Broadcasting

ctx.BroadcastAction("NewMessage", nil) fans the named action out to every other connection in the session group. Peers receive it as a regular action invocation; their handler reads the shared message log under a mutex and refreshes local state. The broadcast is queued during the action and executes after it returns successfully.

Try: Open this page in a second tab and Join with a different name. Sending in either tab broadcasts to both. The shared log lives on the controller; each tab's Username is per-connection (not persisted) so two tabs in the same browser stay independent — see Reconnection Recovery for the persist case.

Limitation: The shared message log is in-memory and uncapped — production apps would ring-buffer, paginate, or persist to a TTL store. Kept simple here to focus on the broadcast mechanism itself.