Source code

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 */
017package org.apache.activemq.transport.http;
018
019import java.io.BufferedReader;
020import java.io.DataOutputStream;
021import java.io.IOException;
022import java.io.InputStream;
023import java.io.InputStreamReader;
024import java.util.HashMap;
025import java.util.concurrent.ConcurrentHashMap;
026import java.util.concurrent.ConcurrentMap;
027import java.util.concurrent.LinkedBlockingQueue;
028import java.util.concurrent.TimeUnit;
029import java.util.zip.GZIPInputStream;
030import javax.servlet.ServletException;
031import javax.servlet.http.HttpServlet;
032import javax.servlet.http.HttpServletRequest;
033import javax.servlet.http.HttpServletResponse;
034
035import org.apache.activemq.Service;
036import org.apache.activemq.command.Command;
037import org.apache.activemq.command.ConnectionInfo;
038import org.apache.activemq.command.WireFormatInfo;
039import org.apache.activemq.transport.Transport;
040import org.apache.activemq.transport.TransportAcceptListener;
041import org.apache.activemq.transport.util.TextWireFormat;
042import org.apache.activemq.transport.xstream.XStreamWireFormat;
043import org.apache.activemq.util.IOExceptionSupport;
044import org.apache.activemq.util.ServiceListener;
045import org.slf4j.Logger;
046import org.slf4j.LoggerFactory;
047
048/**
049 * A servlet which handles server side HTTP transport, delegating to the
050 * ActiveMQ broker. This servlet is designed for being embedded inside an
051 * ActiveMQ Broker using an embedded Jetty or Tomcat instance.
052 */
053public class HttpTunnelServlet extends HttpServlet {
054    private static final long serialVersionUID = -3826714430767484333L;
055    private static final Logger LOG = LoggerFactory.getLogger(HttpTunnelServlet.class);
056
057    private TransportAcceptListener listener;
058    private HttpTransportFactory transportFactory;
059    private TextWireFormat wireFormat;
060    private ConcurrentMap<String, BlockingQueueTransport> clients = new ConcurrentHashMap<String, BlockingQueueTransport>();
061    private final long requestTimeout = 30000L;
062    private HashMap<String, Object> transportOptions;
063    private HashMap<String, Object> wireFormatOptions;
064
065    @SuppressWarnings("unchecked")
066    @Override
067    public void init() throws ServletException {
068        super.init();
069        listener = (TransportAcceptListener)getServletContext().getAttribute("acceptListener");
070        if (listener == null) {
071            throw new ServletException("No such attribute 'acceptListener' available in the ServletContext");
072        }
073        transportFactory = (HttpTransportFactory)getServletContext().getAttribute("transportFactory");
074        if (transportFactory == null) {
075            throw new ServletException("No such attribute 'transportFactory' available in the ServletContext");
076        }
077        transportOptions = (HashMap<String, Object>)getServletContext().getAttribute("transportOptions");
078        wireFormatOptions = (HashMap<String, Object>)getServletContext().getAttribute("wireFormatOptions");
079        wireFormat = (TextWireFormat)getServletContext().getAttribute("wireFormat");
080        if (wireFormat == null) {
081            wireFormat = createWireFormat();
082        }
083    }
084
085    @Override
086    protected void doOptions(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
087        response.addHeader("Accepts-Encoding", "gzip");
088        super.doOptions(request, response);
089    }
090
091    @Override
092    protected void doHead(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
093        createTransportChannel(request, response);
094    }
095
096    @Override
097    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
098        // lets return the next response
099        Command packet = null;
100        int count = 0;
101        try {
102            BlockingQueueTransport transportChannel = getTransportChannel(request, response);
103            if (transportChannel == null) {
104                return;
105            }
106
107            packet = (Command)transportChannel.getQueue().poll(requestTimeout, TimeUnit.MILLISECONDS);
108
109            DataOutputStream stream = new DataOutputStream(response.getOutputStream());
110            wireFormat.marshal(packet, stream);
111            count++;
112        } catch (InterruptedException ignore) {
113        }
114
115        if (count == 0) {
116            response.setStatus(HttpServletResponse.SC_REQUEST_TIMEOUT);
117        }
118    }
119
120    @Override
121    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
122
123        if (wireFormatOptions.get("maxFrameSize") != null && request.getContentLength() > Integer.parseInt(wireFormatOptions.get("maxFrameSize").toString())) {
124            throw new ServletException("maxFrameSize exceeded");
125        }
126
127        InputStream stream = request.getInputStream();
128        String contentType = request.getContentType();
129        if (contentType != null && contentType.equals("application/x-gzip")) {
130            stream = new GZIPInputStream(stream);
131        }
132
133        // Read the command directly from the reader, assuming UTF8 encoding
134        Command command = (Command) wireFormat.unmarshalText(new InputStreamReader(stream, "UTF-8"));
135
136        if (command instanceof WireFormatInfo) {
137            WireFormatInfo info = (WireFormatInfo) command;
138            if (!canProcessWireFormatVersion(info.getVersion())) {
139                response.sendError(HttpServletResponse.SC_NOT_FOUND, "Cannot process wire format of version: "
140                        + info.getVersion());
141            }
142
143        } else {
144
145            BlockingQueueTransport transport = getTransportChannel(request, response);
146            if (transport == null) {
147                return;
148            }
149
150            if (command instanceof ConnectionInfo) {
151                ((ConnectionInfo) command).setTransportContext(request.getAttribute("javax.servlet.request.X509Certificate"));
152            }
153            transport.doConsume(command);
154        }
155    }
156
157    private boolean canProcessWireFormatVersion(int version) {
158        return true;
159    }
160
161    protected String readRequestBody(HttpServletRequest request) throws IOException {
162        StringBuffer buffer = new StringBuffer();
163        BufferedReader reader = request.getReader();
164        while (true) {
165            String line = reader.readLine();
166            if (line == null) {
167                break;
168            } else {
169                buffer.append(line);
170                buffer.append("\n");
171            }
172        }
173        return buffer.toString();
174    }
175
176    protected BlockingQueueTransport getTransportChannel(HttpServletRequest request, HttpServletResponse response) throws IOException {
177        String clientID = request.getHeader("clientID");
178        if (clientID == null) {
179            response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No clientID header specified");
180            LOG.warn("No clientID header specified");
181            return null;
182        }
183        BlockingQueueTransport answer = clients.get(clientID);
184        if (answer == null) {
185            LOG.warn("The clientID header specified is invalid. Client sesion has not yet been established for it: " + clientID);
186            return null;
187        }
188        return answer;
189    }
190
191    protected BlockingQueueTransport createTransportChannel(HttpServletRequest request, HttpServletResponse response) throws IOException {
192        final String clientID = request.getHeader("clientID");
193
194        if (clientID == null) {
195            response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No clientID header specified");
196            LOG.warn("No clientID header specified");
197            return null;
198        }
199
200        // Optimistically create the client's transport; this transport may be thrown away if the client has already registered.
201        BlockingQueueTransport answer = createTransportChannel();
202
203        // Record the client's transport and ensure that it has not already registered; this is thread-safe and only allows one
204        // thread to register the client
205        if (clients.putIfAbsent(clientID, answer) != null) {
206            response.sendError(HttpServletResponse.SC_BAD_REQUEST, "A session for the given clientID has already been established");
207            LOG.warn("A session for clientID '" + clientID + "' has already been established");
208            return null;
209        }
210
211        // Ensure that the client's transport is cleaned up when no longer
212        // needed.
213        answer.addServiceListener(new ServiceListener() {
214            public void started(Service service) {
215                // Nothing to do.
216            }
217
218            public void stopped(Service service) {
219                clients.remove(clientID);
220            }
221        });
222
223        // Configure the transport with any additional properties or filters.  Although the returned transport is not explicitly
224        // persisted, if it is a filter (e.g., InactivityMonitor) it will be linked to the client's transport as a TransportListener
225        // and not GC'd until the client's transport is disposed.
226        Transport transport = answer;
227        try {
228            // Preserve the transportOptions for future use by making a copy before applying (they are removed when applied).
229            HashMap<String, Object> options = new HashMap<String, Object>(transportOptions);
230            transport = transportFactory.serverConfigure(answer, null, options);
231        } catch (Exception e) {
232            throw IOExceptionSupport.create(e);
233        }
234
235        // Wait for the transport to be connected or disposed.
236        listener.onAccept(transport);
237        while (!transport.isConnected() && !transport.isDisposed()) {
238            try {
239                Thread.sleep(100);
240            } catch (InterruptedException ignore) {
241            }
242        }
243
244        // Ensure that the transport was not prematurely disposed.
245        if (transport.isDisposed()) {
246            response.sendError(HttpServletResponse.SC_BAD_REQUEST, "The session for the given clientID was prematurely disposed");
247            LOG.warn("The session for clientID '" + clientID + "' was prematurely disposed");
248            return null;
249        }
250
251        return answer;
252    }
253
254    protected BlockingQueueTransport createTransportChannel() {
255       return new BlockingQueueTransport(new LinkedBlockingQueue<Object>());
256    }
257
258    protected TextWireFormat createWireFormat() {
259        return new XStreamWireFormat();
260    }
261}