Bug fix in servlet request impl to null-check headers in case Lambda gets sent an event without the multiValueHeaders property (#281). Also moved the ServletContext to be managed by the ServletRequestReader istead of set on each request by the LambdaContainerHandler. Additional bug fix to set the correct dispatcher type when startAsync is called on the request

Author: sapessi

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

@@ -18,6 +18,7 @@
 import com.amazonaws.serverless.proxy.internal.testutils.Timer;
 import com.amazonaws.serverless.proxy.model.AwsProxyRequest;
 import com.amazonaws.serverless.proxy.model.ContainerConfig;
+import com.amazonaws.serverless.proxy.model.Headers;
 import com.amazonaws.services.lambda.runtime.Context;
 
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
@@ -31,13 +32,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import javax.servlet.AsyncContext;
-import javax.servlet.ReadListener;
-import javax.servlet.RequestDispatcher;
-import javax.servlet.ServletException;
-import javax.servlet.ServletInputStream;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
+import javax.servlet.*;
 import javax.servlet.http.*;
 import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.MediaType;
@@ -119,10 +114,6 @@ public void setResponse(AwsHttpServletResponse response) {
         this.response = response;
     }
 
-    public AwsLambdaServletContainerHandler getContainerHandler() {
-        return containerHandler;
-    }
-
     public void setContainerHandler(AwsLambdaServletContainerHandler containerHandler) {
         this.containerHandler = containerHandler;
     }
@@ -380,6 +371,9 @@ public String getCharacterEncoding() {
     @Override
     public void setCharacterEncoding(String s)
             throws UnsupportedEncodingException {
+        if (request.getMultiValueHeaders() == null) {
+            request.setMultiValueHeaders(new Headers());
+        }
         String currentContentType = request.getMultiValueHeaders().getFirst(HttpHeaders.CONTENT_TYPE);
         if (currentContentType == null || "".equals(currentContentType)) {
             log.debug("Called set character encoding to " + SecurityUtils.crlf(s) + " on a request without a content type. Character encoding will not be set");
@@ -679,6 +673,7 @@ public boolean isAsyncSupported() {
     public AsyncContext startAsync()
             throws IllegalStateException {
         asyncContext = new AwsAsyncContext(this, response, containerHandler);
+        setAttribute(DISPATCHER_TYPE_ATTRIBUTE, DispatcherType.ASYNC);
         log.debug("Starting async context for request: " + SecurityUtils.crlf(request.getRequestContext().getRequestId()));
         return asyncContext;
     }
@@ -688,6 +683,7 @@ public AsyncContext startAsync()
     public AsyncContext startAsync(ServletRequest servletRequest, ServletResponse servletResponse)
             throws IllegalStateException {
         asyncContext = new AwsAsyncContext((HttpServletRequest) servletRequest, (HttpServletResponse) servletResponse, containerHandler);
+        setAttribute(DISPATCHER_TYPE_ATTRIBUTE, DispatcherType.ASYNC);
         log.debug("Starting async context for request: " + SecurityUtils.crlf(request.getRequestContext().getRequestId()));
         return asyncContext;
     }

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

@@ -18,6 +18,7 @@
 import com.amazonaws.serverless.proxy.model.ContainerConfig;
 import com.amazonaws.services.lambda.runtime.Context;
 
+import javax.servlet.ServletContext;
 import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.SecurityContext;
 
@@ -27,11 +28,15 @@
  */
 public class AwsProxyHttpServletRequestReader extends RequestReader<AwsProxyRequest, AwsProxyHttpServletRequest> {
     static final String INVALID_REQUEST_ERROR = "The incoming event is not a valid request from Amazon API Gateway or an Application Load Balancer";
-
+    private ServletContext servletContext;
     //-------------------------------------------------------------
     // Methods - Implementation
     //-------------------------------------------------------------
 
+    public void setServletContext(ServletContext ctx) {
+        servletContext = ctx;
+    }
+
     @Override
     public AwsProxyHttpServletRequest readRequest(AwsProxyRequest request, SecurityContext securityContext, Context lambdaContext, ContainerConfig config)
             throws InvalidRequestEventException {
@@ -48,6 +53,7 @@ public AwsProxyHttpServletRequest readRequest(AwsProxyRequest request, SecurityC
             request.getMultiValueHeaders().putSingle(HttpHeaders.CONTENT_TYPE, getContentTypeWithCharset(contentType, config));
         }
         AwsProxyHttpServletRequest servletRequest = new AwsProxyHttpServletRequest(request, lambdaContext, securityContext, config);
+        servletRequest.setServletContext(servletContext);
         servletRequest.setAttribute(API_GATEWAY_CONTEXT_PROPERTY, request.getRequestContext());
         servletRequest.setAttribute(API_GATEWAY_STAGE_VARS_PROPERTY, request.getStageVariables());
         servletRequest.setAttribute(API_GATEWAY_EVENT_PROPERTY, request);