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From Filip Hanik - Dev Lists <devli...@hanik.com>
Subject Re: WebSocket status
Date Thu, 01 Mar 2012 18:01:46 GMT
On 2/28/2012 11:39 AM, Mark Thomas wrote:
> Thanks for the feedback.
>
> You may also be able to help with some problems I am having getting
> non-blocking behaviour between messages with NIO. I'm not 100% clear
> what is happening yet, but I think it is something like:
> - HTTP GET (with upgrade request arrives
> - Upgrade is processed
> - no ws frame on the wire (yet) so process of handing back to the
> selector starts
> - first ws frame arrives
> - socket is handed back to the selector
> - selector*does not*  trigger indicating there is data to process
> - some delay of a few seconds
> - client sends another ws frame
> - selector triggers
> - both frames are processed
>
> I can force this behaviour 100% of the time with the debugger and it
> looks very similar to the issues we see intermittently with the Comet
> unit tests where two messages are processed at once.
>
> I am wondering if we have a race condition somewhere in the NIO code
> between:
> - determining there is no data to read
> - handling the socket back to the selector
> - new data arriving
> and if it is possible that for a particular sequence of events we can
> end up in the state where there is data to be read but the selector
> doesn't think so.
>
> I would normally assume my non-blocking code is doing something stupid
> (which it may well be anyway) but the similarity to the problem with the
> Comet unit test makes me suspect at least one root cause may be elsewhere.
>
> Any thoughts appreciated.
>
> (Note all of my non-blocking changes are currently sitting on my local
> hard drive. I can provide them if that would help.)
>
> Mark
Alright, now that I'm all squared away with Autobahn and test cases running. Is there a specific
unit test you have to produce this behavior?
That would help me for digging through it.
Filip

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