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/ 5 Years ago, tue, november 19, 2019, 12:00:00
I am trying to add WebSocket functionality to an existing application which uses Spring WebFlux. It uses:
- Spring boot 2.2.1.RELEASE
- Tomcat container
- Configured to serve jsp pages
When I try to connect to it through JavaScript (from inside a jsp page) I am receiving the error "failed: Error during WebSocket handshake: Unexpected response code: 404"
I noted that if I create a controller class mapping url '/ws/event-emitter' (the one mapped in my websocket configuration) accepting GET requests, it receives the requests from Javascript call when it tries to open the websocket connection, which made me more confused.
What am I missing?
After read some tutorials on the Internet I set my configuration as below:
<?xml version="1.0" encoding="UTF-8"?>
4.0.0
org.springframework.boot
spring-boot-starter-parent
2.2.1.RELEASE
br.com.samsung
monitor
0.0.1-SNAPSHOT
monitor
Health Check Monitor
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!--
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-webflux</artifactId>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-jasper</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.projectreactor</groupId>
<artifactId>reactor-spring</artifactId>
<version>1.0.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-mail</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>com.microsoft.sqlserver</groupId>
<artifactId>mssql-jdbc</artifactId>
<scope>test</scope>
</dependency>
<!-- MongoDB -->
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-mongodb</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-releasetrain</artifactId>
<version>Lovelace-SR9</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
@Configuration
public class ReactiveWebSocketConfiguration {
@Autowired
private WebSocketHandler webSocketHandler;
@Bean
public HandlerMapping webSocketHandlerMapping() {
Map<String, WebSocketHandler> map = new HashMap<>();
map.put("/ws/event-emitter", webSocketHandler);
SimpleUrlHandlerMapping handlerMapping = new SimpleUrlHandlerMapping();
handlerMapping.setOrder(Ordered.HIGHEST_PRECEDENCE);
handlerMapping.setUrlMap(map);
return handlerMapping;
}
@Bean
public WebSocketHandlerAdapter handlerAdapter(WebSocketService webSocketService) {
return new WebSocketHandlerAdapter(webSocketService);
}
@Bean
public WebSocketService webSocketService() {
TomcatRequestUpgradeStrategy strategy = new TomcatRequestUpgradeStrategy();
strategy.setMaxSessionIdleTimeout(0L);
return new HandshakeWebSocketService(strategy);
}
}
and the Web socket handler class
@Component
public class ReactiveWebSocketHandler implements WebSocketHandler {
private static final ObjectMapper json = new ObjectMapper();
private Flux<String> eventFlux = Flux.generate(sink -> {
Event event = new Event(randomUUID().toString(), now().toString());
try {
sink.next(json.writeValueAsString(event));
} catch (JsonProcessingException e) {
sink.error(e);
}
});
private Flux<String> intervalFlux = Flux.interval(Duration.ofMillis(1000L))
.zipWith(eventFlux, (time, event) -> event);
@Override
public Mono<Void> handle(WebSocketSession webSocketSession) {
return webSocketSession.send(intervalFlux
.map(webSocketSession::textMessage))
.and(webSocketSession.receive()
.map(WebSocketMessage::getPayloadAsText).log());
}
}
var clientWebSocket = new WebSocket(ws://localhost:6600/ws/event-emitter);
clientWebSocket.onopen = function() {
console.log(clientWebSocket.onopen, clientWebSocket);
console.log(clientWebSocket.readyState, websocketstatus);
clientWebSocket.send(event-me-from-browser);
}
clientWebSocket.onclose = function(error) {
console.log(clientWebSocket.onclose, clientWebSocket, error);
events(Closing connection);
}
clientWebSocket.onerror = function(error) {
console.log(clientWebSocket.onerror, clientWebSocket, error);
events(An error occured);
}
clientWebSocket.onmessage = function(error) {
console.log(clientWebSocket.onmessage, clientWebSocket, error);
events(error.data);
}
function events(responseEvent) {
document.querySelector(.events).innerHTML += responseEvent + <br>;
}
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