Added null check for multivalue headers and updated unit tests to address #232

Author: sapessi

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

@@ -42,7 +42,7 @@ public AwsProxyHttpServletRequest readRequest(AwsProxyRequest request, SecurityC
         }
 
         request.setPath(stripBasePath(request.getPath(), config));
-        if (request.getMultiValueHeaders().getFirst(HttpHeaders.CONTENT_TYPE) != null) {
+        if (request.getMultiValueHeaders() != null && request.getMultiValueHeaders().getFirst(HttpHeaders.CONTENT_TYPE) != null) {
             String contentType = request.getMultiValueHeaders().getFirst(HttpHeaders.CONTENT_TYPE);
             // put single as we always expect to have one and only one content type in a request.
             request.getMultiValueHeaders().putSingle(HttpHeaders.CONTENT_TYPE, getContentTypeWithCharset(contentType, config));

aws-serverless-java-container-core/src/test/java/com/amazonaws/serverless/proxy/internal/servlet/AwsProxyHttpServletRequestReaderTest.java

@@ -111,7 +111,7 @@ public void readRequest_contentCharset_appendsCharsetToComplextContentType() {
     }
 
     @Test
-    public void readRequest_validEventEmptyPath_expectExcepion() {
+    public void readRequest_validEventEmptyPath_expectException() {
         try {
             AwsProxyRequest req = new AwsProxyRequestBuilder(null, "GET").build();
             AwsProxyHttpServletRequest servletReq = reader.readRequest(req, null, null, ContainerConfig.defaultConfig());
@@ -123,7 +123,7 @@ public void readRequest_validEventEmptyPath_expectExcepion() {
     }
 
     @Test
-    public void readRequest_invalidEventEmptyMethod_expectExcepion() {
+    public void readRequest_invalidEventEmptyMethod_expectException() {
         try {
             AwsProxyRequest req = new AwsProxyRequestBuilder("/path", null).build();
             reader.readRequest(req, null, null, ContainerConfig.defaultConfig());
@@ -135,7 +135,7 @@ public void readRequest_invalidEventEmptyMethod_expectExcepion() {
     }
 
     @Test
-    public void readRequest_invalidEventEmptyContext_expectExcepion() {
+    public void readRequest_invalidEventEmptyContext_expectException() {
         try {
             AwsProxyRequest req = new AwsProxyRequestBuilder("/path", "GET").build();
             req.setRequestContext(null);
@@ -146,4 +146,31 @@ public void readRequest_invalidEventEmptyContext_expectExcepion() {
             e.printStackTrace();
         }
     }
+
+    @Test
+    public void readRequest_nullHeaders_expectSuccess() {
+        AwsProxyRequest req = new AwsProxyRequestBuilder("/path", "GET").build();
+        req.setMultiValueHeaders(null);
+        try {
+            AwsProxyHttpServletRequest servletReq = reader.readRequest(req, null, null, ContainerConfig.defaultConfig());
+            String headerValue = servletReq.getHeader(HttpHeaders.CONTENT_TYPE);
+            assertNull(headerValue);
+        } catch (InvalidRequestEventException e) {
+            e.printStackTrace();
+            fail("Failed to read request with null headers");
+        }
+    }
+
+    @Test
+    public void readRequest_emptyHeaders_expectSuccess() {
+        AwsProxyRequest req = new AwsProxyRequestBuilder("/path", "GET").build();
+        try {
+            AwsProxyHttpServletRequest servletReq = reader.readRequest(req, null, null, ContainerConfig.defaultConfig());
+            String headerValue = servletReq.getHeader(HttpHeaders.CONTENT_TYPE);
+            assertNull(headerValue);
+        } catch (InvalidRequestEventException e) {
+            e.printStackTrace();
+            fail("Failed to read request with null headers");
+        }
+    }
 }