Extended examples for Spring WebFlux.

Added an example for plain Spring WebFlux in combination with Spring Data MongoDB's tailable cursor to stream data to the client as it arrives in the database. Added Nyancat banner \ö/.

Author: odrotbohm

pom.xml

@@ -69,6 +69,7 @@
 <url>https://repo.spring.io/libs-snapshot</url>
 </repository>
 </repositories>
+
 <pluginRepositories>
 <pluginRepository>
 <id>spring-libs-snapshot</id>

readme.adoc

@@ -2,6 +2,14 @@
 
 This repository contains the sample code for Spring WebFlux's functional web API and consists of the following building blocks:
 
+== A sample for Spring WebFlux
+
+1. An `Event` domain type and a corresponding repository exposing a tailable query method.
+2. An `ApplicationRunner` that creates a capped collection for events and inserts a new one every two seconds.
+3. A Spring WebFlux controller to produce both a Server-Sent Events and JSON stream.
+
+== A sample for Spring WebFlux.fn
+
 1. A `User` domain type and a reactive repository mapped using Spring Data MongoDB.
 2. A `FunctionalWebController` to contain handler functions.
 3. An `@Bean`-Definition for a `RouterFunction` that uses the functional API to configure the mappings of requests to the `FunctionalWebController`.
@@ -12,4 +20,10 @@ This repository contains the sample code for Spring WebFlux's functional web API
 $ git clone https://github.com/olivergierke/spring-five-functional-reactive
 $ cd spring-five-functional-reactive
 $ ./mvnw spring-boot:run
+
+# To see the events inserted on the server streaming to the client
+$ curl -H "Accept: text/event-stream" http://localhost:8080/events
+
+# To trigger the functional controller
 $ curl http://localhost:8080/users
+```

src/main/java/de/olivergierke/examples/spring5/webflux/EventController.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.olivergierke.examples.spring5.webflux;
+
+import lombok.Data;
+import lombok.RequiredArgsConstructor;
+import reactor.core.publisher.Flux;
+
+import java.time.LocalDateTime;
+
+import org.springframework.data.mongodb.core.mapping.Document;
+import org.springframework.data.mongodb.repository.Tailable;
+import org.springframework.data.repository.reactive.ReactiveCrudRepository;
+import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * @author Mark Paluch
+ * @author Oliver Gierke
+ */
+@RestController
+@RequiredArgsConstructor
+class EventController {
+
+private final EventRepository eventRepository;
+
+@GetMapping(path = "/events", produces = { //
+MediaType.APPLICATION_STREAM_JSON_VALUE, //
+MediaType.TEXT_EVENT_STREAM_VALUE //
+})
+Flux<Event> streamEvents() {
+return eventRepository.findPeopleBy();
+}
+}
+
+@Data
+@Document
+class Event {
+
+String id;
+final LocalDateTime eventDate;
+}
+
+interface EventRepository extends ReactiveCrudRepository<Event, String> {
+
+@Tailable
+Flux<Event> findPeopleBy();
+}

src/main/java/de/olivergierke/examples/spring5/webflux/WebfluxDemo.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.olivergierke.examples.spring5.webflux;
+
+import reactor.core.publisher.Flux;
+
+import java.io.IOException;
+import java.time.Duration;
+import java.time.LocalDateTime;
+
+import org.springframework.boot.ApplicationRunner;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.data.mongodb.core.CollectionOptions;
+import org.springframework.data.mongodb.core.MongoOperations;
+import org.springframework.data.mongodb.core.ReactiveMongoOperations;
+
+/**
+ * @author Mark Paluch
+ * @author Oliver Gierke
+ */
+@SpringBootApplication
+public class WebfluxDemo {
+
+public static void main(String[] args) throws IOException {
+SpringApplication.run(WebfluxDemo.class, args);
+}
+
+/**
+ * Application runner to initialize a capped collection for {@link Event}s and insert a new {@link Event} every two
+ * seconds.
+ * 
+ * @param operations
+ * @param reactiveOperations
+ * @return
+ */
+@Bean
+ApplicationRunner onStart(MongoOperations operations, ReactiveMongoOperations reactiveOperations) {
+
+return args -> {
+
+CollectionOptions options = CollectionOptions.empty() //
+.capped() //
+.size(2048) //
+.maxDocuments(1000);
+
+operations.dropCollection(Event.class);
+operations.createCollection(Event.class, options);
+
+Flux.interval(Duration.ofSeconds(2)) //
+.map(counter -> new Event(LocalDateTime.now())) //
+.flatMap(reactiveOperations::save) //
+.log() //
+.subscribe();
+};
+}
+}

src/main/java/de/olivergierke/examples/spring5/User.java renamed to src/main/java/de/olivergierke/examples/spring5/webflux/fn/User.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package de.olivergierke.examples.spring5;
+package de.olivergierke.examples.spring5.webflux.fn;
 
 import lombok.Data;
 

src/main/java/de/olivergierke/examples/spring5/UserRepository.java renamed to src/main/java/de/olivergierke/examples/spring5/webflux/fn/UserRepository.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package de.olivergierke.examples.spring5;
+package de.olivergierke.examples.spring5.webflux.fn;
 
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -48,5 +48,5 @@ interface UserRepository extends Repository<User, String> {
  * @param user
  * @return
  */
-Mono<User> save(Mono<User> user);
+Mono<User> save(User user);
 }

src/main/java/de/olivergierke/examples/spring5/DemoApplication.java renamed to src/main/java/de/olivergierke/examples/spring5/webflux/fn/WebfluxFnConfiguration.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package de.olivergierke.examples.spring5;
+package de.olivergierke.examples.spring5.webflux.fn;
 
 import static org.springframework.web.reactive.function.server.RequestPredicates.*;
 
@@ -22,21 +22,16 @@
 import reactor.core.publisher.Mono;
 
 import org.springframework.boot.ApplicationRunner;
-import org.springframework.boot.SpringApplication;
-import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
 import org.springframework.stereotype.Component;
 import org.springframework.web.reactive.function.server.RouterFunction;
 import org.springframework.web.reactive.function.server.RouterFunctions;
 import org.springframework.web.reactive.function.server.ServerRequest;
 import org.springframework.web.reactive.function.server.ServerResponse;
 
-@SpringBootApplication
-class DemoApplication {
-
-public static void main(String[] args) {
-SpringApplication.run(DemoApplication.class, args);
-}
+@Configuration
+class WebfluxFnConfiguration {
 
 /**
  * Defines the routes mapped to {@link FunctionalUserController}.
@@ -62,7 +57,7 @@ RouterFunction<?> routes(FunctionalUserController controller) {
 ApplicationRunner onStartup(UserRepository repository) {
 
 // We need to call ….block() here to actually execute the call.
-return (args) -> repository.save(Mono.just(new User("Dave Matthews"))).block();
+return (args) -> repository.save(new User("Dave Matthews")).block();
 }
 
 /**
@@ -85,7 +80,7 @@ static class FunctionalUserController {
 Mono<ServerResponse> getUser(ServerRequest request) {
 
 Mono<User> user = Mono.just(request.pathVariable("id")) //
-.then(repository::findById);
+.flatMap(repository::findById);
 
 return ServerResponse.ok().body(user, User.class);
 }

src/main/resources/application.properties

@@ -0,0 +1 @@
+spring.jackson.serialization.write-dates-as-timestamps=false

src/main/resources/banner.txt

@@ -0,0 +1,22 @@
+${AnsiColor.BRIGHT_BLUE}████████████████████████████████████████████████████████████████████████████████
+${AnsiColor.BRIGHT_BLUE}████████████████████████████████████████████████████████████████████████████████
+${AnsiColor.RED}██████████████████${AnsiColor.BRIGHT_BLUE}████████████████${AnsiColor.BLACK}██████████████████████████████${AnsiColor.BRIGHT_BLUE}████████████████
+${AnsiColor.RED}████████████████████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████████████████████████████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}██████████████
+${AnsiColor.BRIGHT_RED}████${AnsiColor.RED}██████████████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████${AnsiColor.MAGENTA}██████████████████████${AnsiColor.WHITE}██████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}████████████
+${AnsiColor.BRIGHT_RED}██████████████████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}████${AnsiColor.MAGENTA}████████████████${AnsiColor.BLACK}████${AnsiColor.MAGENTA}██████${AnsiColor.WHITE}████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}██${AnsiColor.BLACK}████${AnsiColor.BRIGHT_BLUE}██████
+${AnsiColor.BRIGHT_RED}██████████████████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.MAGENTA}████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}████${AnsiColor.BLACK}██${AnsiColor.MAGENTA}██████${AnsiColor.WHITE}██${AnsiColor.BLACK}████${AnsiColor.WHITE}████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}████
+${AnsiColor.BRIGHT_YELLOW}██████████████████${AnsiColor.BRIGHT_RED}████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.MAGENTA}████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████${AnsiColor.MAGENTA}██████${AnsiColor.WHITE}██${AnsiColor.BLACK}██${AnsiColor.WHITE}██████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}████
+${AnsiColor.BRIGHT_YELLOW}██████████████████████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_YELLOW}██████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.MAGENTA}████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████${AnsiColor.BLACK}████████${AnsiColor.WHITE}████████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}████
+${AnsiColor.BRIGHT_YELLOW}████████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.BLACK}██${AnsiColor.BRIGHT_YELLOW}████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.MAGENTA}████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████████████████████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}████
+${AnsiColor.BRIGHT_GREEN}██████████████████${AnsiColor.BRIGHT_YELLOW}██${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.BLACK}████████${AnsiColor.WHITE}██${AnsiColor.MAGENTA}██████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████████████████████████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}██
+${AnsiColor.BRIGHT_GREEN}██████████████████████${AnsiColor.WHITE}████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.MAGENTA}██████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████${AnsiColor.BRIGHT_YELLOW}██${AnsiColor.WHITE}██████████${AnsiColor.BRIGHT_YELLOW}██${AnsiColor.BLACK}██${AnsiColor.WHITE}████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}██
+${AnsiColor.BRIGHT_GREEN}██████████████████████${AnsiColor.BLACK}████${AnsiColor.WHITE}████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.MAGENTA}██████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.BLACK}████${AnsiColor.WHITE}████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}██
+${AnsiColor.BLUE}██████████████████${AnsiColor.BRIGHT_GREEN}████████${AnsiColor.BLACK}██████${AnsiColor.WHITE}██${AnsiColor.MAGENTA}██████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.MAGENTA}████${AnsiColor.WHITE}████████████████${AnsiColor.MAGENTA}████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}██
+${AnsiColor.BLUE}██████████████████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}████${AnsiColor.MAGENTA}██████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████${AnsiColor.BLACK}████████████${AnsiColor.WHITE}████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}████
+${AnsiColor.BRIGHT_BLUE}██████████████████${AnsiColor.BLUE}████${AnsiColor.BLUE}██████${AnsiColor.BLACK}████${AnsiColor.WHITE}██████${AnsiColor.MAGENTA}██████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████████████████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}██████
+${AnsiColor.BRIGHT_BLUE}██████████████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██${AnsiColor.BLACK}████${AnsiColor.WHITE}████████████████████${AnsiColor.BLACK}██████████████████${AnsiColor.BRIGHT_BLUE}████████
+${AnsiColor.BRIGHT_BLUE}████████████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}██████${AnsiColor.BLACK}████████████████████████████████${AnsiColor.WHITE}██${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}████████████
+${AnsiColor.BRIGHT_BLUE}████████████████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}██${AnsiColor.BLACK}██${AnsiColor.WHITE}████${AnsiColor.BRIGHT_BLUE}████████████${AnsiColor.BLACK}██${AnsiColor.WHITE}████${AnsiColor.BLACK}████${AnsiColor.WHITE}████${AnsiColor.BLACK}██${AnsiColor.BRIGHT_BLUE}████████████
+${AnsiColor.BRIGHT_BLUE}████████████████████████${AnsiColor.BLACK}██████${AnsiColor.BRIGHT_BLUE}████${AnsiColor.BLACK}██████${AnsiColor.BRIGHT_BLUE}████████████${AnsiColor.BLACK}██████${AnsiColor.BRIGHT_BLUE}████${AnsiColor.BLACK}██████${AnsiColor.BRIGHT_BLUE}████████████
+████████████████████████████████████████████████████████████████████████████████
+${AnsiColor.BRIGHT_BLUE}:: Meow :: Running Spring Boot ${spring-boot.version} :: \ö/${AnsiColor.BLACK}

src/test/java/de/olivergierke/examples/spring5/reactor/ReactorSample.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2017 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package de.olivergierke.examples.spring5.reactor;
+
+import reactor.core.publisher.Flux;
+import reactor.core.publisher.Mono;
+
+import org.junit.Test;
+
+/**
+ * @author Oliver Gierke
+ */
+public class ReactorSample {
+
+@Test
+public void reactorFundamentals() {
+
+Mono.just("Hello") //
+.map(word -> word.concat(" World!")) //
+.subscribe(System.out::println);
+
+Flux.just("Hello", "World") //
+.flatMap(word -> Flux.fromArray(word.split(""))) //
+.subscribe(System.out::println);
+}
+}