introducing websockets

pom.xml

@@ -51,9 +51,10 @@
 			<artifactId>spring-boot-devtools</artifactId>
 			<scope>runtime</scope>
 		</dependency>
-
-
-
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-websocket</artifactId>
+		</dependency>
 	</dependencies>
 
 	<build>

src/main/java/com/delebarre/bookappbackend/config/WebSocketConfig.java

@@ -0,0 +1,23 @@
+package com.delebarre.bookappbackend.config;
+
+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("/ws").setAllowedOrigins("*").withSockJS();
+    }
+}

src/main/java/com/delebarre/bookappbackend/controller/BookController.java

@@ -8,6 +8,10 @@
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.*;
 
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.messaging.simp.SimpMessagingTemplate;
+import org.springframework.web.bind.annotation.*;
+
 import java.util.List;
 import java.util.Optional;
 
@@ -19,6 +23,8 @@ public class BookController {
 
     private final BookService bookService;
 
+    private final SimpMessagingTemplate messagingTemplate;
+
     @CrossOrigin(origins = "*")
     @GetMapping("/all")
     public List<Book> getAllBooks() {
@@ -40,6 +46,7 @@ public ResponseEntity<?> createBook(
         try {
             Book book;
             book = bookService.createBook(olid);
+            messagingTemplate.convertAndSend("/topic/books", "update");
 
             return ResponseEntity.status(HttpStatus.CREATED).body(book);
         } catch (BookAlreadyExistsException e) {
@@ -53,13 +60,16 @@ public ResponseEntity<?> createBook(
     @PutMapping
     public ResponseEntity<Book> updateBook(@RequestParam String id, @RequestBody Book book) {
         Book updatedBook = bookService.updateBook(id, book);
+        messagingTemplate.convertAndSend("/topic/books", "update");
         return ResponseEntity.ok(updatedBook);
     }
 
     @CrossOrigin(origins = "*")
     @DeleteMapping
     public ResponseEntity<?> deleteBook(@RequestParam String id) {
-        return bookService.deleteBook(id);
+        bookService.deleteBook(id);
+        messagingTemplate.convertAndSend("/topic/books", "update");
+        return ResponseEntity.ok().build();
     }
 
     @CrossOrigin(origins = "*")