Full Stack Reactive with React and Spring WebFlux - Switzerland JUG 2020

You have streaming data and want to expose it as reactive streams with Spring Boot. Great! Spring WebFlux makes that pretty easy. But what about the UI? Can you stream that data to the UI and have it be reactive and constantly updating too?

This session explores techniques for making your app fully reactive with Spring WebFlux and React. Mostly live coding, with plenty of time for Q & A in the midst of it all.

* Blog post: Full Stack Reactive with Spring WebFlux, WebSockets, and React
* Screencast of demo: https://youtu.be/1xpwYe154Ys

Transcript

1. Full Stack Reactive with React and Spring WebFlux Matt Raible | @mraible March 12, 2020 Photo by Lukas Schlagenhauf flickr.com/photos/lschlagenhauf/33223388493
4. Blogger on raibledesigns.com and developer.okta.com/blog Web Developer and Java Champion Father, Skier, Mountain Biker, Whitewater Rafter Open Source Connoisseur Who is Matt Raible? Bus Lover Okta Developer Advocate
8. developer.okta.com
9. What About You?
10. Full Stack Reactive http://bit.ly/webflux-and-react
11. OAuth 2.0 Overview Today’s Agenda What is reactive programming? Introduction to Spring WebFlux Developing an API with WebFlux Handling Streaming Data with React Securing WebFlux and React
12. What is reactive programming? Asynchronous I/O
13. package com.example.io; import lombok.extern.log4j.Log4j2; import org.springframework.util.FileCopyUtils; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.util.function.Consumer; @Log4j2 class Synchronous implements Reader { @Override public void read(File file, Consumer<BytesPayload> consumer) throws IOException { try (FileInputStream in = new FileInputStream(file)) { byte[] data = new byte[FileCopyUtils.BUFFER_SIZE]; int res; while ((res = in.read(data, 0, data.length)) != -1) { consumer.accept(BytesPayload.from(data, res)); } } } }
14. class Asynchronous implements Reader, CompletionHandler<Integer, ByteBuffer> { private int bytesRead; private long position; private AsynchronousFileChannel fileChannel; private Consumer<BytesPayload> consumer; private final ExecutorService executorService = Executors.newFixedThreadPool(10); public void read(File file, Consumer<BytesPayload> c) throws IOException { this.consumer = c; Path path = file.toPath(); this.fileChannel = AsynchronousFileChannel.open(path, Collections.singleton(StandardOpenOption.READ), this.executorService); ByteBuffer buffer = ByteBuffer.allocate(FileCopyUtils.BUFFER_SIZE); this.fileChannel.read(buffer, position, buffer, this); while (this.bytesRead > 0) { this.position = this.position + this.bytesRead; this.fileChannel.read(buffer, this.position, buffer, this); } } @Override public void completed(Integer result, ByteBuffer buffer) { ... } }
15. @Override public void completed(Integer result, ByteBuffer buffer) { this.bytesRead = result; if (this.bytesRead < 0) return; buffer.flip(); byte[] data = new byte[buffer.limit()]; buffer.get(data); consumer.accept(BytesPayload.from(data, data.length)); buffer.clear(); this.position = this.position + this.bytesRead; this.fileChannel.read(buffer, this.position, buffer, this); } @Override public void failed(Throwable exc, ByteBuffer attachment) { log.error(exc); }
16. Reactive Streams
17. Reactive Streams reactive-streams.org
18. Reactive Streams reactive-streams.org
19. Reactive Streams reactive-streams.org
20. Reactive Streams reactive-streams.org
21. Spring WebFlux
22. @SpringBootApplication public class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); } } @Entity class Blog { @Id @GeneratedValue private Long id; private String name; // getters, setters, toString(), etc } @RepositoryRestResource interface BlogRepository extends JpaRepository<Blog, Long> { }
23. Demo: Build a Spring WebFlux API
24. ES6, ES7 and TypeScript ES5: es5.github.io ES6: git.io/es6features ES7: bit.ly/es7features TS: www.typescriptlang.org TS ES7 ES6 ES5
25. @spring_io #springio17 TypeScript
26. “Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js uses an event-driven, non- blocking I/O model that makes it lightweight and efficient. Node.js' package ecosystem, npm, is the largest ecosystem of open source libraries in the world.” https://nodejs.org https://github.com/creationix/nvm
27. Hello World with React http://codepen.io/gaearon/pen/ZpvBNJ?editors=0100 <div id="root"></div> <script> ReactDOM.render( <h1>Hello, world!</h1>, document.getElementById('root') ); </script>
28. Imperative Code if (count > 99) { if (!hasFire()) { addFire(); } } else { if (hasFire()) { removeFire(); } } if (count === 0) { if (hasBadge()) { removeBadge(); } return; } if (!hasBadge()) { addBadge(); } var countText = count > 99 ? "99+" : count.toString(); getBadge().setText(countText);
29. Declarative Code if (count === 0) { return <div className="bell"/>; } else if (count <= 99) { return ( <div className="bell"> <span className="badge">{count}</span> </div> ); } else { return ( <div className="bell onFire"> <span className="badge">99+</span> </div> ); }
30. https://facebook.github.io/create-react-app/
31. Learning React https://vimeo.com/213710634
32. Handling Streaming Data in React Polling with Interval Polling with RxJS WebSocket Server-Sent Events and EventSource RSocket
33. Demo: Build a React Client class ProfileList extends React.Component<ProfileListProps, ProfileListState> { constructor(props: ProfileListProps) { super(props); this.state = { profiles: [], isLoading: false }; } async componentDidMount() { this.setState({isLoading: true}); const response = await fetch('http://localhost:8080/profiles', { headers: { Authorization: 'Bearer ' + this.props.authState.accessToken } }); const data = await response.json(); this.setState({profiles: data, isLoading: false}); } render() { const {profiles, isLoading} = this.state; ... } }
34. @spring_io #springio17 JHipster jhipster.tech JHipster is a development platform to generate, develop and deploy Spring Boot + Angular/React Web applications and Spring microservices.
35. The JHipster Mini-Book v5.0 Available Now! jhipster-book.com 21-points.com @jhipster_book Write your own InfoQ mini-book! github.com/mraible/infoq-mini-book
36. Action! Try Spring WebFlux Try React Try OIDC Explore PWAs Enjoy the experience!
37. DIY: Full Stack Reactive http://bit.ly/webflux-and-react
38. CRUD with React and Spring Boot http://bit.ly/react-boot-crud
39. #LearnAllTheThings
40. developer.okta.com/blog @oktadev
41. Use the Source, Luke! git clone https://github.com/oktadeveloper/okta-spring-webflux-react- example.git https://github.com/oktadeveloper/okta-spring-webflux-react-example
42. Questions? Keep in touch! @starbuxman @mraible Presentation speakerdeck.com/mraible Code github.com/oktadeveloper
43. @oktadev