Book Image

Developing Java Applications with Spring and Spring Boot

By : Claudio Eduardo de Oliveira, Greg L. Turnquist, Alex Antonov
Book Image

Developing Java Applications with Spring and Spring Boot

By: Claudio Eduardo de Oliveira, Greg L. Turnquist, Alex Antonov

Overview of this book

Spring Framework has become the most popular framework for Java development. It not only simplifies software development but also improves developer productivity. This book covers effective ways to develop robust applications in Java using Spring. The course is up made of three modules, each one having a take-away relating to building end-to-end java applications. The first module takes the approach of learning Spring frameworks by building applications.You will learn to build APIs and integrate them with popular fraemworks suh as AngularJS, Spring WebFlux, and Spring Data. You will also learn to build microservices using Spring's support for Kotlin. You will learn about the Reactive paradigm in the Spring architecture using Project Reactor. In the second module, after getting hands-on with Spring, you will learn about the most popular tool in the Spring ecosystem-Spring Boot. You will learn to build applications with Spring Boot, bundle them, and deploy them on the cloud. After learning to build applications with Spring Boot, you will be able to use various tests that are an important part of application development. We also cover the important developer tools such as AMQP messaging, websockets, security, and more. This will give you a good functional understanding of scalable development in the Spring ecosystem with Spring Boot. In the third and final module, you will tackle the most important challenges in Java application development with Spring Boot using practical recipes. Including recipes for testing, deployment, monitoring, and securing your applications. This module will also address the functional and technical requirements for building enterprise applications. By the end of the course you will be comfortable with using Spring and Spring Boot to develop Java applications and will have mastered the intricacies of production-grade applications.
Table of Contents (34 chapters)
Title Page - Courses
Copyright and Credits - Courses
Packt Upsell - Courses
Preface
Bibliography
Index

Securing WebSockets


So far, we have secured the chat service and the images service.

Or have we?

Well, we configured chat as the Gateway API for our microservices using Spring Cloud Gateway. To do that, we made it the sole source of HTTP session creation. Given that the session details were also included in forwarded web requests, our Gateway API is nicely buttoned up.

However,  the chat microservice's critical function is brokering WebSocket messages. And we haven't lifted a finger to secure that component. Time to roll up our sleeves and get to work.

Since our WebSocket handlers are stream oriented, we merely need to slip in a parent class that authorizes things when the WebSocket session is configured, as follows:

    abstract class AuthorizedWebSocketHandler 
     implements WebSocketHandler { 
 
       @Override 
       public final Mono<Void> handle(WebSocketSession session) { 
         return session.getHandshakeInfo().getPrincipal() 
          .filter(this::isAuthorized) 
     ...