spring Sping Boot - WebSocket -不显示订阅者

yrdbyhpb 于 2022-12-26 发布在 Spring

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我正在复习基本的Sping Boot WebSocket教程：https://spring.io/guides/gs/messaging-stomp-websocket/
我决定修改它，打印出有多少用户订阅了控制台中的一个频道，但无法计算出几个小时。我已经看到了一些StackOverflow的帖子，但他们没有帮助。最后一个我检查是这样的：https://stackoverflow.com/a/51113021/11200149表示要添加，请尝试以下操作：

@Autowired private SimpUserRegistry simpUserRegistry;

public Set<SimpUser> getUsers() { 
    return simpUserRegistry.getUsers();
}

因此，我将以上内容添加到我的控制器中，更改如下：

@Controller
public class GreetingController {
    @Autowired
    private SimpUserRegistry userRegistry;

    @MessageMapping("/hello")
    @SendTo("/topic/greetings")
    public Greeting greeting(HelloMessage message) throws Exception {
        Set<SimpUser> subscribedUsers = userRegistry.getUsers();
        System.out.println("User amount: " + subscribedUsers.size()); // always prints: 0
        return new Greeting("Hello, " + HtmlUtils.htmlEscape(message.getName()) + "!");
    }
}

这将始终打印0：

System.out.println("User amount: " + subscribedUsers.size());

我来自Socket.IO，所以事情可能会有点不同，因为我看到人们实现了他们自己的手动订阅服务类。在www.example.com上socket.io，这将是小菜一碟，所以我假设Sping Boot 会有这个，但我似乎找不到它。

spring

来源：https://stackoverflow.com/questions/74904902/spring-boot-websocket-doesnt-show-subscribers

1条答案

按热度按时间

k5ifujac1#

也许您可以尝试将自定义HandshakeHandler类添加到注册表中，并覆盖determineUser方法以返回包含订阅者名称的Principal对象，以便SimpUserRegistry可以正常工作。
如果你想看到的效果，下面是我正在尝试.

app.js（通过请求参数发送用户名）

function connect() {
    var socket = new SockJS('/gs-guide-websocket?name=' + $('#name').val());
    stompClient = Stomp.over(socket);
    stompClient.connect({}, function (frame) {
        setConnected(true);
        console.log('Connected: ' + frame);
        stompClient.subscribe('/topic/greetings', function (greeting) {
            showGreeting(JSON.parse(greeting.body).content);
        });
    });
}

自定义类扩展DefaultHandshakeHandler.class

@Component
public class WebSocketHandShakeHandler extends DefaultHandshakeHandler {

    @Override
    protected Principal determineUser(ServerHttpRequest request, WebSocketHandler wsHandler, Map<String, Object> attributes) {
        ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
        HttpServletRequest httpServletRequest = servletRequest.getServletRequest();
        String name = httpServletRequest.getParameter("name");

        return new MyPrincipal(name);
    }
}

自定义对象实现Principal.class

@Data
@NoArgsConstructor
@AllArgsConstructor
public class MyPrincipal implements Principal {
    private String name;
}

Web套接字配置类

@Configuration
@EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
    @Autowired
    private WebSocketHandShakeHandler webSocketHandShakeHandler;

    @Override
    public void configureMessageBroker(MessageBrokerRegistry config) {
        config.enableSimpleBroker("/topic");
        config.setApplicationDestinationPrefixes("/app");
    }

    @Override
    public void registerStompEndpoints(StompEndpointRegistry registry) {
        registry.addEndpoint("/gs-guide-websocket")
                .setHandshakeHandler(webSocketHandShakeHandler)
                .withSockJS();
    }
}

显示所有订阅者

@RestController
public class ApiController {
    @Autowired
    private SimpUserRegistry simpUserRegistry;

    @GetMapping("/users")
    public List<String> connectedEquipments() {
        return this.simpUserRegistry
                .getUsers()
                .stream()
                .map(SimpUser::getName).toList();
    }
}

结果

顺便说一下，您可以检查DefaultSimpUserRegistry.class来观察将名称放入订阅者用户Map的过程。

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