SignalR connection handling on app pool recycle

Question

I'm using SignalR (0.5.3) Hubs for a chat app where each keystroke is sent to the server (saved in the DB), relayed to all clients and a return value (a string token of sorts) is sent back from the server.

It works fine, until the app pool recycles, then it stops relaying the keystrokes to all the clients (because the in-memory server state is lost I suppose) and the server doesn't return back any values as well. At this point, I suppose all requests via SignalR are queued by IIS and then processed once the app pool has been recycled.

My question is how can I handle this scenario so that all clients are aware of the server unavailability/delay due to app pool recycle, notify the user to wait for a while and then resume operation on reconnect?

Answer 1

There's two options.

For 0.5.3 you can detect when the client goes into "reconnecting" or is "disconnected" and notify the user that there is server issues. Keep in mind in most situations the client will not actually know that it is disconnected if the server just goes away.

OR

If you wait for the next release (1.0alpha) we will take care of the bulk of this for you. On lack of a server we will trigger an onConnectionSlow event which will then result in the client shifting into the "reconnect" (if it does not receive any info) state until the server comes back online. The client will also know if the server goes away (we're adding this functionality) for edge cases such as an app pool recycle.

Hope this helps!