/**
* 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.activemq.transport.http;
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.TimeUnit;
import java.util.zip.GZIPInputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.activemq.Service;
import org.apache.activemq.command.Command;
import org.apache.activemq.command.ConnectionInfo;
import org.apache.activemq.command.WireFormatInfo;
import org.apache.activemq.transport.Transport;
import org.apache.activemq.transport.TransportAcceptListener;
import org.apache.activemq.transport.util.TextWireFormat;
import org.apache.activemq.transport.xstream.XStreamWireFormat;
import org.apache.activemq.util.IOExceptionSupport;
import org.apache.activemq.util.ServiceListener;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A servlet which handles server side HTTP transport, delegating to the
* ActiveMQ broker. This servlet is designed for being embedded inside an
* ActiveMQ Broker using an embedded Jetty or Tomcat instance.
*/
public class HttpTunnelServlet extends HttpServlet {
private static final long serialVersionUID = -3826714430767484333L;
private static final Logger LOG = LoggerFactory.getLogger(HttpTunnelServlet.class);
private TransportAcceptListener listener;
private HttpTransportFactory transportFactory;
private TextWireFormat wireFormat;
private ConcurrentMap<String, BlockingQueueTransport> clients = new ConcurrentHashMap<String, BlockingQueueTransport>();
private final long requestTimeout = 30000L;
private HashMap<String, Object> transportOptions;
@SuppressWarnings("unchecked")
@Override
public void init() throws ServletException {
super.init();
listener = (TransportAcceptListener)getServletContext().getAttribute("acceptListener");
if (listener == null) {
throw new ServletException("No such attribute 'acceptListener' available in the ServletContext");
}
transportFactory = (HttpTransportFactory)getServletContext().getAttribute("transportFactory");
if (transportFactory == null) {
throw new ServletException("No such attribute 'transportFactory' available in the ServletContext");
}
transportOptions = (HashMap<String, Object>)getServletContext().getAttribute("transportOptions");
wireFormat = (TextWireFormat)getServletContext().getAttribute("wireFormat");
if (wireFormat == null) {
wireFormat = createWireFormat();
}
}
@Override
protected void doOptions(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.addHeader("Accepts-Encoding", "gzip");
super.doOptions(request, response);
}
@Override
protected void doHead(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
createTransportChannel(request, response);
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// lets return the next response
Command packet = null;
int count = 0;
try {
BlockingQueueTransport transportChannel = getTransportChannel(request, response);
if (transportChannel == null) {
return;
}
packet = (Command)transportChannel.getQueue().poll(requestTimeout, TimeUnit.MILLISECONDS);
DataOutputStream stream = new DataOutputStream(response.getOutputStream());
wireFormat.marshal(packet, stream);
count++;
} catch (InterruptedException ignore) {
}
if (count == 0) {
response.setStatus(HttpServletResponse.SC_REQUEST_TIMEOUT);
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
InputStream stream = request.getInputStream();
String contentType = request.getContentType();
if (contentType != null && contentType.equals("application/x-gzip")) {
stream = new GZIPInputStream(stream);
}
// Read the command directly from the reader, assuming UTF8 encoding
Command command = (Command) wireFormat.unmarshalText(new InputStreamReader(stream, "UTF-8"));
if (command instanceof WireFormatInfo) {
WireFormatInfo info = (WireFormatInfo) command;
if (!canProcessWireFormatVersion(info.getVersion())) {
response.sendError(HttpServletResponse.SC_NOT_FOUND, "Cannot process wire format of version: "
+ info.getVersion());
}
} else {
BlockingQueueTransport transport = getTransportChannel(request, response);
if (transport == null) {
return;
}
if (command instanceof ConnectionInfo) {
((ConnectionInfo) command).setTransportContext(request.getAttribute("javax.servlet.request.X509Certificate"));
}
transport.doConsume(command);
}
}
private boolean canProcessWireFormatVersion(int version) {
return true;
}
protected String readRequestBody(HttpServletRequest request) throws IOException {
StringBuffer buffer = new StringBuffer();
BufferedReader reader = request.getReader();
while (true) {
String line = reader.readLine();
if (line == null) {
break;
} else {
buffer.append(line);
buffer.append("\n");
}
}
return buffer.toString();
}
protected BlockingQueueTransport getTransportChannel(HttpServletRequest request, HttpServletResponse response) throws IOException {
String clientID = request.getHeader("clientID");
if (clientID == null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No clientID header specified");
LOG.warn("No clientID header specified");
return null;
}
BlockingQueueTransport answer = clients.get(clientID);
if (answer == null) {
LOG.warn("The clientID header specified is invalid. Client sesion has not yet been established for it: " + clientID);
return null;
}
return answer;
}
protected BlockingQueueTransport createTransportChannel(HttpServletRequest request, HttpServletResponse response) throws IOException {
final String clientID = request.getHeader("clientID");
if (clientID == null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No clientID header specified");
LOG.warn("No clientID header specified");
return null;
}
// Optimistically create the client's transport; this transport may be thrown away if the client has already registered.
BlockingQueueTransport answer = createTransportChannel();
// Record the client's transport and ensure that it has not already registered; this is thread-safe and only allows one
// thread to register the client
if (clients.putIfAbsent(clientID, answer) != null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "A session for clientID '" + clientID + "' has already been established");
LOG.warn("A session for clientID '" + clientID + "' has already been established");
return null;
}
// Ensure that the client's transport is cleaned up when no longer
// needed.
answer.addServiceListener(new ServiceListener() {
public void started(Service service) {
// Nothing to do.
}
public void stopped(Service service) {
clients.remove(clientID);
}
});
// Configure the transport with any additional properties or filters. Although the returned transport is not explicitly
// persisted, if it is a filter (e.g., InactivityMonitor) it will be linked to the client's transport as a TransportListener
// and not GC'd until the client's transport is disposed.
Transport transport = answer;
try {
// Preserve the transportOptions for future use by making a copy before applying (they are removed when applied).
HashMap<String, Object> options = new HashMap<String, Object>(transportOptions);
transport = transportFactory.serverConfigure(answer, null, options);
} catch (Exception e) {
throw IOExceptionSupport.create(e);
}
// Wait for the transport to be connected or disposed.
listener.onAccept(transport);
while (!transport.isConnected() && !transport.isDisposed()) {
try {
Thread.sleep(100);
} catch (InterruptedException ignore) {
}
}
// Ensure that the transport was not prematurely disposed.
if (transport.isDisposed()) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "The session for clientID '" + clientID + "' was prematurely disposed");
LOG.warn("The session for clientID '" + clientID + "' was prematurely disposed");
return null;
}
return answer;
}
protected BlockingQueueTransport createTransportChannel() {
return new BlockingQueueTransport(new LinkedBlockingQueue<Object>());
}
protected TextWireFormat createWireFormat() {
return new XStreamWireFormat();
}
}