@Override
public void handle(HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
// Is this a resumed connect?
LongPollScheduler scheduler =
(LongPollScheduler) request.getAttribute(LongPollScheduler.ATTRIBUTE);
if (scheduler == null) {
// No - process messages
// Remember if we start a batch
boolean batch = false;
// Don't know the session until first message or handshake response.
ServerSessionImpl session = null;
boolean connect = false;
try {
ServerMessage.Mutable[] messages = parseMessages(request);
if (messages == null) return;
PrintWriter writer = null;
for (ServerMessage.Mutable message : messages) {
// Is this a connect?
connect = Channel.META_CONNECT.equals(message.getChannel());
// Get the session from the message
String client_id = message.getClientId();
if (session == null || client_id != null && !client_id.equals(session.getId())) {
session = (ServerSessionImpl) getBayeux().getSession(client_id);
if (_autoBatch && !batch && session != null && !connect && !message.isMeta()) {
// start a batch to group all resulting messages into a single response.
batch = true;
session.startBatch();
}
} else if (!session.isHandshook()) {
batch = false;
session = null;
}
if (connect && session != null) {
// cancel previous scheduler to cancel any prior waiting long poll
// this should also dec the browser ID
session.setScheduler(null);
}
boolean wasConnected = session != null && session.isConnected();
// Forward handling of the message.
// The actual reply is return from the call, but other messages may
// also be queued on the session.
ServerMessage.Mutable reply = bayeuxServerHandle(session, message);
// Do we have a reply ?
if (reply != null) {
if (session == null) {
// This must be a handshake, extract a session from the reply
session = (ServerSessionImpl) getBayeux().getSession(reply.getClientId());
// Get the user agent while we are at it, and add the browser ID cookie
if (session != null) {
String userAgent = request.getHeader("User-Agent");
session.setUserAgent(userAgent);
String browserId = findBrowserId(request);
if (browserId == null) setBrowserId(request, response);
}
} else {
// Special handling for connect
if (connect) {
try {
writer = sendQueue(request, response, session, writer);
// If the writer is non null, we have already started sending a response, so we
// should not suspend
if (writer == null && reply.isSuccessful() && session.isQueueEmpty()) {
// Detect if we have multiple sessions from the same browser
// Note that CORS requests do not send cookies, so we need to handle them
// specially
// CORS requests always have the Origin header
String browserId = findBrowserId(request);
boolean allowSuspendConnect;
if (browserId != null) allowSuspendConnect = incBrowserId(browserId);
else
allowSuspendConnect =
_allowMultiSessionsNoBrowser || request.getHeader("Origin") != null;
if (allowSuspendConnect) {
long timeout = session.calculateTimeout(getTimeout());
// Support old clients that do not send advice:{timeout:0} on the first
// connect
if (timeout > 0 && wasConnected && session.isConnected()) {
// Suspend and wait for messages
Continuation continuation = ContinuationSupport.getContinuation(request);
continuation.setTimeout(timeout);
continuation.suspend(response);
scheduler = new LongPollScheduler(session, continuation, reply, browserId);
session.setScheduler(scheduler);
request.setAttribute(LongPollScheduler.ATTRIBUTE, scheduler);
reply = null;
metaConnectSuspended(request, session, timeout);
} else {
decBrowserId(browserId);
}
} else {
// There are multiple sessions from the same browser
Map<String, Object> advice = reply.getAdvice(true);
if (browserId != null) advice.put("multiple-clients", true);
if (_multiSessionInterval > 0) {
advice.put(Message.RECONNECT_FIELD, Message.RECONNECT_RETRY_VALUE);
advice.put(Message.INTERVAL_FIELD, _multiSessionInterval);
} else {
advice.put(Message.RECONNECT_FIELD, Message.RECONNECT_NONE_VALUE);
reply.setSuccessful(false);
}
session.reAdvise();
}
}
} finally {
if (reply != null && session.isConnected())
session.startIntervalTimeout(getInterval());
}
} else {
if (!isMetaConnectDeliveryOnly() && !session.isMetaConnectDeliveryOnly()) {
writer = sendQueue(request, response, session, writer);
}
}
}
// If the reply has not been otherwise handled, send it
if (reply != null) {
if (connect && session != null && !session.isConnected())
reply.getAdvice(true).put(Message.RECONNECT_FIELD, Message.RECONNECT_NONE_VALUE);
reply = getBayeux().extendReply(session, session, reply);
if (reply != null) {
getBayeux().freeze(reply);
writer = send(request, response, writer, reply);
}
}
}
// Disassociate the reply
message.setAssociated(null);
}
if (writer != null) complete(writer);
} catch (ParseException x) {
handleJSONParseException(request, response, x.getMessage(), x.getCause());
} finally {
// If we started a batch, end it now
if (batch) {
boolean ended = session.endBatch();
// Flush session if not done by the batch, since some browser order <script> requests
if (!ended && isAlwaysFlushingAfterHandle()) session.flush();
} else if (session != null && !connect && isAlwaysFlushingAfterHandle()) {
session.flush();
}
}
} else {
// Get the resumed session
ServerSessionImpl session = scheduler.getSession();
metaConnectResumed(request, session);
PrintWriter writer;
try {
// Send the message queue
writer = sendQueue(request, response, session, null);
} finally {
// We need to start the interval timeout before the connect reply
// otherwise we open up a race condition where the client receives
// the connect reply and sends a new connect request before we start
// the interval timeout, which will be wrong.
// We need to put this into a finally block in case sending the queue
// throws an exception (for example because the client is gone), so that
// we start the interval timeout that is important to sweep the session
if (session.isConnected()) session.startIntervalTimeout(getInterval());
}
// Send the connect reply
ServerMessage.Mutable reply = scheduler.getReply();
if (!session.isConnected())
reply.getAdvice(true).put(Message.RECONNECT_FIELD, Message.RECONNECT_NONE_VALUE);
reply = getBayeux().extendReply(session, session, reply);
if (reply != null) {
getBayeux().freeze(reply);
writer = send(request, response, writer, reply);
}
complete(writer);
}
}
