RSocket with Spring Boot

Introduction

How to use RSocket in Spring Boot? In this article, you’ll discover how to do request-response with RSocket using Spring Boot.

RSocket

It is a connection-oriented, message-driven protocol with built-in flow control at the application level. It works in a browser equally as well as on a server. In fact, a web browser can serve traffic to backend microservices. It is also binary. It works equally well with text and binary data, and the payloads can be fragmented. It models all the interactions that you do in your application as network primitives. This means you can stream data or do Pub/Sub without having to setup an application queue.
-- InfoQ

In this article, you’ll discover how to do request-response with RSocket using Spring Boot.

Step 1: Setup the Server Code

The Project File

In the project’s pom.xml file, you need to add the dependency for rsocket.

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

The Application Properties

In the application.properties file, add the following text:

spring.rsocket.server.port=7000

The Message Class

record Message(
        @JsonProperty("source") String source,
        @JsonProperty("message") String message,
        @JsonProperty("createdAt") long createdAt
) {
    Message {
        createdAt = Instant.now().getEpochSecond();
    }
}

The Controller Class

@Controller
@Slf4j
class RSocketController {

    @MessageMapping("app-socket")
    public Message appSocket(Message message) {
        log.info("Received request: {}", message);
        return message;
    }

}

That’s it for code. Let’s try it.

Step 2: Start The Spring Boot RSocket Server

./mvnw clean package spring-boot:run

Step 4: Send A Command To The Server With The RSocket CLI

Next, download RSocket Client CLI and test cli:

wget -O rsc.jar https://github.com/making/rsc/releases/download/0.5.0/rsc-0.5.0.jar
java -jar rsc.jar --help

Next, you’ll send a message to the running server using the RSocket client:

java -jar rsc.jar --debug --request --data "{\"source\":\"LeadByExamples\",\"message\":\"Hello, RSocket!\"}" --route app-socket tcp://localhost:7000

The Client Output

2020-08-17 08:14:10.584 DEBUG --- [actor-tcp-nio-1] i.r.FrameLogger : sending ->
Frame => Stream ID: 1 Type: REQUEST_RESPONSE Flags: 0b100000000 Length: 74
Metadata:
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 0a 61 70 70 2d 73 6f 63 6b 65 74                |.app-socket     |
+--------+-------------------------------------------------+----------------+
Data:
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 7b 22 73 6f 75 72 63 65 22 3a 22 4c 65 61 64 42 |{"source":"LeadB|
|00000010| 79 45 78 61 6d 70 6c 65 73 22 2c 22 6d 65 73 73 |yExamples","mess|
|00000020| 61 67 65 22 3a 22 48 65 6c 6c 6f 2c 20 52 53 6f |age":"Hello, RSo|
|00000030| 63 6b 65 74 22 7d                               |cket"}          |
+--------+-------------------------------------------------+----------------+
2020-08-17 08:14:10.657 DEBUG --- [actor-tcp-nio-1] i.r.FrameLogger : receiving ->
Frame => Stream ID: 1 Type: NEXT_COMPLETE Flags: 0b1100000 Length: 83
Data:
         +-------------------------------------------------+
         |  0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f |
+--------+-------------------------------------------------+----------------+
|00000000| 7b 22 73 6f 75 72 63 65 22 3a 22 4c 65 61 64 42 |{"source":"LeadB|
|00000010| 79 45 78 61 6d 70 6c 65 73 22 2c 22 6d 65 73 73 |yExamples","mess|
|00000020| 61 67 65 22 3a 22 48 65 6c 6c 6f 2c 20 52 53 6f |age":"Hello, RSo|
|00000030| 63 6b 65 74 22 2c 22 63 72 65 61 74 65 64 41 74 |cket","createdAt|
|00000040| 22 3a 31 35 39 37 36 33 31 33 35 30 7d          |":1597631350}   |
+--------+-------------------------------------------------+----------------+
{"source":"LeadByExamples","message":"Hello, RSocket","createdAt":1597631350}