Trim object metadata keys for PUT and MPU

This brings the V2's behavior in line with 1.x

.changes/next-release/feature-AmazonS3-138feae.json

@@ -0,0 +1,6 @@
+{
+    "type": "feature",
+    "category": "Amazon S3",
+    "contributor": "",
+    "description": "Automatically trim object metadata keys of whitespace for `PutObject` and `CreateMultipartUpload`."
+}

services/s3/src/main/java/software/amazon/awssdk/services/s3/internal/handlers/ObjectMetadataInterceptor.java

@@ -0,0 +1,74 @@
+/*
+ * 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.services.s3.internal.handlers;
+
+import java.util.Map;
+import java.util.stream.Collectors;
+import software.amazon.awssdk.annotations.SdkInternalApi;
+import software.amazon.awssdk.core.SdkRequest;
+import software.amazon.awssdk.core.interceptor.Context;
+import software.amazon.awssdk.core.interceptor.ExecutionAttributes;
+import software.amazon.awssdk.core.interceptor.ExecutionInterceptor;
+import software.amazon.awssdk.core.interceptor.SdkExecutionAttribute;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+import software.amazon.awssdk.utils.StringUtils;
+
+/**
+ * Interceptor that trims object metadata keys of any leading or trailing whitespace for {@code PutObject} and {@code
+ * CreateMultipartUpload}. This behavior is intended to provide the same functionality as in 1.x.
+ */
+@SdkInternalApi
+public final class ObjectMetadataInterceptor implements ExecutionInterceptor {
+    @Override
+    public SdkRequest modifyRequest(Context.ModifyRequest context, ExecutionAttributes executionAttributes) {
+        SdkRequest request = context.request();
+
+        switch (executionAttributes.getAttribute(SdkExecutionAttribute.OPERATION_NAME)) {
+            case "PutObject":
+                return trimMetadataNames((PutObjectRequest) request);
+            case "CreateMultipartUpload":
+                return trimMetadataNames((CreateMultipartUploadRequest) request);
+            default:
+                return request;
+        }
+    }
+
+    private PutObjectRequest trimMetadataNames(PutObjectRequest putObjectRequest) {
+        if (!putObjectRequest.hasMetadata()) {
+            return putObjectRequest;
+        }
+
+        return putObjectRequest.toBuilder()
+            .metadata(trimKeys(putObjectRequest.metadata()))
+            .build();
+    }
+
+    private CreateMultipartUploadRequest trimMetadataNames(CreateMultipartUploadRequest createMultipartUploadRequest) {
+        if (!createMultipartUploadRequest.hasMetadata()) {
+            return createMultipartUploadRequest;
+        }
+
+        return createMultipartUploadRequest.toBuilder()
+                               .metadata(trimKeys(createMultipartUploadRequest.metadata()))
+                               .build();
+    }
+
+    private Map<String, String> trimKeys(Map<String, String> map) {
+        return map.entrySet().stream()
+            .collect(Collectors.toMap(e -> StringUtils.trim(e.getKey()), Map.Entry::getValue));
+    }
+}

services/s3/src/main/resources/codegen-resources/customization.config

@@ -259,7 +259,8 @@
     "software.amazon.awssdk.services.s3.internal.handlers.ExceptionTranslationInterceptor",
     "software.amazon.awssdk.services.s3.internal.handlers.GetObjectInterceptor",
     "software.amazon.awssdk.services.s3.internal.handlers.CopySourceInterceptor",
-    "software.amazon.awssdk.services.s3.internal.handlers.DisablePayloadSigningInterceptor"
+    "software.amazon.awssdk.services.s3.internal.handlers.DisablePayloadSigningInterceptor",
+    "software.amazon.awssdk.services.s3.internal.handlers.ObjectMetadataInterceptor"
   ],
   "internalPlugins": [
     "software.amazon.awssdk.services.s3.internal.s3express.S3ExpressPlugin"

services/s3/src/test/java/software/amazon/awssdk/services/s3/internal/handlers/ObjectMetadataInterceptorTest.java

@@ -0,0 +1,124 @@
+/*
+ * 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.services.s3.internal.handlers;
+
+import static java.util.Arrays.asList;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+import org.junit.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.MethodSource;
+import software.amazon.awssdk.core.SdkRequest;
+import software.amazon.awssdk.core.interceptor.Context;
+import software.amazon.awssdk.core.interceptor.ExecutionAttributes;
+import software.amazon.awssdk.core.interceptor.SdkExecutionAttribute;
+import software.amazon.awssdk.services.s3.model.CreateMultipartUploadRequest;
+import software.amazon.awssdk.services.s3.model.GetObjectRequest;
+import software.amazon.awssdk.services.s3.model.PutObjectRequest;
+
+public class ObjectMetadataInterceptorTest {
+    private static final ObjectMetadataInterceptor INTERCEPTOR = new ObjectMetadataInterceptor();
+
+
+
+    public static List<TestCase> testCases() {
+        return asList(
+            tc(asList("a", "b", "c"), asList("a", "b", "c")),
+            tc(asList(" a ", "b", "c"), asList("a", "b", "c")),
+            tc(asList("   a", "\tb", "\tc"), asList("a", "b", "c")),
+            tc(asList("a\n", "\tb", "\tc\r\n"), asList("a", "b", "c"))
+
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("testCases")
+    public void modifyRequest_putObject_metadataKeysAreTrimmed(TestCase tc) {
+        Map<String, String> metadata = tc.inputKeys.stream()
+            .collect(Collectors.toMap(k -> k, k -> "value"));
+
+        Context.ModifyHttpRequest ctx = mock(Context.ModifyHttpRequest.class);
+
+        PutObjectRequest put = PutObjectRequest.builder()
+            .metadata(metadata)
+            .build();
+
+        when(ctx.request()).thenReturn(put);
+
+        ExecutionAttributes attrs = new ExecutionAttributes();
+        attrs.putAttribute(SdkExecutionAttribute.OPERATION_NAME, "PutObject");
+
+        PutObjectRequest modified = (PutObjectRequest) INTERCEPTOR.modifyRequest(ctx, attrs);
+
+        assertThat(modified.metadata().keySet()).containsExactlyElementsOf(tc.expectedKeys);
+    }
+
+    @ParameterizedTest
+    @MethodSource("testCases")
+    public void modifyRequest_creatMultipartUpload_metadataKeysAreTrimmed(TestCase tc) {
+        Map<String, String> metadata = tc.inputKeys.stream()
+                                                   .collect(Collectors.toMap(k -> k, k -> "value"));
+
+        Context.ModifyHttpRequest ctx = mock(Context.ModifyHttpRequest.class);
+
+        CreateMultipartUploadRequest mpu = CreateMultipartUploadRequest.builder()
+                                                                       .metadata(metadata)
+                                                                       .build();
+
+        when(ctx.request()).thenReturn(mpu);
+
+        ExecutionAttributes attrs = new ExecutionAttributes();
+        attrs.putAttribute(SdkExecutionAttribute.OPERATION_NAME, "CreateMultipartUpload");
+
+        CreateMultipartUploadRequest modified = (CreateMultipartUploadRequest) INTERCEPTOR.modifyRequest(ctx, attrs);
+
+        assertThat(modified.metadata().keySet()).containsExactlyElementsOf(tc.expectedKeys);
+    }
+
+    @Test
+    public void modifyRequest_unknownOperation_ignores() {
+        Context.ModifyHttpRequest ctx = mock(Context.ModifyHttpRequest.class);
+
+        GetObjectRequest get = GetObjectRequest.builder().build();
+
+        when(ctx.request()).thenReturn(get);
+
+        ExecutionAttributes attrs = new ExecutionAttributes();
+        attrs.putAttribute(SdkExecutionAttribute.OPERATION_NAME, "GetObject");
+
+        SdkRequest sdkRequest = INTERCEPTOR.modifyRequest(ctx, attrs);
+
+        assertThat(sdkRequest).isEqualTo(get);
+    }
+
+    private static TestCase tc(List<String> input, List<String> expected) {
+        return new TestCase(input, expected);
+    }
+    private static class TestCase {
+        private List<String> inputKeys;
+        private List<String> expectedKeys;
+
+        public TestCase(List<String> inputKeys, List<String> expectedKeys) {
+            this.inputKeys = inputKeys;
+            this.expectedKeys = expectedKeys;
+        }
+    }
+}