Implement asynchronous support in ODataJsonLightCollectionSerializer

src/Microsoft.OData.Core/JsonLight/ODataJsonLightCollectionSerializer.cs

@@ -9,6 +9,7 @@ namespace Microsoft.OData.JsonLight
     #region Namespaces
 
     using System.Diagnostics;
+    using System.Threading.Tasks;
     using Microsoft.OData.Edm;
 
     #endregion Namespaces
@@ -87,5 +88,73 @@ internal void WriteCollectionEnd()
                 this.JsonWriter.EndObjectScope();
             }
         }
+
+        /// <summary>
+        /// Asynchronously writes the start of a collection.
+        /// </summary>
+        /// <param name="collectionStart">The collection start to write.</param>
+        /// <param name="itemTypeReference">The item type of the collection or null if no metadata is available.</param>
+        internal async Task WriteCollectionStartAsync(ODataCollectionStart collectionStart, IEdmTypeReference itemTypeReference)
+        {
+            Debug.Assert(collectionStart != null, "collectionStart != null");
+
+            if (this.writingTopLevelCollection)
+            {
+                // "{"
+                await this.AsynchronousJsonWriter.StartObjectScopeAsync()
+                    .ConfigureAwait(false);
+
+                // "@odata.context":...
+                await this.WriteContextUriPropertyAsync(
+                    ODataPayloadKind.Collection,
+                    () => ODataContextUrlInfo.Create(collectionStart.SerializationInfo, itemTypeReference))
+                        .ConfigureAwait(false);
+
+                // "@odata.count":...
+                if (collectionStart.Count.HasValue)
+                {
+                    await this.AsynchronousODataAnnotationWriter.WriteInstanceAnnotationNameAsync(ODataAnnotationNames.ODataCount)
+                        .ConfigureAwait(false);
+                    await this.AsynchronousJsonWriter.WriteValueAsync(collectionStart.Count.Value)
+                        .ConfigureAwait(false);
+                }
+
+                // "@odata.nextlink":...
+                if (collectionStart.NextPageLink != null)
+                {
+                    await this.AsynchronousODataAnnotationWriter.WriteInstanceAnnotationNameAsync(ODataAnnotationNames.ODataNextLink)
+                        .ConfigureAwait(false);
+                    await this.AsynchronousJsonWriter.WriteValueAsync(this.UriToString(collectionStart.NextPageLink))
+                        .ConfigureAwait(false);
+                }
+
+                // "value":
+                await this.AsynchronousJsonWriter.WriteValuePropertyNameAsync()
+                    .ConfigureAwait(false);
+            }
+
+            // Write the start of the array for the collection items
+            // "["
+            await this.AsynchronousJsonWriter.StartArrayScopeAsync()
+                .ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Asynchronously writes the end of a collection.
+        /// </summary>
+        internal async Task WriteCollectionEndAsync()
+        {
+            // Write the end of the array for the collection items
+            // "]"
+            await this.AsynchronousJsonWriter.EndArrayScopeAsync()
+                .ConfigureAwait(false);
+
+            if (this.writingTopLevelCollection)
+            {
+                // "}"
+                await this.AsynchronousJsonWriter.EndObjectScopeAsync()
+                    .ConfigureAwait(false);
+            }
+        }
     }
 }

test/FunctionalTests/Microsoft.OData.Core.Tests/JsonLight/ODataJsonLightCollectionSerializerTests.cs

@@ -0,0 +1,243 @@
+//---------------------------------------------------------------------
+// <copyright file="ODataJsonLightCollectionSerializerTests.cs" company="Microsoft">
+//      Copyright (C) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
+// </copyright>
+//---------------------------------------------------------------------
+
+using System;
+using System.IO;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.OData.Edm;
+using Microsoft.OData.JsonLight;
+using Xunit;
+
+namespace Microsoft.OData.Tests.JsonLight
+{
+    /// <summary>
+    /// Unit tests for ODataJsonLightCollectionSerializer.
+    /// </summary>
+    public class ODataJsonLightCollectionSerializerTests
+    {
+        private EdmModel model;
+        private MemoryStream stream;
+        private ODataMessageWriterSettings settings;
+        private EdmEntityType entityType;
+
+        public ODataJsonLightCollectionSerializerTests()
+        {
+            this.model = new EdmModel();
+
+            this.entityType = new EdmEntityType("NS", "Product");
+            this.entityType.AddKeys(this.entityType.AddStructuralProperty("Id", EdmPrimitiveTypeKind.Int32));
+            this.entityType.AddStructuralProperty("Name", EdmPrimitiveTypeKind.String);
+
+            this.model.AddElement(this.entityType);
+
+            this.stream = new MemoryStream();
+            this.settings = new ODataMessageWriterSettings
+            {
+                EnableMessageStreamDisposal = false,
+                Version = ODataVersion.V4
+            };
+            this.settings.SetServiceDocumentUri(new Uri("http://tempuri.org"));
+        }
+
+        [Fact]
+        public async Task WriteCollectionStartAsync_ForNonTopLevelCollection()
+        {
+            var collectionStart = new ODataCollectionStart
+            {
+                SerializationInfo = new ODataCollectionStartSerializationInfo
+                {
+                    CollectionTypeName = "Collection(String)"
+                }
+            };
+
+            var itemTypeReference = EdmCoreModel.Instance.GetString(false);
+
+            var result = await SetupODataJsonLightCollectionSerializerAndRunTestAsync(
+                (jsonLightCollectionSerializer) =>
+                {
+                    return jsonLightCollectionSerializer.WriteCollectionStartAsync(collectionStart, itemTypeReference);
+                });
+
+            Assert.Equal("[", result);
+        }
+
+        [Fact]
+        public async Task WriteCollectionEndAsync_ForNonTopLevelCollection()
+        {
+            var collectionStart = new ODataCollectionStart
+            {
+                SerializationInfo = new ODataCollectionStartSerializationInfo
+                {
+                    CollectionTypeName = "Collection(String)"
+                }
+            };
+
+            var itemTypeReference = EdmCoreModel.Instance.GetString(false);
+
+            var result = await SetupODataJsonLightCollectionSerializerAndRunTestAsync(
+                async (jsonLightCollectionSerializer) =>
+                {
+                    await jsonLightCollectionSerializer.WriteCollectionStartAsync(collectionStart, itemTypeReference);
+                    await jsonLightCollectionSerializer.WriteCollectionEndAsync();
+                });
+
+            Assert.Equal("[]", result);
+        }
+
+        [Fact]
+        public async Task WriteCollectionStartAsync_ForTopLevelCollection()
+        {
+            var collectionStart = new ODataCollectionStart
+            {
+                SerializationInfo = new ODataCollectionStartSerializationInfo
+                {
+                    CollectionTypeName = "Collection(Product)"
+                }
+            };
+
+            var itemTypeReference = new EdmEntityTypeReference(this.entityType, false);
+
+            var result = await SetupODataJsonLightCollectionSerializerAndRunTestAsync(
+                (jsonLightCollectionSerializer) =>
+                {
+                    return jsonLightCollectionSerializer.WriteCollectionStartAsync(collectionStart, itemTypeReference);
+                },
+                /* container */ null,
+                /* writeTopLevelCollection */ true);
+
+            Assert.Equal("{\"@odata.context\":\"http://tempuri.org/$metadata#Collection(Product)\",\"value\":[", result);
+        }
+
+        [Fact]
+        public async Task WriteCollectionStartAsync_ForTopLevelCollectionWithNextPageLink()
+        {
+            var collectionStart = new ODataCollectionStart
+            {
+                SerializationInfo = new ODataCollectionStartSerializationInfo
+                {
+                    CollectionTypeName = "Collection(Product)"
+                },
+                NextPageLink = new Uri("http://tempuri.org/Products?$skiptoken=Id-5")
+            };
+
+            var itemTypeReference = new EdmEntityTypeReference(this.entityType, false);
+
+            var result = await SetupODataJsonLightCollectionSerializerAndRunTestAsync(
+                (jsonLightCollectionSerializer) =>
+                {
+                    return jsonLightCollectionSerializer.WriteCollectionStartAsync(collectionStart, itemTypeReference);
+                },
+                /* container */ null,
+                /* writeTopLevelCollection */ true);
+
+            Assert.Equal(
+                "{\"@odata.context\":\"http://tempuri.org/$metadata#Collection(Product)\"," +
+                "\"@odata.nextLink\":\"http://tempuri.org/Products?$skiptoken=Id-5\"," +
+                "\"value\":[",
+                result);
+        }
+
+        [Fact]
+        public async Task WriteCollectionStartAsync_ForTopLevelCollectionWithItemCount()
+        {
+            var collectionStart = new ODataCollectionStart
+            {
+                SerializationInfo = new ODataCollectionStartSerializationInfo
+                {
+                    CollectionTypeName = "Collection(Product)"
+                },
+                Count = 10
+            };
+
+            var itemTypeReference = new EdmEntityTypeReference(this.entityType, false);
+
+            var result = await SetupODataJsonLightCollectionSerializerAndRunTestAsync(
+                (jsonLightCollectionSerializer) =>
+                {
+                    return jsonLightCollectionSerializer.WriteCollectionStartAsync(collectionStart, itemTypeReference);
+                },
+                /* container */ null,
+                /* writeTopLevelCollection */ true);
+
+            Assert.Equal(
+                "{\"@odata.context\":\"http://tempuri.org/$metadata#Collection(Product)\"," +
+                "\"@odata.count\":10," +
+                "\"value\":[",
+                result);
+        }
+
+        [Fact]
+        public async Task WriteCollectionEndAsync_ForTopLevelCollection()
+        {
+            var collectionStart = new ODataCollectionStart
+            {
+                Name = "Products",
+                SerializationInfo = new ODataCollectionStartSerializationInfo
+                {
+                    CollectionTypeName = "Collection(Product)"
+                },
+                NextPageLink = new Uri("http://tempuri.org/Products?$skiptoken=Id-5"),
+                Count = 10
+            };
+
+            var itemTypeReference = new EdmEntityTypeReference(this.entityType, false);
+
+            var result = await SetupODataJsonLightCollectionSerializerAndRunTestAsync(
+                async (jsonLightCollectionSerializer) =>
+                {
+                    await jsonLightCollectionSerializer.WriteCollectionStartAsync(collectionStart, itemTypeReference);
+                    await jsonLightCollectionSerializer.WriteCollectionEndAsync();
+                },
+                /* container */ null,
+                /* writeTopLevelCollection */ true);
+
+            Assert.Equal(
+                "{\"@odata.context\":\"http://tempuri.org/$metadata#Collection(Product)\"," +
+                "\"@odata.count\":10," +
+                "\"@odata.nextLink\":\"http://tempuri.org/Products?$skiptoken=Id-5\"," +
+                "\"value\":[]}",
+                result);
+        }
+
+        private ODataJsonLightCollectionSerializer CreateODataJsonLightCollectionSerializer(bool writingResponse, IServiceProvider container = null, bool isAsync = false, bool writingTopLevelCollection = false)
+        {
+            var messageInfo = new ODataMessageInfo
+            {
+                MessageStream = this.stream,
+                MediaType = new ODataMediaType("application", "json"),
+#if NETCOREAPP1_1
+                Encoding = Encoding.GetEncoding(0),
+#else
+                Encoding = Encoding.Default,
+#endif
+                IsResponse = writingResponse,
+                IsAsync = isAsync,
+                Model = model,
+                Container = container
+            };
+            var context = new ODataJsonLightOutputContext(messageInfo, this.settings);
+            return new ODataJsonLightCollectionSerializer(context, writingTopLevelCollection);
+        }
+
+        /// <summary>
+        /// Sets up an ODataJsonLightCollectionSerializer,
+        /// then runs the given test code asynchonously,
+        /// then flushes and reads the stream back as a string for customized verification.
+        /// </summary>
+        private async Task<string> SetupODataJsonLightCollectionSerializerAndRunTestAsync(Func<ODataJsonLightCollectionSerializer, Task> func, IServiceProvider container = null, bool writingTopLevelCollection = false)
+        {
+            var jsonLightCollectionSerializer = CreateODataJsonLightCollectionSerializer(true, container, true, writingTopLevelCollection);
+            await func(jsonLightCollectionSerializer);
+            await jsonLightCollectionSerializer.JsonLightOutputContext.FlushAsync();
+            await jsonLightCollectionSerializer.AsynchronousJsonWriter.FlushAsync();
+
+            this.stream.Position = 0;
+
+            return await new StreamReader(this.stream).ReadToEndAsync();
+        }
+    }
+}