changes

src/main/java/ai/giskard/learnspringwebsockets/LearnSpringWebsocketsApplication.java

@@ -3,6 +3,7 @@ package ai.giskard.learnspringwebsockets;
 import jakarta.servlet.FilterChain;
 import jakarta.servlet.ServletException;
 import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletRequestWrapper;
 import jakarta.servlet.http.HttpServletResponse;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
@@ -11,7 +12,10 @@ import org.springframework.web.filter.OncePerRequestFilter;
 
 import java.io.IOException;
 import java.text.MessageFormat;
+import java.util.Collections;
 import java.util.Enumeration;
+import java.util.List;
+import java.util.StringTokenizer;
 
 @SpringBootApplication
 public class LearnSpringWebsocketsApplication {
@@ -26,15 +30,25 @@ public class LearnSpringWebsocketsApplication {
         @Override
         protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
                 throws ServletException, IOException {
-            Enumeration<String> headerNames = request.getHeaderNames();
-            System.out.println("!!!! HEADERS");
-            if (headerNames != null) {
-                while (headerNames.hasMoreElements()) {
-                    String name = headerNames.nextElement();
-                    System.out.println(MessageFormat.format("Header:{0} -- {1}", name, request.getHeader(name)));
+
+            final HttpServletRequestWrapper reqWrapper = new HttpServletRequestWrapper(request) {
+                @Override
+                public Enumeration<String> getHeaders(String name) {
+                    if ("connection".equals(name) && "UPGRADE".equals(super.getHeaders(name).nextElement())) {
+                        return Collections.enumeration(Collections.singleton("Upgrade"));
+                    }
+                    return super.getHeaders(name);
+                }
+
+                @Override
+                public String getHeader(String name) {
+                    if ("connection".equals(name) && "UPGRADE".equals(super.getHeader(name))) {
+                        return "Upgrade";
+                    }
+                    return super.getHeader(name);
                 }
-            }
-            filterChain.doFilter(request, response);
+            };
+            filterChain.doFilter(reqWrapper, response);
         }
     }