/*
* Copyright 2012 JBoss, by 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 static org.jboss.errai.bus.server.io.MessageFactory.createCommandMessage;
import static org.slf4j.LoggerFactory.getLogger;
import java.io.IOException;
import javax.servlet.AsyncContext;
import javax.servlet.AsyncEvent;
import javax.servlet.AsyncListener;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.jboss.errai.bus.client.api.QueueSession;
import org.jboss.errai.bus.server.QueueUnavailableException;
import org.jboss.errai.bus.server.api.MessageQueue;
import org.jboss.errai.bus.server.api.QueueActivationCallback;
import org.jboss.errai.bus.server.io.OutputStreamWriteAdapter;
import org.slf4j.Logger;
/**
* An implementation of {@link AbstractErraiServlet} leveraging asynchronous support of Servlet 3.0.
*
* @author Christian Sadilek <csadilek@redhat.com>
* @author Mike Brock
*/
public class StandardAsyncServlet extends AbstractErraiServlet {
private static final Logger log = getLogger(StandardAsyncServlet.class);
private static final long serialVersionUID = 1L;
@Override
protected void doGet(final HttpServletRequest request, final HttpServletResponse response) throws ServletException,
IOException {
final QueueSession session = sessionProvider.createOrGetSession(request.getSession(), getClientId(request));
session.setAttribute("NoSSE", Boolean.TRUE);
final MessageQueue queue = service.getBus().getQueue(session);
if (queue == null) {
switch (getConnectionPhase(request)) {
case CONNECTING:
case DISCONNECTING:
return;
}
sendDisconnectDueToSessionExpiry(response);
return;
}
queue.heartBeat();
final OutputStreamWriteAdapter writer;
final AsyncContext asyncContext = request.startAsync();
asyncContext.setTimeout(60000);
queue.setTimeout(65000);
writer = new OutputStreamWriteAdapter(asyncContext.getResponse().getOutputStream());
asyncContext.addListener(new AsyncListener() {
@Override
public void onComplete(final AsyncEvent event) throws IOException {
synchronized (queue.getActivationLock()) {
queue.setActivationCallback(null);
asyncContext.complete();
}
}
@Override
public void onTimeout(final AsyncEvent event) throws IOException {
onComplete(event);
}
@Override
public void onError(final AsyncEvent event) throws IOException {
queue.setActivationCallback(null);
}
@Override
public void onStartAsync(final AsyncEvent event) throws IOException {
}
});
synchronized (queue.getActivationLock()) {
if (queue.messagesWaiting()) {
queue.poll(writer);
asyncContext.complete();
return;
}
queue.setActivationCallback(new QueueActivationCallback() {
@Override
public void activate(final MessageQueue queue) {
try {
queue.poll(writer);
queue.setActivationCallback(null);
queue.heartBeat();
writer.flush();
}
catch (IOException e) {
log.debug("Closing queue with id: " + queue.getSession().getSessionId() + " due to IOException", e);
}
catch (final Throwable t) {
try {
writeExceptionToOutputStream((HttpServletResponse) asyncContext.getResponse(), t);
}
catch (Throwable t2) {
log.debug("Failed to write exception to dead client", t2);
}
}
finally {
asyncContext.complete();
}
}
});
writer.flush();
}
}
@Override
protected void doPost(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException {
final QueueSession session = sessionProvider.createOrGetSession(request.getSession(), getClientId(request));
session.setAttribute("NoSSE", Boolean.TRUE);
try {
try {
service.store(createCommandMessage(session, request));
}
catch (QueueUnavailableException e) {
sendDisconnectDueToSessionExpiry(response);
return;
}
final MessageQueue queue = service.getBus().getQueue(session);
if (queue != null) {
if (shouldWait(request)) {
doGet(request, response);
}
else {
queue.poll(new OutputStreamWriteAdapter(response.getOutputStream()));
}
}
}
catch (Exception e) {
final String message = e.getMessage();
if (message == null) {
e.printStackTrace();
}
else if (!message.contains("expired")) {
writeExceptionToOutputStream(response, e);
}
}
}
}