Fix dispatch order issue in async request handling

Ensure post-processing logic is executed before re-dispatching during asynchronous request handling

* SpringBootLambdaContainerHandler
- Added logic within the handleRequest method to reprocess the request in cases where an asynchronous request requires re-dispatching.

* AwsAsyncContext
- Added an isDispatchStarted method that returns whether the dispatch has started or not.
- Removed the part where doFilter is directly called within the dispatch function.

Author: leekib

aws-serverless-java-container-core/src/main/java/com/amazonaws/serverless/proxy/internal/servlet/AwsAsyncContext.java

@@ -37,6 +37,7 @@ public class AwsAsyncContext implements AsyncContext {
     private long timeout;
     private AtomicBoolean dispatched;
     private AtomicBoolean completed;
+    private AtomicBoolean dispatchStarted;
 
     private Logger log = LoggerFactory.getLogger(AwsAsyncContext.class);
 
@@ -49,6 +50,7 @@ public AwsAsyncContext(HttpServletRequest request, HttpServletResponse response,
         timeout = 3000;
         dispatched = new AtomicBoolean(false);
         completed = new AtomicBoolean(false);
+        dispatchStarted = new AtomicBoolean(false);
     }
 
     @Override
@@ -68,16 +70,15 @@ public boolean hasOriginalRequestAndResponse() {
 
     @Override
     public void dispatch() {
-        try {
-            log.debug("Dispatching request");
-            if (dispatched.get()) {
-                throw new IllegalStateException("Dispatching already started");
-            }
+        log.debug("Dispatching request");
+        if (dispatched.get()) {
+            throw new IllegalStateException("Dispatching already started");
+        }
+        if (!dispatchStarted.get()) {
+            dispatchStarted.set(true);
+        } else {
             dispatched.set(true);
-            handler.doFilter(req, res, ((AwsServletContext)req.getServletContext()).getServletForPath(req.getRequestURI()));
             notifyListeners(NotificationType.START_ASYNC, null);
-        } catch (ServletException | IOException e) {
-            notifyListeners(NotificationType.ERROR, e);
         }
     }
 
@@ -154,6 +155,10 @@ public boolean isCompleted() {
         return completed.get();
     }
 
+    public boolean isDispatchStarted() {
+        return dispatchStarted.get();
+    }
+
     private void notifyListeners(NotificationType type, Throwable t) {
         listeners.forEach((h) -> {
             try {

aws-serverless-java-container-springboot3/src/main/java/com/amazonaws/serverless/proxy/spring/SpringBootLambdaContainerHandler.java

@@ -22,6 +22,7 @@
 import com.amazonaws.serverless.proxy.spring.embedded.ServerlessReactiveServletEmbeddedServerFactory;
 import com.amazonaws.serverless.proxy.spring.embedded.ServerlessServletEmbeddedServerFactory;
 import com.amazonaws.services.lambda.runtime.Context;
+import jakarta.servlet.AsyncContext;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.boot.WebApplicationType;
@@ -172,9 +173,21 @@ protected void handleRequest(HttpServletRequest containerRequest, AwsHttpServlet
             ((AwsHttpServletRequest)containerRequest).setResponse(containerResponse);
         }
         doFilter(containerRequest, containerResponse, reqServlet);
+        if(requiresAsyncReDispatch(containerRequest)) {
+            doFilter(containerRequest, containerResponse, reqServlet);
+        }
         Timer.stop("SPRINGBOOT2_HANDLE_REQUEST");
     }
 
+    private boolean requiresAsyncReDispatch(HttpServletRequest request) {
+        if (request.isAsyncStarted()) {
+            AsyncContext asyncContext = request.getAsyncContext();
+            return asyncContext instanceof AwsAsyncContext
+                    && ((AwsAsyncContext) asyncContext).isDispatchStarted();
+        }
+        return false;
+    }
+
 
     @Override
     public void initialize()