package org.jboss.errai.bus.server.servlet;
import com.google.inject.Singleton;
import org.jboss.errai.bus.client.framework.MarshalledMessage;
import org.jboss.errai.bus.client.api.Message;
import org.jboss.errai.bus.server.MessageQueue;
import org.jboss.errai.bus.server.QueueActivationCallback;
import org.mortbay.jetty.RetryRequest;
import org.mortbay.util.ajax.Continuation;
import org.mortbay.util.ajax.ContinuationSupport;
import org.mvel2.util.StringAppender;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.CharBuffer;
import java.util.Iterator;
import java.util.List;
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.
*/
@Singleton
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(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
*
* @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 {
BufferedReader reader = httpServletRequest.getReader();
StringAppender sb = new StringAppender(httpServletRequest.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(sessionProvider.getSession(httpServletRequest.getSession()), sb.toString())) {
service.store(msg);
}
pollQueue(service.getBus().getQueue(httpServletRequest.getSession().getId()), httpServletRequest, httpServletResponse);
}
private void pollForMessages(HttpServletRequest httpServletRequest,
HttpServletResponse httpServletResponse, boolean wait) throws IOException {
try {
final MessageQueue queue = service.getBus().getQueue(httpServletRequest.getSession().getId());
if (queue == null) {
sendDisconnectWithReason(httpServletResponse.getOutputStream(),
"There is no queue associated with this session.");
}
synchronized (queue) {
if (wait) {
final Continuation cont = ContinuationSupport.getContinuation(httpServletRequest, queue);
if (!queue.messagesWaiting()) {
queue.setActivationCallback(new QueueActivationCallback() {
public void activate(MessageQueue queue) {
queue.setActivationCallback(null);
cont.resume();
}
});
if (!queue.messagesWaiting()) {
cont.suspend(45 * 1000);
}
} else {
queue.setActivationCallback(null);
}
}
pollQueue(queue, httpServletRequest, 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.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.addHeader("Payload-Size", String.valueOf(messages.size()));
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();
// stream.close();
}
}