Disconnect an existing client connection when a second login is detected

[SteveTsai]

I would like to kick out an online user from nakama while 2nd login. The way I do is send a nk.NotificationSend() to client and then nk.SessionDisconnect(). but I tested, the client may receive ISocket.Closed first without receiving any notification. Is there any way that “flush” all notifications or rpc call to make sure the network packages got sent before the websocket is closed? or anyone could suggest good way to kick user with error message to game client.

[mofirouz]

There is no way for the server to queue things and wait for them before disconnecting the socket as various operations of the server runs concurrently.

One alternative is to introduce a delay between sending notification and closing the socket on the Runtime code. This should help ensure message delivery to the client.

Also I suggest taking a look at this forum post:

Preventing users from having multiple sessions

Thanks @hdjay0129. That’s a great answer. I’ll add more detail for @naskha01 and anyone who stumbles across this question. When a socket connection is opened with a session to Nakama the session is implicitly placed onto the notification stream. This allows the user to receive in-app notifications to that session. With the low level streams feature in Nakama you can take advantage of this info to check whether a session for the user already exists with a stream count of that notification stream…

[SteveTsai]

Thank you, @mofirouz.
That’s what I have in mind now. a delay call SessionDisconnect().