Ben,
> On 18 Feb 2018, at 15:29, Ben Coman wrote:
>
> The websockets guide here
> https://ci.inria.fr/pharo-contribution/job/EnterprisePharoBook/lastSuccessfulBuild/artifact/book-result/WebSockets/WebSockets.html
>
> says "Reading and sending are completely separate and independent" and the
> class comment says its "full-duplex". From these I presume sending and
> receiving are okay to occur in separate threads, but this is not explicitly
> stated, so can someone confirm this?
The reading and the writing over a web socket connection are independent, so
yes that would be OK. Of course, they would both share the same network stream
(just use each half independently) - that normally works fine.
> So for the given example
> | webSocket |
> webSocket := ZnWebSocket to: 'ws://echo.websocket.org'.
> [ webSocket
>sendMessage: 'Pharo Smalltalk using Zinc WebSockets !';
>readMessage ] ensure: [ webSocket close ].
>
> re-implementing as follows seems to work...
> webSocket := ZnWebSocket to: 'ws://echo.websocket.org'.
> [ webSocket runWith: [ :msg | Transcript crShow: msg ] ] forkAt: 35.
> webSocket sendMessage: 'Pharo Smalltalk using Zinc WebSockets !'.
> webSocket sendMessage: 'Another multi-thread echo'.
> webSocket close
>
> but that could just be by luck, so I ask.
No, that should work.
> btw, if I don't send the #close in the last line, after ~30 seconds I get an
> error
> ConnectionClosed: Cannot write data
> which seems reasonable that the other end timed out and closed the connection,
>
> but when I send the #close, after ~30 seconds I get an error...
>PrimitiveFailed: primitive #primSocketReceiveDataAvailable: in Socket
> failed
> which is unfriendly. What is the best way to neatly stop trying to receive
> data when we explicitly close the websocket?
Of course that fails, you fork a reading loop containing #runWith: which has to
end/stop somehow, the lazy way is by allowing an error to bubble up.
> cheers -ben
>
>
> P.S. I wonder if when a ZnWebSocket is closed, it might be worthwhile
> to do "role:=#closed" to provide some visibility of its state in its
> GTInspector [Raw] tab..
Maybe, but there is #isConnected and the Socket inspector 'Socket Info' shows
lots of details, you can rely on that.
Sven
