Maximum number of simultaneously open connections across all routes. 0 (the default) means unlimited. At the limit, further upgrade requests are refused with HTTP 503 before any socket is created.

Interval in milliseconds at which WebSocketPluginOptions.heartbeatPayload is sent to every open connection. 0 (the default) disables the heartbeat entirely and creates no timer.

The heartbeat is an application-level message, not an RFC 6455 ping frame: the web WebSocket API exposed by Deno and Cloudflare Workers has no ping(), so a protocol ping would silently no-op on half the supported runtimes.

The text frame sent on each heartbeat tick. Defaults to 'ping'. Read only when WebSocketPluginOptions.heartbeatMs is above 0.

Milliseconds of inbound silence after which a connection is closed with code 1001. 0 (the default) disables idle closing.

Requires WebSocketPluginOptions.heartbeatMs above 0, since the heartbeat tick is what performs the sweep. Configuring an idle timeout without a heartbeat throws at registration rather than silently doing nothing.

Maximum size in bytes of a single inbound frame. 0 (the default) means unlimited. A larger frame closes the connection with code 1009 (message too big) and is never delivered to onMessage.

Whether to log one info line at registration when no realtime backplane is registered, stating that rooms broadcast in-process only. Defaults to true.

Set false to silence it — appropriate when you have decided single-replica fan-out is correct for this deployment and do not want the line on every startup. It suppresses only the message: room delivery is unaffected either way, and the notice never appears once a backplane is registered.

Routes registered declaratively, as an alternative to calling service.route(...) imperatively after start(). Each entry — instance or RegistryFactory — produces one route() call, so a route can be declared where the plugin is composed instead of after the application has started.

Instance entries register during the plugin's register() phase, identical to the imperative timing. Factory entries are resolved in the onInit phase — the first at which the registry holds every capability — so a factory can build its handlers from a resolved capability. A factory that throws rejects start() with an error naming WebSocketPlugin({ routes }) and the entry's index in THIS declared array, not its position among the factories.

Duplicate paths throw exactly as two imperative route() calls with the same path would.

Plugin-level ingress behaviours wrapped around every route's onMessage — the WebSocket arm of the transport-neutral behaviour chain shared with the queue, scheduler, and messaging plugins (IIngressBehavior in @setu-ts/common).

Each behaviour observes an IngressContext carrying kind: 'websocket', the route path as name, and the frame as payload, and runs in declared order ahead of the handler. A behaviour that returns without calling next() short-circuits: the handler never sees the frame. A behaviour that throws is routed to the route's onError, exactly as a failing handler is. Behaviours are plugin-level by design; there is no route-level behaviors arm (guards are the per-route mechanism).

Configuring a behaviour makes the dispatch result promise-mediated while preserving immediate execution for entirely synchronous behaviours. A behaviour that defers next() delays the wrapped handler. With no behaviours configured, dispatch is byte-identical to the pre-chain behaviour: a direct, synchronous invoke.

No startup gate is needed here, unlike the queue, scheduler, and messaging arms: a frame cannot arrive before its socket is open, and the application does not serve until after onInit has resolved the chain.

Instance entries are handed to the service at register(); factory entries are resolved in the onInit phase and a throwing factory rejects start() naming WebSocketPlugin({ behaviors }) and the entry's index in THIS declared array.