Fixed an issue where NPE would be thrown for empty event (#4922)

Author: zoewangg

.changes/next-release/bugfix-AWSSDKforJavav2-4fd89f7.json

@@ -0,0 +1,6 @@
+{
+    "type": "bugfix",
+    "category": "AWS SDK for Java v2",
+    "contributor": "",
+    "description": "Fixed an issue where NPE would be thrown if there was an empty event in the input for an event streaming operation."
+}

core/aws-core/src/main/java/software/amazon/awssdk/awscore/client/handler/AwsClientHandlerUtils.java

@@ -45,13 +45,15 @@ public static ByteBuffer encodeEventStreamRequestToByteBuffer(SdkHttpFullRequest
         Map<String, HeaderValue> headers = new LinkedHashMap<>();
         request.forEachHeader((name, value) -> headers.put(name, HeaderValue.fromString(firstIfPresent(value))));
 
-        byte[] payload = null;
+        byte[] payload;
         if (request.contentStreamProvider().isPresent()) {
             try {
                 payload = IoUtils.toByteArray(request.contentStreamProvider().get().newStream());
             } catch (IOException e) {
                 throw new UncheckedIOException(e);
             }
+        } else {
+            payload = new byte[0];
         }
 
         return new Message(headers, payload).toByteBuffer();

core/aws-core/src/test/java/software/amazon/awssdk/awscore/client/handler/AwsClientHandlerUtilsTest.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file is distributed
+ * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
+ * express or implied. See the License for the specific language governing
+ * permissions and limitations under the License.
+ */
+
+package software.amazon.awssdk.awscore.client.handler;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.net.URI;
+import java.nio.ByteBuffer;
+import org.junit.jupiter.api.Test;
+import software.amazon.awssdk.http.SdkHttpFullRequest;
+import software.amazon.awssdk.http.SdkHttpMethod;
+import software.amazon.awssdk.utils.StringInputStream;
+
+public class AwsClientHandlerUtilsTest {
+
+    @Test
+    void nonNullPayload_shouldEncodeToEmptyMessage() {
+        SdkHttpFullRequest request = SdkHttpFullRequest.builder()
+                                                       .method(SdkHttpMethod.GET)
+                                                       .uri(URI.create("http://localhost"))
+                                                       .contentStreamProvider(() -> new StringInputStream("test"))
+                                                       .build();
+        ByteBuffer buffer = AwsClientHandlerUtils.encodeEventStreamRequestToByteBuffer(request);
+        assertThat(buffer).isNotNull();
+    }
+
+    @Test
+    void nullPayload_shouldEncodeToEmptyMessage() {
+        SdkHttpFullRequest request = SdkHttpFullRequest.builder()
+                                                       .method(SdkHttpMethod.GET)
+                                                       .uri(URI.create("http://localhost")).build();
+        ByteBuffer buffer = AwsClientHandlerUtils.encodeEventStreamRequestToByteBuffer(request);
+        assertThat(buffer).isNotNull();
+    }
+}

test/protocol-tests/src/main/resources/codegen-resources/restjson/contenttype/service-2.json

@@ -223,6 +223,9 @@
         "HeadersOnlyEvent": {
           "shape": "HeadersOnlyEvent"
         },
+        "EndEvent": {
+          "shape": "EndEvent"
+        },
         "ImplicitPayloadAndHeadersEvent": {
           "shape": "ImplicitPayloadAndHeadersEvent"
         }
@@ -280,6 +283,12 @@
       },
       "event": true
     },
+    "EndEvent":{
+      "type":"structure",
+      "members":{
+      },
+      "event":true
+    },
     "BlobPayloadMember":{"type":"blob"},
     "EventStream": {
       "type": "structure",

test/protocol-tests/src/test/java/software/amazon/awssdk/protocol/tests/RestJsonEventStreamProtocolTest.java

@@ -15,10 +15,22 @@
 
 package software.amazon.awssdk.protocol.tests;
 
+import static com.github.tomakehurst.wiremock.client.WireMock.aResponse;
+import static com.github.tomakehurst.wiremock.client.WireMock.any;
+import static com.github.tomakehurst.wiremock.client.WireMock.anyUrl;
+import static com.github.tomakehurst.wiremock.client.WireMock.equalTo;
+import static com.github.tomakehurst.wiremock.client.WireMock.postRequestedFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.stubFor;
+import static com.github.tomakehurst.wiremock.client.WireMock.verify;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.in;
 
+import com.github.tomakehurst.wiremock.junit5.WireMockRuntimeInfo;
+import com.github.tomakehurst.wiremock.junit5.WireMockTest;
+import io.reactivex.Flowable;
 import java.net.URI;
 import java.nio.charset.StandardCharsets;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import software.amazon.awssdk.core.SdkBytes;
 import software.amazon.awssdk.core.client.config.SdkClientConfiguration;
@@ -27,6 +39,7 @@
 import software.amazon.awssdk.http.SdkHttpFullRequest;
 import software.amazon.awssdk.protocols.json.AwsJsonProtocol;
 import software.amazon.awssdk.protocols.json.AwsJsonProtocolFactory;
+import software.amazon.awssdk.services.protocolrestjsoncontenttype.ProtocolRestJsonContentTypeAsyncClient;
 import software.amazon.awssdk.services.protocolrestjsoncontenttype.model.BlobAndHeadersEvent;
 import software.amazon.awssdk.services.protocolrestjsoncontenttype.model.HeadersOnlyEvent;
 import software.amazon.awssdk.services.protocolrestjsoncontenttype.model.ImplicitPayloadAndHeadersEvent;
@@ -38,9 +51,19 @@
 import software.amazon.awssdk.services.protocolrestjsoncontenttype.transform.ImplicitPayloadAndHeadersEventMarshaller;
 import software.amazon.awssdk.services.protocolrestjsoncontenttype.transform.StringAndHeadersEventMarshaller;
 
+@WireMockTest
 public class RestJsonEventStreamProtocolTest {
     private static final String EVENT_CONTENT_TYPE_HEADER = ":content-type";
 
+    private ProtocolRestJsonContentTypeAsyncClient client;
+
+    @BeforeEach
+    void setup(WireMockRuntimeInfo info) {
+        client = ProtocolRestJsonContentTypeAsyncClient.builder()
+                                                       .endpointOverride(URI.create("http://localhost:" + info.getHttpPort()))
+                                                       .build();
+    }
+
     @Test
     public void implicitPayloadAndHeaders_payloadMemberPresent() {
         ImplicitPayloadAndHeadersEventMarshaller marshaller = new ImplicitPayloadAndHeadersEventMarshaller(protocolFactory());
@@ -91,6 +114,18 @@ public void blobAndHeadersEvent() {
         assertThat(content).isEqualTo("hello rest-json");
     }
 
+    @Test
+    public void containsEmptyEvent_shouldEncodeSuccessfully() {
+        stubFor(any(anyUrl()).willReturn(aResponse().withStatus(200)));
+        client.testEventStream(b -> {
+        }, Flowable.fromArray(InputEventStream.stringAndHeadersEventBuilder().stringPayloadMember(
+                                  "test").build(),
+                              InputEventStream.endEventBuilder().build())).join();
+
+        verify(postRequestedFor(anyUrl())
+                   .withHeader("Content-Type", equalTo("application/vnd.amazon.eventstream")));
+    }
+
     @Test
     public void stringAndHeadersEvent() {
         StringAndHeadersEventMarshaller marshaller = new StringAndHeadersEventMarshaller(protocolFactory());