如何使用Spring WebSocket向STOMP客户端发送ERROR消息？

Question

我使用Spring的STOMP而不是WebSocket实现,使用功能齐全的ActiveMQ代理.当用户SUBSCRIBE访问某个主题时,在成功订阅之前,他们必须通过一些权限逻辑.我正在使用ChannelInterceptor来应用权限逻辑,如下所示:

WebSocketConfig.java:

@EnableWebSocketMessageBroker
public class WebSocketConfig extends AbstractWebSocketMessageBrokerConfigurer {

  @Override
  public void registerStompEndpoints(StompEndpointRegistry registry) {
    registry.addEndpoint("/stomp")
      .setAllowedOrigins("*")
      .withSockJS();
  }

  @Override
  public void configureMessageBroker(MessageBrokerRegistry registry) {
    registry.enableStompBrokerRelay("/topic", "/queue")
      .setRelayHost("relayhost.mydomain.com")
      .setRelayPort(61613);
  }

  @Override
  public void configureClientInboundChannel(ChannelRegistration registration) {
    registration.setInterceptors(new MySubscriptionInterceptor());
  }


}

WebSocketSecurityConfig.java:

public class WebSocketSecurityConfig extends AbstractSecurityWebSocketMessageBrokerConfigurer {

  @Override
  protected void configureInbound(MessageSecurityMetadataSourceRegistry messages) {
    messages
      .simpSubscribeDestMatchers("/stomp/**").authenticated()
      .simpSubscribeDestMatchers("/user/queue/errors").authenticated()
      .anyMessage().denyAll();
  }

}

MySubscriptionInterceptor.java:

public class MySubscriptionInterceptor extends ChannelInterceptorAdapter {

  @Override
  public Message<?> preSend(Message<?> message, MessageChannel channel) {

    StompHeaderAccessor headerAccessor= StompHeaderAccessor.wrap(message);
    Principal principal = headerAccessor.getUser();

    if (StompCommand.SUBSCRIBE.equals(headerAccessor.getCommand())) {
      checkPermissions(principal);
    }

    return message;
  }

  private void checkPermissions(Principal principal) {
    // apply permissions logic
    // throw Exception permissions not sufficient
  }
}

当没有足够权限的客户端尝试订阅受限制的主题时,他们实际上从未接收到来自主题的任何消息,但也不会通知被拒绝订阅的异常.相反,客户端返回一个ActiveMQ代理一无所知的死定订阅.(正常,充分许可的客户端与STOMP端点的交互和主题的工作方式与预期一致.)

在成功连接之后,我已经尝试订阅users/{subscribingUsername}/queue/errors并简单地users/queue/errors使用我的Java测试客户端,但到目前为止,我无法从提供给客户端的服务器获得有关订阅异常的错误消息.这显然不太理想,因为客户端从未被通知他们被拒绝访问.

Answer 1

你不能只从抛出异常MySubscriptionInterceptor的clientInboundChannel,因为最后一个是ExecutorSubscribableChannel,因此async从这些线程的任何异常都与任何再掷给调用者日志结束了- StompSubProtocolHandler.handleMessageFromClient.

但是你可以做的就是像这样clientOutboundChannel使用它:

StompHeaderAccessor headerAccessor = StompHeaderAccessor.create(StompCommand.ERROR);
headerAccessor.setMessage(error.getMessage());

clientOutboundChannel.send(MessageBuilder.createMessage(new byte[0], headerAccessor.getMessageHeaders()));

另一个需要考虑的选项是注释映射:

    @SubscribeMapping("/foo")
    public void handleWithError() {
        throw new IllegalArgumentException("Bad input");
    }

    @MessageExceptionHandler
    @SendToUser("/queue/error")
    public String handleException(IllegalArgumentException ex) {
        return "Got error: " + ex.getMessage();
    }