Reactive Revolution — Postgres

Reference from: https://app.pluralsight.com/library/courses/allthetalks-session-68/table-of-contents

pom.xml

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
   <modelVersion>4.0.0</modelVersion>
   <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>2.6.4</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.example</groupId>
   <artifactId>service</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>service</name>
   <description>Demo project for Spring Boot</description>
   <properties>
      <java.version>11</java.version>
   </properties>
   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-data-r2dbc</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>io.r2dbc</groupId>
         <artifactId>r2dbc-postgresql</artifactId>
         <scope>runtime</scope>
      </dependency>
      <dependency>
         <groupId>org.projectlombok</groupId>
         <artifactId>lombok</artifactId>
         <optional>true</optional>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
      <dependency>
         <groupId>io.projectreactor</groupId>
         <artifactId>reactor-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>

   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
               <excludes>
                  <exclude>
                     <groupId>org.projectlombok</groupId>
                     <artifactId>lombok</artifactId>
                  </exclude>
               </excludes>
            </configuration>
         </plugin>
      </plugins>
   </build>

</project>

MainApp.java

package com.example.service;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.context.event.ApplicationReadyEvent;
import org.springframework.context.annotation.Bean;
import org.springframework.context.event.EventListener;
import org.springframework.data.annotation.Id;
import org.springframework.data.repository.reactive.ReactiveCrudRepository;
import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.ServerResponse;
import reactor.core.publisher.Flux;

import static org.springframework.web.reactive.function.server.RouterFunctions.route;

@SpringBootApplication
public class ServiceApplication {

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


    @Bean
    public RouterFunction<ServerResponse> routes(ReservationRepository rr) {
        return route()
                .GET("/reservations", request -> ServerResponse.ok().body(rr.findAll(), Reservation.class))
                .build();
    }
}

@Component
class SampleDataInit {
    @Autowired
    private ReservationRepository reservationRepository;

    @EventListener(ApplicationReadyEvent.class)
    public void go() {
        Flux<Reservation> reservationFlux = Flux.just("Neha", "Aravind", "Laxmi", "Rajesh", "Anosh", "Sam", "Alex")
                .map(name -> Reservation.builder().name(name).build())
                .flatMap(r -> this.reservationRepository.save(r));

        this.reservationRepository.deleteAll()
                .thenMany(reservationFlux)
                .thenMany(this.reservationRepository.findAll())
                .subscribe(System.out::println);
    }
}

interface ReservationRepository extends ReactiveCrudRepository<Reservation, Integer> {

}

@AllArgsConstructor
@NoArgsConstructor
@Builder
@Data
class Reservation {
    @Id
    private Integer id;
    private String name;
}

application.properties

spring.r2dbc.url=r2dbc:postgresql://localhost:5432/postgres
spring.r2dbc.username=postgres
spring.r2dbc.password=postgres
#spring.r2dbc.initialization-mode=always

init.sql

CREATE TABLE public.reservation (
   id serial4 NOT NULL,
   "name" varchar NOT NULL
);

Response: http://localhost:8080/reservations

[{"id":8,"name":"Neha"},{"id":9,"name":"Aravind"},{"id":10,"name":"Laxmi"},{"id":11,"name":"Rajesh"},{"id":12,"name":"Anosh"},{"id":13,"name":"Sam"},{"id":14,"name":"Alex"}]