A simple Real Time streaming example with Spring Webflux.

1. Added an API to generate a real time stream returning numbers.
2. Added Test case to consume that API with a webTestClient.
3. Added a client to consume that API, over the network.

springflux-5-reactive-client-ranjeetkaur/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+	<groupId>com.springboot</groupId>
+	<artifactId>sample</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<packaging>jar</packaging>
+
+	<name>client</name>
+	<description>SpringFlux Sample Client</description>
+
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.0.3.RELEASE</version>
+		<relativePath />
+	</parent>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+		<java.version>1.8</java.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-webflux</artifactId>
+		</dependency>
+
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<executions>
+					<execution>
+						<goals>
+							<goal>repackage</goal>
+						</goals>
+					</execution>
+				</executions>
+				<configuration>
+					<arguments>
+						<argument>--spring.profiles.active=dev</argument>
+					</arguments>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+	<repositories>
+		<repository>
+			<id>spring-releases</id>
+			<url>https://repo.spring.io/libs-release</url>
+		</repository>
+	</repositories>
+	<pluginRepositories>
+		<pluginRepository>
+			<id>spring-releases</id>
+			<url>https://repo.spring.io/libs-release</url>
+		</pluginRepository>
+	</pluginRepositories>
+
+</project>

springflux-5-reactive-client-ranjeetkaur/src/main/java/com/springwebflux/sample/Client.java

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+package com.springwebflux.sample;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.scheduling.annotation.EnableAsync;
+import org.springframework.web.reactive.function.client.WebClient;
+
+/**
+ * @author ranjeetkaur
+ *
+ */
+@SpringBootApplication(scanBasePackages = "com.springwebflux.*")
+@EnableAsync
+public class Client {
+
+    public static void main(String[] args) throws InterruptedException {
+
+        WebClient webClient = WebClient.builder()
+            .baseUrl("http://localhost:8090")
+            .build();
+
+        webClient.get()
+            .uri("/v1/dice")
+            .retrieve()
+            .bodyToFlux(Integer.class)
+            .log();
+
+        Thread.sleep(10000);
+    }
+}

springflux-5-reactive-client-ranjeetkaur/src/main/resources/application.properties

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+server.port =8091

springflux-5-reactive-ranjeetkaur/pom.xml

@@ -0,0 +1,76 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+	<groupId>com.springboot</groupId>
+	<artifactId>sample</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<packaging>jar</packaging>
+
+	<name>webflux-server</name>
+	<description>SpringFlux Sample Server</description>
+
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.0.3.RELEASE</version>
+		<relativePath />
+	</parent>
+
+	<properties>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+		<java.version>1.8</java.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-webflux</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+
+	</dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<executions>
+					<execution>
+						<goals>
+							<goal>repackage</goal>
+						</goals>
+					</execution>
+				</executions>
+				<configuration>
+					<arguments>
+						<argument>--spring.profiles.active=dev</argument>
+					</arguments>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+	<repositories>
+		<repository>
+			<id>spring-releases</id>
+			<url>https://repo.spring.io/libs-release</url>
+		</repository>
+	</repositories>
+	<pluginRepositories>
+		<pluginRepository>
+			<id>spring-releases</id>
+			<url>https://repo.spring.io/libs-release</url>
+		</pluginRepository>
+	</pluginRepositories>
+
+</project>

springflux-5-reactive-ranjeetkaur/src/main/java/com/springwebflux/controller/Controller.java

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+package com.springwebflux.controller;
+
+import java.time.Duration;
+import java.util.Random;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import reactor.core.publisher.Flux;
+
+/**
+ * @author ranjeetkaur
+ *
+ */
+@RestController
+@RequestMapping(value = "/v1")
+public class Controller {
+
+    private static Random random = new Random();
+
+    @GetMapping("/dice")
+    public Flux<Integer> rollDice() {
+        return Flux.interval(Duration.ofSeconds(1))
+            .map(pulse -> random.nextInt(5) + 1);
+    }
+    
+}

springflux-5-reactive-ranjeetkaur/src/main/java/com/springwebflux/sample/Application.java

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+package com.springwebflux.sample;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * @author ranjeetkaur
+ *
+ */
+@SpringBootApplication(scanBasePackages = "com.springwebflux.*")
+public class Application {
+
+    public static void main(String[] args) {
+
+        SpringApplication.run(Application.class, args);
+    }
+}

springflux-5-reactive-ranjeetkaur/src/main/resources/application.properties

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+server.port = 8090

springflux-5-reactive-ranjeetkaur/src/test/java/com/springwebflux/sample/ApplicationTests.java

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+package com.springwebflux.sample;
+
+import java.time.Duration;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.reactive.server.WebTestClient;
+
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+public class ApplicationTests {
+
+    @Autowired
+    private WebTestClient webTestClient;
+
+    @Before
+    private void setUp() {
+        webTestClient =  webTestClient.mutate()
+            .responseTimeout(Duration.ofMillis(10000))
+            .build();
+    }
+
+    @Test
+    public void rollDice() throws InterruptedException {
+        webTestClient.get()
+            .uri("/v1/dice")
+            .exchange()
+            .expectStatus()
+            .isOk()
+            .expectBodyList(Integer.class);
+    }
+}