Spring and Sockets

Reading-notes.md

Spring and Sockets

  • How to complete this guide?

  • create a repo, after that clone int in your machine.
  • Create a Web Controller.

Manual Initialization

1- Navigate to https://start.spring.io. This service pulls in all the dependencies you need for an application and does most of the setup for you.

2- Choose either Gradle or Maven and the language you want to use. This guide assumes that you chose Java.

3- Click Dependencies and select Spring Web, Thymeleaf, and Spring Boot DevTools.

4- Click Generate.

5- Download the resulting ZIP file, which is an archive of a web application that is configured with your choices.

Create a Message-handling Controller In Spring’s approach to working with STOMP messaging, STOMP messages can be routed to @Controller classes. The following listing shows: package com.example.messagingstompwebsocket; import org.springframework.messaging.handler.annotation.MessageMapping; import org.springframework.messaging.handler.annotation.SendTo; import org.springframework.stereotype.Controller; import org.springframework.web.util.HtmlUtils; @Controller public class GreetingController { @MessageMapping(“/hello”) @SendTo(“/topic/greetings”) public Greeting greeting(HelloMessage message) throws Exception { Thread.sleep(1000); // simulated delay return new Greeting(“Hello, “ + HtmlUtils.htmlEscape(message.getName()) + “!”); } } The @MessageMapping annotation ensures that, if a message is sent to the /hello destination, the greeting() method is called. ## Configure Spring for STOMP messaging You can configure Spring to enable WebSocket and STOMP messaging. package com.example.messagingstompwebsocket; import org.springframework.context.annotation.Configuration; import org.springframework.messaging.simp.config.MessageBrokerRegistry; import org.springframework.web.socket.config.annotation.EnableWebSocketMessageBroker; import org.springframework.web.socket.config.annotation.StompEndpointRegistry; import org.springframework.web.socket.config.annotation.WebSocketMessageBrokerConfigurer; @Configuration @EnableWebSocketMessageBroker public class WebSocketConfig implements WebSocketMessageBrokerConfigurer { @Override public void configureMessageBroker(MessageBrokerRegistry config) { config.enableSimpleBroker(“/topic”); config.setApplicationDestinationPrefixes(“/app”); } @Override public void registerStompEndpoints(StompEndpointRegistry registry) { registry.addEndpoint(“/gs-guide-websocket”).withSockJS();} }

WebSocketConfig is annotated with @Configuration to indicate that it is a Spring configuration class. It is also annotated with @EnableWebSocketMessageBroker. As its name suggests, @EnableWebSocketMessageBroker enables WebSocket message handling, backed by a message broker.