move custom websocket configuration to high-level

motivation: make JettyServer and SteveAppContext as small as possible
to ease the spring boot switch

Author: goekay

src/main/java/de/rwth/idsg/steve/JettyServer.java

@@ -141,7 +141,6 @@ public void start() throws Exception {
 
         if (server != null) {
             server.start();
-            steveAppContext.configureWebSocket();
         }
     }
 

src/main/java/de/rwth/idsg/steve/SteveAppContext.java

@@ -18,7 +18,6 @@
  */
 package de.rwth.idsg.steve;
 
-import jakarta.servlet.DispatcherType;
 import org.apache.cxf.transport.servlet.CXFServlet;
 import org.apache.tomcat.InstanceManager;
 import org.apache.tomcat.SimpleInstanceManager;
@@ -27,29 +26,27 @@
 import org.eclipse.jetty.ee10.servlet.ServletContextHandler;
 import org.eclipse.jetty.ee10.servlet.ServletHolder;
 import org.eclipse.jetty.ee10.webapp.WebAppContext;
-import org.eclipse.jetty.ee10.websocket.server.JettyWebSocketServerContainer;
 import org.eclipse.jetty.rewrite.handler.RedirectPatternRule;
 import org.eclipse.jetty.rewrite.handler.RewriteHandler;
 import org.eclipse.jetty.server.Handler;
 import org.eclipse.jetty.server.handler.ContextHandler;
 import org.eclipse.jetty.server.handler.ContextHandlerCollection;
 import org.eclipse.jetty.server.handler.gzip.GzipHandler;
 import org.eclipse.jetty.util.component.AbstractLifeCycle;
-import org.eclipse.jetty.websocket.core.WebSocketConstants;
 import org.springframework.core.io.ClassPathResource;
 import org.springframework.security.web.context.AbstractSecurityWebApplicationInitializer;
 import org.springframework.web.context.ContextLoaderListener;
 import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
 import org.springframework.web.filter.DelegatingFilterProxy;
 import org.springframework.web.servlet.DispatcherServlet;
 
+import jakarta.servlet.DispatcherType;
+
 import java.io.IOException;
 import java.util.EnumSet;
 import java.util.HashSet;
 
 import static de.rwth.idsg.steve.SteveConfiguration.CONFIG;
-import static de.rwth.idsg.steve.config.WebSocketConfiguration.IDLE_TIMEOUT;
-import static de.rwth.idsg.steve.config.WebSocketConfiguration.MAX_MSG_SIZE;
 
 /**
  * @author Sevket Goekay <[email protected]>
@@ -73,15 +70,6 @@ public ContextHandlerCollection getHandlers() {
         );
     }
 
-    /**
-     * Otherwise, defaults come from {@link WebSocketConstants}
-     */
-    public void configureWebSocket() {
-        JettyWebSocketServerContainer container = JettyWebSocketServerContainer.getContainer(webAppContext.getServletContext());
-        container.setMaxTextMessageSize(MAX_MSG_SIZE);
-        container.setIdleTimeout(IDLE_TIMEOUT);
-    }
-
     private Handler getWebApp() {
         if (!CONFIG.getJetty().isGzipEnabled()) {
             return webAppContext;

src/main/java/de/rwth/idsg/steve/config/WebSocketConfiguration.java

@@ -26,10 +26,12 @@
 import de.rwth.idsg.steve.service.ChargePointRegistrationService;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
+import org.eclipse.jetty.websocket.core.WebSocketConstants;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.web.socket.config.annotation.EnableWebSocket;
 import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
 import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
+import org.springframework.web.socket.server.jetty.JettyRequestUpgradeStrategy;
 import org.springframework.web.socket.server.support.DefaultHandshakeHandler;
 
 import java.time.Duration;
@@ -57,7 +59,7 @@ public class WebSocketConfiguration implements WebSocketConfigurer {
     @Override
     public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
         OcppWebSocketHandshakeHandler handshakeHandler = new OcppWebSocketHandshakeHandler(
-            new DefaultHandshakeHandler(),
+            defaultHandshakeHandler(),
             Lists.newArrayList(ocpp16WebSocketEndpoint, ocpp15WebSocketEndpoint, ocpp12WebSocketEndpoint),
             chargePointRegistrationService
         );
@@ -66,4 +68,20 @@ public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
                 .setHandshakeHandler(handshakeHandler)
                 .setAllowedOrigins("*");
     }
+
+    /**
+     * https://docs.spring.io/spring-framework/reference/web/websocket/server.html#websocket-server-runtime-configuration
+     *
+     * Otherwise, defaults come from {@link WebSocketConstants}
+     */
+    private static DefaultHandshakeHandler defaultHandshakeHandler() {
+        JettyRequestUpgradeStrategy strategy = new JettyRequestUpgradeStrategy();
+
+        strategy.addWebSocketConfigurer(configurable -> {
+            configurable.setMaxTextMessageSize(MAX_MSG_SIZE);
+            configurable.setIdleTimeout(IDLE_TIMEOUT);
+        });
+
+        return new DefaultHandshakeHandler(strategy);
+    }
 }