Additional support for storage classes

- String constants to avoid clients having to hard-code names
- Remove restriction on CopyObject against copying an object to itself (it works and can be useful)
- Add the ability to specify extra metadata when copying an object, e.g. to change storage class
- A test demonstrating various aspects of storage classes

apis/Google.Cloud.Storage.V1/Google.Cloud.Storage.V1.IntegrationTests/CopyObjectTest.cs

@@ -15,6 +15,7 @@
 using System;
 using System.Linq;
 using Xunit;
+using Object = Google.Apis.Storage.v1.Data.Object;
 
 namespace Google.Cloud.Storage.V1.IntegrationTests
 {
@@ -30,14 +31,6 @@ public CopyObjectTest(StorageFixture fixture)
             _fixture = fixture;
         }
 
-        [Fact]
-        public void DestinationEqualsSourceIsProhibited()
-        {
-            var bucket = _fixture.ReadBucket;
-            var name = _fixture.SmallObject;
-            Assert.Throws<ArgumentException>(() => _fixture.Client.CopyObject(bucket, name, bucket, name));
-        }
-
         [Fact]
         public void CopySpecificGeneration()
         {
@@ -70,5 +63,28 @@ public void CopyLatestGeneration()
 
             ValidateData(_fixture.SingleVersionBucket, destName, _fixture.LargeContent);
         }
+
+        [Fact]
+        public void NoMetadataOverride()
+        {
+            var destName = GenerateName();
+            _fixture.Client.CopyObject(
+                _fixture.ReadBucket, _fixture.SmallThenLargeObject,
+                _fixture.SingleVersionBucket, destName);
+            Object fetched = _fixture.Client.GetObject(_fixture.SingleVersionBucket, destName);
+            Assert.Equal("text/plain", fetched.ContentType);
+        }
+
+        [Fact]
+        public void MetadataOverride()
+        {
+            var destName = GenerateName();
+            _fixture.Client.CopyObject(
+                _fixture.ReadBucket, _fixture.SmallThenLargeObject,
+                _fixture.SingleVersionBucket, destName,
+                new CopyObjectOptions { ExtraMetadata = new Object { ContentType = "text/html" } });
+            Object fetched = _fixture.Client.GetObject(_fixture.SingleVersionBucket, destName);
+            Assert.Equal("text/html", fetched.ContentType);
+        }
     }
 }

apis/Google.Cloud.Storage.V1/Google.Cloud.Storage.V1.IntegrationTests/StorageClassTest.cs

@@ -0,0 +1,76 @@
+// Copyright 2017 Google Inc. 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.
+// You may obtain a copy of the License at
+// 
+//     http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License 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.
+
+using Google.Apis.Storage.v1.Data;
+using Xunit;
+using Object = Google.Apis.Storage.v1.Data.Object;
+
+namespace Google.Cloud.Storage.V1.IntegrationTests
+{
+    [Collection(nameof(StorageFixture))]
+    public class StorageClassTest
+    {
+        private readonly StorageFixture _fixture;
+
+        public StorageClassTest(StorageFixture fixture)
+        {
+            _fixture = fixture;
+        }
+
+        // Multi-step test to check:
+        // - Create a bucket with a storage class of regional
+        // - That storage class is used when creating a new object
+        // - If we rewrite the object to a different storage class, that change sticks
+        // - If we update the bucket's default storage class, creating a new object uses that new class
+        [Fact]
+        public void CreateBucketAndObjects()
+        {
+            // Note: this test may fail if the project location prevents multi-regional storage.
+            string initialBucketStorageClass = StorageClasses.MultiRegional;
+            string updatedObjectStorageClass = StorageClasses.Coldline;
+            string updatedBucketStorageClass = StorageClasses.Nearline;
+
+            string bucketName = _fixture.BucketPrefix + "storage-classes";
+            string objectName = TestHelpers.GenerateName();
+            var client = _fixture.Client;
+
+            client.CreateBucket(_fixture.ProjectId, new Bucket { Name = bucketName, StorageClass = initialBucketStorageClass });
+            _fixture.RegisterBucketToDelete(bucketName);
+
+            var bucket = client.GetBucket(bucketName);
+            Assert.Equal(initialBucketStorageClass, bucket.StorageClass);
+
+            var obj = client.UploadObject(bucketName, objectName, "application/octet-stream", TestHelpers.GenerateData(100));
+            Assert.Equal(initialBucketStorageClass, obj.StorageClass);
+
+            // Change storage class via a rewrite
+            var options = new CopyObjectOptions
+            {
+                ExtraMetadata = new Object { StorageClass = updatedObjectStorageClass }
+            };
+            client.CopyObject(bucketName, objectName, bucketName, objectName, options);
+
+            // Fetch separately rather than trusting the return value of CopyObject...
+            obj = client.GetObject(bucketName, objectName);
+            Assert.Equal(updatedObjectStorageClass, obj.StorageClass);
+
+            bucket.StorageClass = updatedBucketStorageClass;
+            client.UpdateBucket(bucket);
+            string objectName2 = TestHelpers.GenerateName();
+
+            var obj2 = client.UploadObject(bucketName, objectName2, "application/octet-stream", TestHelpers.GenerateData(100));
+            Assert.Equal(updatedBucketStorageClass, obj2.StorageClass);
+        }
+    }
+}

apis/Google.Cloud.Storage.V1/Google.Cloud.Storage.V1/CopyObjectOptions.cs

@@ -16,6 +16,7 @@
 using System;
 using static Google.Apis.Storage.v1.ObjectsResource;
 using static Google.Apis.Storage.v1.ObjectsResource.RewriteRequest;
+using Object = Google.Apis.Storage.v1.Data.Object;
 
 namespace Google.Cloud.Storage.V1
 {
@@ -90,6 +91,13 @@ public sealed class CopyObjectOptions
         /// </summary>
         public long? IfSourceMetagenerationNotMatch { get; set; }
 
+        /// <summary>
+        /// Additional object metadata for the new object. This can be used to specify the storage
+        /// class of the new object, the content type etc. If this property is not set, the existing
+        /// object metadata will be used unchanged.
+        /// </summary>
+        public Object ExtraMetadata { get; set; }
+
         internal void ModifyRequest(RewriteRequest request)
         {
             // Note the use of ArgumentException here, as this will basically be the result of invalid

apis/Google.Cloud.Storage.V1/Google.Cloud.Storage.V1/StorageClasses.cs

@@ -0,0 +1,59 @@
+// Copyright 2017 Google Inc. 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.
+// You may obtain a copy of the License at
+// 
+//     http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License 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.
+
+using Google.Apis.Storage.v1.Data;
+
+namespace Google.Cloud.Storage.V1
+{
+    /// <summary>
+    /// String constants for the names of the storage classes, as used in <see cref="Bucket.StorageClass"/>
+    /// and <see cref="Object.StorageClass"/>. See https://cloud.google.com/storage/docs/storage-classes for details.
+    /// </summary>
+    public static class StorageClasses
+    {
+        /// <summary>
+        /// Name for the Multi-Regional storage class.
+        /// </summary>
+        public const string MultiRegional = "MULTI_REGIONAL";
+
+        /// <summary>
+        /// Name for the Regional storage class.
+        /// </summary>
+        public const string Regional = "REGIONAL";
+
+        /// <summary>
+        /// Name for the Nearline storage class.
+        /// </summary>
+        public const string Nearline = "NEARLINE";
+
+        /// <summary>
+        /// Name for the Coldline storage class.
+        /// </summary>
+        public const string Coldline = "COLDLINE";
+
+        /// <summary>
+        /// Name of the Standard storage class, which is equivalent to
+        /// Multi-Regional or Regional depending on the location.
+        /// </summary>
+        public const string Standard = "STANDARD";
+
+        /// <summary>
+        /// Name of the Durable Reduced Availability (DRA) storage class.
+        /// Use of this storage class is not recommended; Regional storage has
+        /// lower pricing for some operations but otherwise the same pricing structure,
+        /// and better performance/availability.
+        /// </summary>
+        public const string DurableReducedAvailability = "DURABLE_REDUCED_AVAILABILITY";
+    }
+}

apis/Google.Cloud.Storage.V1/Google.Cloud.Storage.V1/StorageClient.CopyObject.cs

@@ -31,7 +31,6 @@ public abstract partial class StorageClient
         /// <param name="destinationObjectName">The name of the object within the destination bucket. Must not be null.</param>
         /// <param name="options">Additional options for the fetch operation. May be null, in which case appropriate
         /// defaults will be used.</param>
-        /// <exception cref="ArgumentException">The arguments attempt to copy an object to itself.</exception>
         /// <returns>The <see cref="Object"/> representation of the new storage object resulting from the copy.</returns>
         public virtual Object CopyObject(
             string sourceBucket,
@@ -53,7 +52,6 @@ public virtual Object CopyObject(
         /// <param name="destinationObjectName">The name of the object within the destination bucket. Must not be null.</param>
         /// <param name="options">Additional options for the fetch operation. May be null, in which case appropriate
         /// defaults will be used.</param>
-        /// <exception cref="ArgumentException">The arguments attempt to copy an object to itself.</exception>
         /// <param name="cancellationToken">The token to monitor for cancellation requests.</param>
         /// <returns>A task representing the asynchronous operation, with a result returning the
         /// <see cref="Object"/> representation of the new storage object resulting from the copy.</returns>

apis/Google.Cloud.Storage.V1/Google.Cloud.Storage.V1/StorageClientImpl.CopyObject.cs

@@ -71,11 +71,8 @@ private ObjectsResource.RewriteRequest CreateCopyObjectRequest(
             GaxPreconditions.CheckNotNull(sourceObjectName, nameof(sourceObjectName));
             GaxPreconditions.CheckNotNull(destinationBucket, nameof(destinationBucket));
             GaxPreconditions.CheckNotNull(destinationObjectName, nameof(destinationObjectName));
-            if (destinationBucket == sourceBucket && destinationObjectName == sourceObjectName)
-            {
-                throw new ArgumentException("Cannot copy an object to itself. Specify either a different destination bucket or a different destination object name");
-            }
-            var request = Service.Objects.Rewrite(new Object(), sourceBucket, sourceObjectName, destinationBucket, destinationObjectName);
+            Object obj = options?.ExtraMetadata ?? new Object();
+            var request = Service.Objects.Rewrite(obj, sourceBucket, sourceObjectName, destinationBucket, destinationObjectName);
             options?.ModifyRequest(request);
             return request;
         }