如何使用 Spring Boot RSocket 服务器支持 WebSocket 传输？

Question

TLDR：配置一个公开支持 WebSocket 传输的 RSocket 接口的 Spring Boot 应用程序需要什么？

---

我同时学习RSocket和Spring Boot，请多多包涵。

在我的努力中，我已经能够构建一个非常简单和人为的 Spring Boot 应用程序实现，它使用第二个 Spring Boot 应用程序提供/公开的 API，使用 RSocket 作为协议，但是，我只能使用TcpClientTransport 时实现这一点。

从我的角度来看，WebsocketTransport 更有可能被使用并且对于客户端->服务器架构更有用，但是，我还没有找到任何关于如何正确配置 Spring Boot 应用程序的工作示例或文档接受使用 WebSocket 作为传输的 RSocket 消息。

奇怪的是，在我的测试中，我的消费者（客户端）似乎确实建立了与服务器/生产者的 WebSocket 连接，但是，“握手”似乎挂起并且连接从未完全建立。我已经使用 JavaScript 库（rsocket-websocket-client、rsocket-rpc-core 等）和 Java 库（io.rsocket.transport.netty.client.WebsocketClientTransport）进行了测试，服务器似乎表现出相同行为不管。

重申一下，使用 TCPTransport 我可以很好地连接到服务器并调用请求，但是当使用 WebsocketTransport 时，连接永远不会建立。

一个旨在通过 WebsocketClientTransport 支持 RSocket 的 Spring Boot 应用程序需要什么，过去使用 spring-boot-starter-rsocket 作为依赖项？。

服务器

---

pom.xml

...

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.2.0.M5</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>

...

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-rsocket</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>

    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
    </dependency>
</dependencies>

...

application.properties

spring.rsocket.server.port=8081
management.endpoints.enabled-by-default=true
management.endpoints.web.exposure.include=*

SpringBootRSocketServerApplication.java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class SpringBootRSocketServerApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringBootRSocketServerApplication.class, args);
    }
}

用户RSocketController

import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.messaging.handler.annotation.MessageMapping;
import org.springframework.stereotype.Controller;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import java.time.Duration;
import java.util.List;
import java.util.Random;
import java.util.stream.Stream;

@Slf4j
@Controller
public class UserRSocketController {

    @Autowired
    private UserRepository userRepository;

    @MessageMapping("usersList")
    public Mono<List<User>> usersList() {
        log.info("Handling usersList request.");
        return Mono.just(this.userRepository.getUsers());
    }

    @MessageMapping("usersStream")
    Flux<User> usersStream(UserStreamRequest request) {
        log.info("Handling request for usersStream.");
        List<User> users = userRepository.getUsers();
        Stream<User> userStream = Stream.generate(() -> {
            Random rand = new Random();
            return users.get(rand.nextInt(users.size()));
        });
        return Flux.fromStream(userStream).delayElements(Duration.ofSeconds(1));
    }

    @MessageMapping("userById")
    public Mono<User> userById(GetUserByIdRequest request) {
        log.info("Handling request for userById id: {}.", request.getId());
        return Mono.just(this.userRepository.getUserById(request.getId()));
    };
}

启动记录

 :: Spring Boot ::             (v2.2.0.M5)

2019-09-08 21:40:02,986 INFO  [main] org.springframework.boot.StartupInfoLogger: Starting SpringBootRSocketServerApplication on REDACTED with PID 22540 (REDACTED)
2019-09-08 21:40:02,988 INFO  [main] org.springframework.boot.SpringApplication: No active profile set, falling back to default profiles: default
2019-09-08 21:40:04,103 INFO  [main] org.springframework.boot.actuate.endpoint.web.EndpointLinksResolver: Exposing 14 endpoint(s) beneath base path '/actuator'
2019-09-08 21:40:04,475 INFO  [main] org.springframework.boot.rsocket.netty.NettyRSocketServer: Netty RSocket started on port(s): 8081
2019-09-08 21:40:04,494 INFO  [main] org.springframework.boot.web.embedded.netty.NettyWebServer: Netty started on port(s): 8080
2019-09-08 21:40:04,498 INFO  [main] org.springframework.boot.StartupInfoLogger: Started SpringBootRSocketServerApplication in 1.807 seconds (JVM running for 2.883)

消费者/客户

---

ClientConfiguration.java

import io.rsocket.RSocket;
import io.rsocket.RSocketFactory;
import io.rsocket.frame.decoder.PayloadDecoder;
import io.rsocket.transport.ClientTransport;
//import io.rsocket.transport.netty.client.TcpClientTransport;
import io.rsocket.transport.netty.client.WebsocketClientTransport;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.rsocket.MetadataExtractor;
import org.springframework.messaging.rsocket.RSocketRequester;
import org.springframework.messaging.rsocket.RSocketStrategies;
import org.springframework.util.MimeTypeUtils;

@Configuration
public class ClientConfiguration {

    @Bean
    public RSocket rSocket() {
        // ClientTransport transport = TcpClientTransport.create(8081);
        // ^--- TCPTransport works fine

        ClientTransport transport = WebsocketClientTransport.create(8081);
        // ^--- Connection hangs and application startup stalls

        return RSocketFactory
            .connect()
            .mimeType(MetadataExtractor.ROUTING.toString(), MimeTypeUtils.APPLICATION_JSON_VALUE)
            .frameDecoder(PayloadDecoder.ZERO_COPY)
            .transport(transport)
            .start()
            .block();
    }

    @Bean
    RSocketRequester rSocketRequester(RSocketStrategies rSocketStrategies) {
        return RSocketRequester.wrap(rSocket(), MimeTypeUtils.APPLICATION_JSON, MimeTypeUtils.APPLICATION_JSON, rSocketStrategies);
    }
}

启动记录

 :: Spring Boot ::             (v2.2.0.M5)

2019-09-08 21:40:52,331 INFO  [main] org.springframework.boot.StartupInfoLogger: Starting SpringBootRsocketConsumerApplication on REDACTED with PID 18904 (REDACTED)
2019-09-08 21:40:52,334 INFO  [main] org.springframework.boot.SpringApplication: No active profile set, falling back to default profiles: default

Answer 1

您只需要两件事就可以让 RSocket 应用程序使用 websocket 传输公开端点：

首先，您需要 webflux 和 rsocket 依赖项，因为您可能还需要提供网页和静态资源：

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-webflux</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-rsocket</artifactId>
    </dependency>

然后你需要在你的application.properties文件中相应地配置RSocket服务器：

#server.port=8080 this is already the default
spring.rsocket.server.transport=websocket
spring.rsocket.server.mapping-path=/rsocket

您可以在Spring Boot reference documentation about RSocket 中找到更多相关信息。

websocket 客户端现在可以连接到ws://localhost:8080/rsocket。

请注意，从当前的 2.2.0 SNAPSHOT 开始，RSocket 协议已经发展，rsocket-js 库正在迎头赶上，尤其是在元数据支持方面。你会找到a working sample here as well。

在 Java 客户端方面，Spring Boot 为您提供了一个 RSocketRequester.Builder，该RSocketRequester.Builder 已经使用编解码器和拦截器根据您的需求进行了配置和定制：

@Component
public class MyService {

    private final RSocketRequester rsocketRequester;

    public MyService(RSocketRequester.Builder builder) {
        this.rsocketRequester = builder
                .connectWebSocket(URI.create("ws://localhost:8080/rsocket"))
                .block();
    }
}

Answer 2

根据this blog post，要连接的正确端口是通过server.port=8080 配置的端口。

服务器配置

server.port=8080
spring.rsocket.server.port=8081
spring.rsocket.server.mapping-path=/ws
spring.rsocket.server.transport=websocket

Java 消费者客户端配置

import io.rsocket.RSocket;
import io.rsocket.RSocketFactory;
import io.rsocket.frame.decoder.PayloadDecoder;
import io.rsocket.transport.ClientTransport;
import io.rsocket.transport.netty.client.TcpClientTransport;
import io.rsocket.transport.netty.client.WebsocketClientTransport;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.messaging.rsocket.MetadataExtractor;
import org.springframework.messaging.rsocket.RSocketRequester;
import org.springframework.messaging.rsocket.RSocketStrategies;
import org.springframework.util.MimeTypeUtils;

import java.net.URI;
import java.time.Duration;

@Configuration
public class ClientConfiguration {

    @Bean
    public RSocket rSocket() {
        URI websocketUri = URI.create("ws://127.0.0.1:8080/ws");
        WebsocketClientTransport ws = WebsocketClientTransport.create(websocketUri);
        return RSocketFactory
            .connect()
            .mimeType(
                MetadataExtractor.ROUTING.toString(),
                MimeTypeUtils.APPLICATION_JSON_VALUE)
            .frameDecoder(PayloadDecoder.ZERO_COPY)
            .transport(ws)
            .start()
            .block();
    }

    @Bean
    RSocketRequester rSocketRequester(RSocketStrategies rSocketStrategies) {
        return RSocketRequester.wrap(
            rSocket(),
            MimeTypeUtils.APPLICATION_JSON,
            MetadataExtractor.ROUTING,
            rSocketStrategies);
    }
}

JavaScript 客户端配置

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

const transport = new RSocketWebSocketClient({
    url: 'ws://127.0.0.1:8080/ws'
});

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().then((rsocket) => {
    // work with rsocket
});