Hands-On Reactive Programming in Spring 5

Server-side WebSocket API 

WebFlux offers WebSocketHandler as the central interface for handling WebSocket connections. This interface has a method called handle, which accepts WebSocketSession. The WebSocketSession class represents a successful handshake between the client and server and provides access to information, including information about the handshake, session attributes, and the incoming stream of data. In order to learn how to deal with this information, let's consider the following example of responding to the sender with echo messages:

class EchoWebSocketHandler implements WebSocketHandler {           // (1)   @Override                                                       //    public Mono<Void> handle(WebSocketSession session) {            // (2)      return session                                               // (3)         .receive()                                                // (4)         .map(WebSocketMessage ...