如何用 JavaScript 编写 RSocket 客户端

Question

我尝试用 Java 实现一个 RSocket 服务器，用 JavaScript 实现一个客户端，但我无法调用后端中的任何方法。

Java 服务器

public final class RawServer {
    public static void main(String[] args) {
        RSocketFactory.receive()
                .acceptor((setup, sendingSocket) -> Mono.just(new DefaultSimpleService()))
                .transport(WebsocketServerTransport.create("localhost", 8801))
                .start()
                .block()
                .onClose()
                .block();
    }

    private static final class DefaultSimpleService extends AbstractRSocket {
        private ObjectMapper jsonMapper = new ObjectMapper();

        @Override
        public Flux<Payload> requestStream(Payload payload) {
            return Mono.just(payload.getDataUtf8())
                    .map(json -> {
                        try {
                            return jsonMapper.readValue(json, Message.class);
                        } catch (IOException e) {
                            e.printStackTrace();
                            return null;
                        }
                    })
                    .doOnNext(msg -> System.out.println("got message " + msg.message))
                    .flatMapMany(msg -> Flux.range(0, 5)
                            .map(count -> msg.message + " #" + count))
                    .map(message -> DefaultPayload.create(message));
        }
    }
}

public class Message {

    public final String message;

    @JsonCreator
    public Message(@JsonProperty("message") String message) {
        this.message = message;
    }
}

JavaScript 客户端

    import { RSocketClient, JsonSerializers } from "rsocket-core";
    import RSocketWebSocketClient from "rsocket-websocket-client";

    const transport = new RSocketWebSocketClient({
        url: "ws://localhost:8801"
      });

      const client = new RSocketClient({
        // send/receive JSON objects instead of strings/buffers
        serializers: JsonSerializers,
        setup: {
          // ms btw sending keepalive to server
          keepAlive: 60000,
          // ms timeout if no keepalive response
          lifetime: 180000,
          // format of `data`
          dataMimeType: "application/json",
          // format of `metadata`
          metadataMimeType: "application/json"
        },
        transport
      });
      client.connect().subscribe({
        onComplete: socket => {
          socket.requestStream({
            data: { message: "hello from javascript!" },
            metadata: null
          });
        },
        onError: error => {
          console.log("got error");
          console.error(error);
        },
        onSubscribe: cancel => {
          /* call cancel() to abort */
          console.log("subscribe!");
          console.log(cancel);
          // cancel.cancel();
        }
      });

WebSocket 连接似乎已建立，但没有消息推送到服务器。我该怎么做？

我还用 Java 实现了客户端，它工作得很好。我找到的 JavaScript 示例是 https://github.com/rsocket/rsocket-js/blob/master/docs/01-client-configuration.md，但我无法使其工作。

Answer 1

更多关于 RSocket 的例子你可以访问我的个人博客http://kojotdev.com/2019/09/rsocket-examples-java-javascript-spring-webflux/

好的，我想通了。首先，我们需要修复我们的服务器以返回正确的 JSON 对象。

@Override
public Flux<Payload> requestStream(Payload payload) {
    log.info("got requestStream in Server");
    log.info(payload.getDataUtf8());
    return Mono.just(payload.getDataUtf8())
            .map(payloadString -> MessageMapper.jsonToMessage(payloadString))
            .flatMapMany(msg -> Flux.range(0, 5)
                    .map(count -> msg.message + " | requestStream from Server #" + count)
                    .map(responseText -> new Message(responseText))
                    .map(responseMessage -> MessageMapper.messageToJson(responseMessage)))
            .map(message -> DefaultPayload.create(message));
}

然后，在我们的 JavaScript 客户端中，我们需要将 socket.requestStream 方法更改为：

socket
  .requestStream({
    data: { message: "request - stream from javascript!" },
    metadata: ""
  })
  .subscribe({
    onComplete: () => console.log("requestStream done"),
    onError: error => {
      console.log("got error with requestStream");
      console.error(error);
    },
    onNext: value => {
      // console.log("got next value in requestStream..");
      console.log(value.data);
    },
    // Nothing happens until `request(n)` is called
    onSubscribe: sub => {
      console.log("subscribe request Stream!");
      sub.request(7);
    }
  });

其他一切都和前面的例子一样。 有用的链接：

• 客户端 API https://github.com/rsocket/rsocket-js/blob/master/docs/02-client-api.md
• 流动 API https://github.com/rsocket/rsocket-js/blob/master/docs/03-flowable-api.md
• RSocket 示例（Java、JavaScript、Spring WebFlux）http://kojotdev.com/2019/09/rsocket-examples-java-javascript-spring-webflux/