package org.jboss.errai.bus.server.servlet;
import com.google.inject.Singleton;
import com.sun.grizzly.comet.CometContext;
import com.sun.grizzly.comet.CometEngine;
import com.sun.grizzly.comet.CometEvent;
import com.sun.grizzly.comet.handlers.ReflectorCometHandler;
import org.jboss.errai.bus.client.api.Message;
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.mvel2.util.StringAppender;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.nio.CharBuffer;
import java.util.*;
import static org.jboss.errai.bus.server.io.MessageFactory.createCommandMessage;
/**
* The <tt>GrizzlyCometServlet</tt> provides the HTTP-protocol gateway between the server bus and the client buses,
* using Glassfish.
*/
@Singleton
public class GrizzlyCometServlet extends AbstractErraiServlet {
private static CometContext context = null;
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
private static CometContext createCometContext(String id) {
CometEngine cometEngine = CometEngine.getEngine();
CometContext ctx = cometEngine.register(id);
ctx.setExpirationDelay(45 * 1000);
ctx.setBlockingNotification(false);
return ctx;
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
pollForMessages(sessionProvider.getSession(request.getSession(),
request.getHeader(ClientMessageBus.REMOTE_QUEUE_ID_HEADER)), request, response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
final QueueSession session = sessionProvider.getSession(request.getSession(),
request.getHeader(ClientMessageBus.REMOTE_QUEUE_ID_HEADER));
BufferedReader reader = request.getReader();
StringAppender sb = new StringAppender(request.getContentLength());
CharBuffer buffer = CharBuffer.allocate(10);
int read;
while ((read = reader.read(buffer)) > 0) {
buffer.rewind();
for (; read > 0; read--) {
sb.append(buffer.get());
}
buffer.rewind();
}
for (Message msg : createCommandMessage(session, sb.toString())) {
service.store(msg);
}
pollQueue(service.getBus().getQueue(session), request, response);
}
private void pollForMessages(QueueSession session, HttpServletRequest httpServletRequest,
HttpServletResponse httpServletResponse) throws IOException {
try {
final MessageQueue queue = service.getBus().getQueue(session);
if (queue == null) {
sendDisconnectWithReason(httpServletResponse.getOutputStream(),
"There is no queue associated with this session.");
}
synchronized (queue) {
if (context == null)
context = createCometContext(httpServletRequest.getSession().getId());
final ReflectorCometHandler handler = new ReflectorCometHandler(true);
context.addCometHandler(handler);
if (!queue.messagesWaiting()) {
queue.setActivationCallback(new QueueActivationCallback() {
public void activate(MessageQueue queue) {
queue.setActivationCallback(null);
context.resumeCometHandler(handler);
try {
context.notify(null, CometEvent.NOTIFY, handler);
} catch (IOException e) {
// Should never get here
}
}
});
if (!queue.messagesWaiting()) {
context.setExpirationDelay(45 * 1000);
}
} else {
queue.setActivationCallback(null);
}
pollQueue(queue, httpServletRequest, httpServletResponse);
}
}
catch (final Throwable t) {
t.printStackTrace();
httpServletResponse.setHeader("Cache-Control", "no-cache");
httpServletResponse.addHeader("Payload-Size", "1");
httpServletResponse.setContentType("application/json");
OutputStream stream = httpServletResponse.getOutputStream();
stream.write('[');
writeToOutputStream(stream, new MarshalledMessage() {
public String getSubject() {
return "ClientBusErrors";
}
public Object getMessage() {
StringBuilder b = new StringBuilder("{ErrorMessage:\"").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, HttpServletRequest httpServletRequest,
HttpServletResponse httpServletResponse) throws IOException {
queue.heartBeat();
List<MarshalledMessage> messages = queue.poll(false).getMessages();
httpServletResponse.setHeader("Cache-Control", "no-cache");
httpServletResponse.setContentType("application/json");
OutputStream stream = httpServletResponse.getOutputStream();
Iterator<MarshalledMessage> iter = messages.iterator();
stream.write('[');
while (iter.hasNext()) {
writeToOutputStream(stream, iter.next());
if (iter.hasNext()) {
stream.write(',');
}
}
stream.write(']');
stream.flush();
}
}