Interface WebSocketHandler
public interface WebSocketHandler
Handler for a WebSocket session.A server
WebSocketHandler
is mapped to requests withSimpleUrlHandlerMapping
andWebSocketHandlerAdapter
. A clientWebSocketHandler
is passed to theWebSocketClient
execute method.Use
session.receive()
to compose on the inbound message stream, andsession.send(publisher)
for the outbound message stream. Below is an example, combined flow to process inbound and to send outbound messages:class ExampleHandler implements WebSocketHandler { @Override public Mono<Void> handle(WebSocketSession session) { Flux<WebSocketMessage> output = session.receive() .doOnNext(message -> { // ... }) .concatMap(message -> { // ... }) .map(value -> session.textMessage("Echo " + value)); return session.send(output); } }
If processing inbound and sending outbound messages are independent streams, they can be joined together with the "zip" operator:
class ExampleHandler implements WebSocketHandler { @Override public Mono<Void> handle(WebSocketSession session) { Mono<Void> input = session.receive() .doOnNext(message -> { // ... }) .concatMap(message -> { // ... }) .then(); Flux<String> source = ... ; Mono<Void> output = session.send(source.map(session::textMessage)); return Mono.zip(input, output).then(); } }
A
WebSocketHandler
must compose the inbound and outbound streams into a unified flow and return aMono<Void>
that reflects the completion of that flow. That means there is no need to check if the connection is open, since Reactive Streams signals will terminate activity. The inbound stream receives a completion/error signal, and the outbound stream receives a cancellation signal.- Since:
- 5.0
- Author:
- Rossen Stoyanchev
Method Summary
All Methods Instance Methods Abstract Methods Default Methods Modifier and Type Method Description default List<String>
getSubProtocols()
Return the list of sub-protocols supported by this handler.reactor.core.publisher.Mono<Void>
handle(WebSocketSession session)
Invoked when a new WebSocket connection is established, and allows handling of the session.
Method Detail
getSubProtocols
default List<String> getSubProtocols()
Return the list of sub-protocols supported by this handler.By default an empty list is returned.
handle
reactor.core.publisher.Mono<Void> handle(WebSocketSession session)
Invoked when a new WebSocket connection is established, and allows handling of the session.See the class-level doc and the reference for more details and examples of how to handle the session.
- Parameters:
session
- the session to handle- Returns:
- indicates when appilcation handling of the session is complete, which should reflect the completion of the inbound message stream (i.e. connection closing) and possibly the completion of the outbound message stream and the writing of messages.