/**
* 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.util.HashMap;
import java.util.Map;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.TimeUnit;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.activemq.command.Command;
import org.apache.activemq.command.WireFormatInfo;
import org.apache.activemq.transport.TransportAcceptListener;
import org.apache.activemq.transport.util.TextWireFormat;
import org.apache.activemq.transport.xstream.XStreamWireFormat;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* 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.
*
* @version $Revision$
*/
public class HttpTunnelServlet extends HttpServlet {
private static final long serialVersionUID = -3826714430767484333L;
private static final Log LOG = LogFactory.getLog(HttpTunnelServlet.class);
private TransportAcceptListener listener;
private TextWireFormat wireFormat;
private Map<String, BlockingQueueTransport> clients = new HashMap<String, BlockingQueueTransport>();
private long requestTimeout = 30000L;
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");
}
wireFormat = (TextWireFormat)getServletContext().getAttribute("wireFormat");
if (wireFormat == null) {
wireFormat = createWireFormat();
}
}
protected void doHead(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
createTransportChannel(request, response);
}
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());
// while( packet !=null ) {
wireFormat.marshal(packet, stream);
count++;
// packet = (Command) transportChannel.getQueue().poll(0,
// TimeUnit.MILLISECONDS);
// }
} catch (InterruptedException ignore) {
}
if (count == 0) {
response.setStatus(HttpServletResponse.SC_REQUEST_TIMEOUT);
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// Read the command directly from the reader
Command command = (Command)wireFormat.unmarshalText(request.getReader());
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;
}
transport.doConsume(command);
}
}
private boolean canProcessWireFormatVersion(int version) {
// TODO:
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;
}
synchronized (this) {
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 {
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;
}
synchronized (this) {
BlockingQueueTransport answer = clients.get(clientID);
if (answer != null) {
response.sendError(HttpServletResponse.SC_BAD_REQUEST, "A session for clientID '" + clientID + "' has allready been established");
LOG.warn("A session for clientID '" + clientID + "' has allready been established");
return null;
}
answer = createTransportChannel();
clients.put(clientID, answer);
listener.onAccept(answer);
return answer;
}
}
protected BlockingQueueTransport createTransportChannel() {
return new BlockingQueueTransport(new ArrayBlockingQueue(10));
}
protected TextWireFormat createWireFormat() {
return new XStreamWireFormat();
}
}