How to close a channel when there is no network?

[michalzaq12]

Ably 2.3.2

How do I close a channel when there's no network? (The channel is no longer needed, and the client's presence should also be removed).
I don't see any pattern for gracefully closing a channel in your documentation.

My code currently looks like this:

channel.detach()
   .finally(() => connection.release(<channelName>))

When there is no network:

1. detach() fails with: _ErrorInfo: Connection to server unavailable
2. release() fails with: Can only release a channel in a state where there is no possibility of further updates from the server being received (initialized, detached, or failed); was suspended

Problems:
Once the network returns, the channel will re-attched and presence will be re-entered.

[SimonWoolf]

Hi! I think there's no reason that detach() shouldn't just succeed in this situation. In the latest version of our protocol, if/when it regains connectivity after a period of no network the SDK will explicitly reattach all channels that were attached, so during the period of disconnection it should just change the channel state to instruct it not to do that. (And the server will have removed the presence entry 15s after it detects the connection drop).

I've proposed an sdk spec change accordingly ably/specification#411 , assuming that's accepted we'll get a release out with the behaviour change in the next few days.

[SimonWoolf]

Fixed in release 2.17.0 (#2149). You can now just call detach() and it will do the right thing when the connection is disconnected. Thanks for reporting!