[Tomcat-users] Connection is closed when CometEvent.close is called during an event

Hello,

I am using a CometProcessor servlet in a long-poll scenario, and recently had
a closer look at the life span of connections that are used for poll requests.

I noticed that connections are closed by Tomcat whenever a poll request
was answered (and closed) directly during processing of the BEGIN event.
In our application this happens for one out of three poll requests approximately
and thus should not be neglected.

I had a look into the source code and found the reason in the
CoyoteAdapter.event method - it sets the 'error' flag to true in this situation.

I modified the code (in 6.0.20 and 6.0.26) so that the error flag is not set.
With that change Tomcat kept the connection open:

...
// Calling the container
connector.getContainer().getPipeline().getFirst().event(request, response, request.getEvent());

if (!error && !response.isClosed() && (request.getAttribute(Globals.EXCEPTION_ATTR) != null)) {
// An unexpected exception occurred while processing the event, so
// error should be called
request.getEvent().setEventType(CometEvent.EventType.ERROR);
request.getEvent().setEventSubType(null);
error = true;
connector.getContainer().getPipeline().getFirst().event(request, response, request.getEvent());
}
if (response.isClosed() || !request.isComet()) {
if (status==SocketStatus.OPEN) {
//CometEvent.close was called during an event.
request.getEvent().setEventType(CometEvent.EventType.END);
request.getEvent().setEventSubType(null);

// don't set the error flag here - otherwise the connection will be closed
// whenever a long poll is answered already during event handling:
// error = true;

connector.getContainer().getPipeline().getFirst().event(request, response, request.getEvent());
}
res.action(ActionCode.ACTION_COMET_END, null);
} else if (!error && read && request.getAvailable()) {
// If this was a read and not all bytes have been read, or if no data
// was read from the connector, then it is an error
request.getEvent().setEventType(CometEvent.EventType.ERROR);
request.getEvent().setEventSubType(CometEvent.EventSubType.IOEXCEPTION);
error = true;
connector.getContainer().getPipeline().getFirst().event(request, response, request.getEvent());
}
return (!error);
...

In my first tests I did not observe any undesired side effects of the change.
However, I did not yet do extensive tests - especially not with a steaming client.

Do you agree that this should be considered a bug and fixed in the next Tomcat
release?


Regards,
Matthias


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