/*
* Copyright 2010 JBoss, a divison Red Hat, Inc
*
* Licensed 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.jboss.errai.bus.server.servlet;
import org.jboss.errai.bus.client.framework.ClientMessageBus;
import org.jboss.errai.bus.client.framework.MarshalledMessage;
import org.jboss.errai.bus.server.api.MessageQueue;
import org.jboss.errai.bus.server.api.QueueActivationCallback;
import org.jboss.errai.bus.server.api.QueueSession;
import org.mortbay.jetty.RetryRequest;
import org.mortbay.util.ajax.Continuation;
import org.mortbay.util.ajax.ContinuationSupport;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import static org.jboss.errai.bus.server.io.MessageFactory.createCommandMessage;
/**
* The <tt>JettyContinuationsServlet</tt> provides the HTTP-protocol gateway between the server bus and the client buses,
* using Jetty Continuations.
*/
public class JettyContinuationsServlet extends AbstractErraiServlet {
/**
* Called by the server (via the <tt>service</tt> method) to allow a servlet to handle a GET request by supplying
* a response
*
* @param httpServletRequest - object that contains the request the client has made of the servlet
* @param httpServletResponse - object that contains the response the servlet sends to the client
* @throws IOException - if an input or output error is detected when the servlet handles the GET request
* @throws ServletException - if the request for the GET could not be handled
*/
@Override
protected void doGet(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)
throws ServletException, IOException {
pollForMessages(sessionProvider.getSession(httpServletRequest.getSession(),
httpServletRequest.getHeader(ClientMessageBus.REMOTE_QUEUE_ID_HEADER)),
httpServletRequest, httpServletResponse, true);
}
/**
* Called by the server (via the <code>service</code> method) to allow a servlet to handle a POST request, by
* sending the request
* xxxxxxx
*
* @param httpServletRequest - object that contains the request the client has made of the servlet
* @param httpServletResponse - object that contains the response the servlet sends to the client
* @throws IOException - if an input or output error is detected when the servlet handles the request
* @throws ServletException - if the request for the POST could not be handled
*/
@Override
protected void doPost(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)
throws ServletException, IOException {
final QueueSession session = sessionProvider.getSession(httpServletRequest.getSession(),
httpServletRequest.getHeader(ClientMessageBus.REMOTE_QUEUE_ID_HEADER));
try {
service.store(createCommandMessage(session, httpServletRequest.getInputStream()));
}
catch (Exception e) {
if (!e.getMessage().contains("expired")) {
writeExceptionToOutputStream(httpServletResponse, e);
}
}
}
private void pollForMessages(QueueSession session, HttpServletRequest httpServletRequest,
HttpServletResponse httpServletResponse, boolean wait) throws IOException {
final OutputStream stream = httpServletResponse.getOutputStream();
try {
final MessageQueue queue = service.getBus().getQueue(session);
if (queue == null) {
switch (getConnectionPhase(httpServletRequest)) {
case CONNECTING:
case DISCONNECTING:
return;
}
sendDisconnectDueToSessionExpiry(httpServletResponse.getOutputStream());
return;
}
synchronized (queue.getActivationLock()) {
if (wait) {
final Continuation cont = ContinuationSupport.getContinuation(httpServletRequest, queue);
if (!cont.isResumed() && !queue.messagesWaiting()) {
queue.setActivationCallback(new JettyQueueActivationCallback(cont));
cont.suspend(45 * 1000);
return;
}
}
pollQueue(queue, stream, httpServletResponse);
}
}
catch (RetryRequest r) {
/**
* This *must* be caught and re-thrown to work property with Jetty.
*/
throw r;
}
catch (final Throwable t) {
t.printStackTrace();
httpServletResponse.setHeader("Cache-Control", "no-cache");
httpServletResponse.setHeader("Pragma", "no-cache");
httpServletResponse.setHeader("Expires", "-1");
httpServletResponse.addHeader("Payload-Size", "1");
httpServletResponse.setContentType("application/json");
stream.write('[');
writeToOutputStream(stream, new MarshalledMessage() {
public String getSubject() {
return "ClientBusErrors";
}
public Object getMessage() {
StringBuilder b = new StringBuilder("{Error" +
"Message:\"").append(t.getMessage()).append("\",AdditionalDetails:\"");
for (StackTraceElement e : t.getStackTrace()) {
b.append(e.toString()).append("<br/>");
}
return b.append("\"}").toString();
}
});
stream.write(']');
}
}
private static void pollQueue(MessageQueue queue, OutputStream stream,
HttpServletResponse httpServletResponse) throws IOException {
if (queue == null) return;
queue.heartBeat();
httpServletResponse.setHeader("Cache-Control", "no-cache");
httpServletResponse.setHeader("Pragma", "no-cache");
httpServletResponse.setHeader("Expires", "-1");
httpServletResponse.setContentType("application/json");
queue.poll(false, stream);
}
private static class JettyQueueActivationCallback implements QueueActivationCallback {
private Continuation cont;
private JettyQueueActivationCallback(Continuation cont) {
this.cont = cont;
}
public void activate(MessageQueue queue) {
queue.setActivationCallback(null);
cont.resume();
}
}
}