoring-mapping");
083 if (mapping == null) {
084 mapping = "";
085 } else if (!mapping.startsWith("/")) {
086 mapping = "/" + mapping;
087 }
088 if (mapping.endsWith("/")) {
089 mapping = mapping.substring(0, mapping.length() - 1);
090 }
091 }
092
093 @Override
094 public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain) throws IOException, ServletException {
095 if (!HttpServletRequest.class.isInstance(request)) {
096 chain.doFilter(request, response);
097 return;
098 }
099
100 final HttpServletRequest httpRequest = HttpServletRequest.class.cast(request);
101 final HttpServletResponse httpResponse = HttpServletResponse.class.cast(response);
102
103 String path = httpRequest.getRequestURI().substring(httpRequest.getContextPath().length() + mapping.length());
104 if (!path.startsWith("/")) {
105 path = "/" + path;
106 }
107
108 // find the matching invoker
109 Invoker invoker = defaultInvoker;
110 Matcher matcher = null;
111 for (final Map.Entry<Pattern, Invoker> entry : invokers.entrySet()) {
112 matcher = entry.getKey().matcher(path);
113 if (matcher.matches()) {
114 invoker = entry.getValue();
115 break;
116 }
117 }
118
119 // resource, they are in the classloader and not in the webapp to ease the embedded case
120 if (path.startsWith("/resources/")) {
121 byte[] bytes = cachedResources.get(path);
122 if (bytes == null) {
123 final InputStream is;
124 if (invoker != defaultInvoker) { // resource is filtered so filtering it before caching it
125 final StringWriter writer = new StringWriter();
126 final PrintWriter printWriter = new PrintWriter(writer);
127 invoker.invoke(httpRequest, HttpServletResponse.class.cast(Proxy.newProxyInstance(classloader, new Class<?>[] { HttpServletResponse.class }, new InvocationHandler() {
128 @Override
129 public Object invoke(final Object proxy, final Method method, final Object[] args) throws Throwable {
130 if ("getWriter".equals(method.getName())) {
131 return printWriter;
132 }
133 return method.invoke(httpResponse, args);
134 }
135 })), null);
136 is = new ByteArrayInputStream(writer.toString().getBytes());
137 } else {
138 is = classloader.getResourceAsStream(path.substring(1));
139 }
140
141 if (is != null) {
142 final ByteArrayOutputStream baos = new ByteArrayOutputStream();
143 int i;
144 while ((i = is.read()) != -1) {
145 baos.write(i);
146 }
147
148 bytes = baos.toByteArray();
149 cachedResources.put(path, bytes);
150 }
151 }
152 if (bytes != null) {
153 httpResponse.getOutputStream().write(bytes);
154 return;
155 }
156 }
157
158 // delegate handling to the invoker if request is not a resource
159 if (invoker == null) {
160 error(response, null);
161 } else {
162 try {
163 invoker.invoke(httpRequest, httpResponse, matcher);
164 } catch (final Exception e) {
165 error(response, e);
166 }
167 }
168 }
169
170 private void error(final ServletResponse response, final Exception e) throws IOException {
171 final String exception;
172 if (e != null) {
173 final ByteArrayOutputStream err = new ByteArrayOutputStream();
174 e.printStackTrace(new PrintStream(err));
175 exception = new String(err.toByteArray());
176 } else {
177 exception = "No matcher found";
178 }
179 Templates.htmlRender(response.getWriter(), "error.vm", new MapBuilder<String, Object>().set("exception", exception).build());
180 }
181
182 @Override
183 public void destroy() {
184 invokers.clear();
185 }
186 }