How to know streaming is cancelled by Client in Hub Streaming Methods?

[windperson]

Hi,
According to issue #898, Client can use cancellation token to ask for stopping streaming result from server,
On server-side, how do I know if the client surely send CancelInvocation message to request stopping streaming, so I can really end my Server-side application level task processing?

[analogrelay]

I believe we don't expose this cancellation token to the Hub method. We will stop reading from the Channel you provide, but there isn't really a way to detect that in the Hub method. We can look at fixing this in a future release.

[windperson]

Got it, thx!

[JanEggers]

are you accepting prs for this and if so on which branch?

[analogrelay]

We still need to clear up the design for this. It would be on the release/2.2 branch. @BrennanConroy is investigating this now.

The likely design will be to flow a cancellation token for all invocations (regardless of InvokeAsync/SendAsync/StreamAsChannelAsync) and have it trigger CancelInvocationMessage on the client. Then update the server to flow a CancellationToken in to any hub method that requests one and trigger it when CancelInvocationMessage is signalled.

[JanEggers]

sounds good,

maybe this helps:

https://github.com/JanEggers/SignalR/commit/fb0b5a9faf8ba13f2cd3048093302a9398431857

cant run the tests because im missing the preview bits...

[BrennanConroy]

6ba5e87