我是Spring WebFlux的新手,我在此链接中使用Spring WebFlux和Websocket找到了此聊天演示:
https://blog.monkey.codes/how-to-build-a-chat-app-using-webflux-websockets-react/
根据文章,它说:
该应用程序的关键是将WebSocketSessions连接到一个另一个。这是通过连接的传入消息流来实现的每次与全球发布商联系。另一方面,每个会话订阅全球发布者产生的消息。
反应器配置:
@Bean
public UnicastProcessor<Event> eventPublisher(){
return UnicastProcessor.create();
}
@Bean
public Flux<Event> events(UnicastProcessor<Event> eventPublisher) {
return eventPublisher
.replay(25)
.autoConnect();
}
@Bean
public HandlerMapping webSocketMapping(UnicastProcessor<Event> eventPublisher, Flux<Event> events) {
Map<String, Object> map = new HashMap<>();
map.put("/websocket/chat", new ChatSocketHandler(eventPublisher, events));
SimpleUrlHandlerMapping simpleUrlHandlerMapping = new SimpleUrlHandlerMapping();
simpleUrlHandlerMapping.setUrlMap(map);
//Without the order things break :-/
simpleUrlHandlerMapping.setOrder(10);
return simpleUrlHandlerMapping;
}
@Bean
public WebSocketHandlerAdapter handlerAdapter() {
return new WebSocketHandlerAdapter();
}
聊天套接字处理程序:
@Override
public Mono<Void> handle(WebSocketSession session) {
WebSocketMessageSubscriber subscriber = new WebSocketMessageSubscriber(eventPublisher);
session.receive()
.map(WebSocketMessage::getPayloadAsText)
.map(this::toEvent)
.subscribe(subscriber::onNext, subscriber::onError, subscriber::onComplete);
return session.send(outputEvents.map(session::textMessage));
}
private static class WebSocketMessageSubscriber {
private UnicastProcessor<Event> eventPublisher;
private Optional<Event> lastReceivedEvent = Optional.empty();
public WebSocketMessageSubscriber(UnicastProcessor<Event> eventPublisher) {
this.eventPublisher = eventPublisher;
}
public void onNext(Event event) {
lastReceivedEvent = Optional.of(event);
eventPublisher.onNext(event);
}
public void onError(Throwable error) {
//TODO log error
error.printStackTrace();
}
public void onComplete() {
lastReceivedEvent.ifPresent(event -> eventPublisher.onNext(
Event.type(USER_LEFT)
.withPayload()
.user(event.getUser())
.build()));
}
}
[如果一个用户发送了一条消息,则其他用户可以看到此消息,因为它已广播给所有用户。但是,当我阅读代码时,我不明白ConnectableFlux(事件)如何将消息发送到所有Web套接字会话。我也尝试注释UserStats类的代码,但它仍然可以正常工作。谁能向我解释一下?
通过Websocket从服务器向浏览器发送消息的代码是:
session.send(outputEvents.map(session::textMessage))
换句话说,每当事件(消息)被推送到outputEvents通量时,它将通过链接到会话的Websocket发送到浏览器。
之所以像广播一样,是因为每个为每个新WebSocketSession创建的WebSocketMessageSubscriber都会将接收到的所有内容(从浏览器到服务器)发布到eventPublisher上,从而使它在outputEvents Flux上可见。
public void onNext(Event event) {
lastReceivedEvent = Optional.of(event);
eventPublisher.onNext(event);
}
outputEvents通量在所有WebSocketMessageSubscribers中共享,并且通过此通量接收的所有事件都通过Websocket发送回浏览器,包括从该Websocket接收到的事件。
在下面的“全局消息流”中的图片表示outputEvents通量。