support IAsyncenumerable

src/Microsoft.AspNetCore.OData/Common/TypeHelper.cs

@@ -240,7 +240,8 @@ Type collectionInterface
                     .Union(new[] { clrType })
                     .FirstOrDefault(
                         t => t.IsGenericType
-                             && t.GetGenericTypeDefinition() == typeof(IEnumerable<>));
+                             && (t.GetGenericTypeDefinition() == typeof(IEnumerable<>)
+                             || t.GetGenericTypeDefinition() == typeof(IAsyncEnumerable<>)));
 
             if (collectionInterface != null)
             {

src/Microsoft.AspNetCore.OData/Edm/DefaultODataTypeMapper.cs

@@ -222,9 +222,20 @@ private IEdmType GetEdmType(IEdmModel edmModel, Type clrType, bool testCollectio
                     }
 
                     Type enumerableOfT = ExtractGenericInterface(clrType, typeof(IEnumerable<>));
-                    if (enumerableOfT != null)
+                    Type asyncEnumerableOfT = ExtractGenericInterface(clrType, typeof(IAsyncEnumerable<>));
+
+                    if (enumerableOfT != null || asyncEnumerableOfT != null)
                     {
-                        Type elementClrType = enumerableOfT.GetGenericArguments()[0];
+                        Type elementClrType = null;
+
+                        if (enumerableOfT != null)
+                        {
+                            elementClrType = enumerableOfT.GetGenericArguments()[0];
+                        }
+                        else
+                        {
+                            elementClrType = asyncEnumerableOfT.GetGenericArguments()[0];
+                        }
 
                         // IEnumerable<SelectExpandWrapper<T>> is a collection of T.
                         if (elementClrType.IsSelectExpandWrapper(out entityType))

src/Microsoft.AspNetCore.OData/Formatter/ResourceSetContext.cs

@@ -6,6 +6,7 @@
 //------------------------------------------------------------------------------
 
 using System.Collections;
+using System.Collections.Generic;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.OData.Extensions;
 using Microsoft.AspNetCore.OData.Formatter.Serialization;
@@ -55,11 +56,27 @@ internal static ResourceSetContext Create(ODataSerializerContext writeContext, I
             {
                 Request = writeContext.Request,
                 EntitySetBase = writeContext.NavigationSource as IEdmEntitySetBase,
-              //  Url = writeContext.Url,
                 ResourceSetInstance = resourceSetInstance
             };
 
             return resourceSetContext;
         }
+
+        /// <summary>
+        /// Create a <see cref="ResourceSetContext"/> from an <see cref="ODataSerializerContext"/> and <see cref="IAsyncEnumerable{T}"/>.
+        /// </summary>
+        /// <param name="writeContext">The serializer context.</param>
+        /// <param name="resourceSetInstance">The instance representing the resourceSet being written.</param>
+        /// <returns>A new <see cref="ResourceSetContext"/>.</returns>
+        /// <remarks>This signature uses types that are AspNetCore-specific.</remarks>
+        internal static ResourceSetContext Create(ODataSerializerContext writeContext, IAsyncEnumerable<object> resourceSetInstance)
+        {
+            return new ResourceSetContext
+            {
+                Request = writeContext.Request,
+                EntitySetBase = writeContext.NavigationSource as IEdmEntitySetBase,
+                ResourceSetInstance = resourceSetInstance
+            };
+        }
     }
 }

src/Microsoft.AspNetCore.OData/Microsoft.AspNetCore.OData.xml

@@ -4309,6 +4309,15 @@
             <returns>A new <see cref="T:Microsoft.AspNetCore.OData.Formatter.ResourceSetContext"/>.</returns>
             <remarks>This signature uses types that are AspNetCore-specific.</remarks>
         </member>
+        <member name="M:Microsoft.AspNetCore.OData.Formatter.ResourceSetContext.Create(Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext,System.Collections.Generic.IAsyncEnumerable{System.Object})">
+            <summary>
+            Create a <see cref="T:Microsoft.AspNetCore.OData.Formatter.ResourceSetContext"/> from an <see cref="T:Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext"/> and <see cref="T:System.Collections.Generic.IAsyncEnumerable`1"/>.
+            </summary>
+            <param name="writeContext">The serializer context.</param>
+            <param name="resourceSetInstance">The instance representing the resourceSet being written.</param>
+            <returns>A new <see cref="T:Microsoft.AspNetCore.OData.Formatter.ResourceSetContext"/>.</returns>
+            <remarks>This signature uses types that are AspNetCore-specific.</remarks>
+        </member>
         <member name="T:Microsoft.AspNetCore.OData.Formatter.Serialization.IODataEdmTypeSerializer">
             <summary>
             Represents an <see cref="T:Microsoft.AspNetCore.OData.Formatter.Serialization.IODataSerializer"/> that serializes instances of objects backed by an <see cref="T:Microsoft.OData.Edm.IEdmType"/>.
@@ -4914,6 +4923,15 @@
             <param name="writeContext">The serializer context.</param>
             <returns>The created <see cref="T:Microsoft.OData.ODataResourceSet"/> object.</returns>
         </member>
+        <member name="M:Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSetSerializer.CreateResourceSet(System.Collections.Generic.IAsyncEnumerable{System.Object},Microsoft.OData.Edm.IEdmCollectionTypeReference,Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext)">
+            <summary>
+            Create the <see cref="T:Microsoft.OData.ODataResourceSet"/> to be written for the given resourceSet instance.
+            </summary>
+            <param name="resourceSetInstance">The instance representing the resourceSet being written.</param>
+            <param name="resourceSetType">The EDM type of the resourceSet being written.</param>
+            <param name="writeContext">The serializer context.</param>
+            <returns>The created <see cref="T:Microsoft.OData.ODataResourceSet"/> object.</returns>
+        </member>
         <member name="M:Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSetSerializer.GetNextLinkGenerator(Microsoft.OData.ODataResourceSetBase,System.Collections.IEnumerable,Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext)">
             <summary>
             Creates a function that takes in an object and generates nextlink uri.
@@ -4923,6 +4941,15 @@
             <param name="writeContext">The serializer context.</param>
             <returns>The function that generates the NextLink from an object.</returns>
         </member>
+        <member name="M:Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSetSerializer.GetNextLinkGenerator(Microsoft.OData.ODataResourceSetBase,System.Collections.Generic.IAsyncEnumerable{System.Object},Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext)">
+            <summary>
+            Creates a function that takes in an object and generates a nextlink uri.
+            </summary>
+            <param name="resourceSet">The resource set describing a collection of structured objects.</param>
+            <param name="resourceSetInstance">The instance representing the resourceSet being written.</param>
+            <param name="writeContext">The serializer context.</param>
+            <returns>The function that generates the NextLink from an object.</returns>
+        </member>
         <member name="M:Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSetSerializer.CreateODataOperation(Microsoft.OData.Edm.IEdmOperation,Microsoft.AspNetCore.OData.Formatter.ResourceSetContext,Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext)">
             <summary>
              Creates an <see cref="T:Microsoft.OData.ODataOperation" /> to be written for the given operation and the resourceSet instance.

src/Microsoft.AspNetCore.OData/PublicAPI.Unshipped.txt

@@ -1842,6 +1842,7 @@ virtual Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSerializ
 virtual Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSerializer.CreateUntypedPropertyValue(Microsoft.OData.Edm.IEdmStructuralProperty structuralProperty, Microsoft.AspNetCore.OData.Formatter.ResourceContext resourceContext, out Microsoft.OData.Edm.IEdmTypeReference actualType) -> object
 virtual Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSerializer.WriteDeltaObjectInlineAsync(object graph, Microsoft.OData.Edm.IEdmTypeReference expectedType, Microsoft.OData.ODataWriter writer, Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext writeContext) -> System.Threading.Tasks.Task
 virtual Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSetSerializer.CreateODataOperation(Microsoft.OData.Edm.IEdmOperation operation, Microsoft.AspNetCore.OData.Formatter.ResourceSetContext resourceSetContext, Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext writeContext) -> Microsoft.OData.ODataOperation
+virtual Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSetSerializer.CreateResourceSet(System.Collections.Generic.IAsyncEnumerable<object> resourceSetInstance, Microsoft.OData.Edm.IEdmCollectionTypeReference resourceSetType, Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext writeContext) -> Microsoft.OData.ODataResourceSet
 virtual Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSetSerializer.CreateResourceSet(System.Collections.IEnumerable resourceSetInstance, Microsoft.OData.Edm.IEdmCollectionTypeReference resourceSetType, Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext writeContext) -> Microsoft.OData.ODataResourceSet
 virtual Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSetSerializer.WriteEnumItemAsync(object enumValue, Microsoft.OData.Edm.IEdmTypeReference enumType, Microsoft.OData.Edm.IEdmTypeReference parentSetType, Microsoft.OData.ODataWriter writer, Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext writeContext) -> System.Threading.Tasks.Task
 virtual Microsoft.AspNetCore.OData.Formatter.Serialization.ODataResourceSetSerializer.WritePrimitiveItemAsync(object primitiveValue, Microsoft.OData.Edm.IEdmTypeReference primitiveType, Microsoft.OData.Edm.IEdmTypeReference parentSetType, Microsoft.OData.ODataWriter writer, Microsoft.AspNetCore.OData.Formatter.Serialization.ODataSerializerContext writeContext) -> System.Threading.Tasks.Task

test/Microsoft.AspNetCore.OData.E2E.Tests/IAsyncEnumerableTests/IAsyncEnumerableController.cs

@@ -0,0 +1,128 @@
+//-----------------------------------------------------------------------------
+// <copyright file="IAsyncEnumerableController.cs" company=".NET Foundation">
+//      Copyright (c) .NET Foundation and Contributors. All rights reserved.
+//      See License.txt in the project root for license information.
+// </copyright>
+//------------------------------------------------------------------------------
+
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.OData.Query;
+using Microsoft.AspNetCore.OData.Routing.Controllers;
+
+namespace Microsoft.AspNetCore.OData.E2E.Tests.IAsyncEnumerableTests
+{
+    public class CustomersController : ODataController
+    {
+        private readonly IAsyncEnumerableContext _context;
+
+        public CustomersController(IAsyncEnumerableContext context)
+        {
+            context.Database.EnsureCreated();
+            _context = context;
+
+            if (!_context.Customers.Any())
+            {
+                Generate();
+            }
+        }
+
+        [EnableQuery]
+        [HttpGet("v1/Customers")]
+        public IAsyncEnumerable<Customer> CustomersData()
+        {
+            IAsyncEnumerable<Customer> customers = CreateCollectionAsync<Customer>();
+
+            return customers;
+        }
+
+        [EnableQuery]
+        [HttpGet("odata/Customers")]
+        public IAsyncEnumerable<Customer> Get()
+        {
+            return _context.Customers.AsAsyncEnumerable();
+        }
+
+        public async IAsyncEnumerable<Customer> CreateCollectionAsync<T>()
+        {
+            await Task.Delay(5);
+            // Yield the items one by one asynchronously
+            yield return new Customer
+            {
+                Id = 1,
+                Name = "Customer1",
+                Orders = new List<Order> {
+                    new Order {
+                        Name = "Order1",
+                        Price = 25
+                    },
+                    new Order {
+                         Name = "Order2",
+                         Price = 75
+                    }
+                },
+                Address = new Address
+                {
+                    Name = "City1",
+                    Street = "Street1"
+                }
+            };
+
+            await Task.Delay(5);
+
+            yield return new Customer
+            {
+                Id = 2,
+                Name = "Customer2",
+                Orders = new List<Order> {
+                    new Order {
+                        Name = "Order1",
+                        Price = 35
+                    },
+                    new Order {
+                         Name = "Order2",
+                         Price = 65
+                    }
+                },
+                Address = new Address
+                {
+                    Name = "City2",
+                    Street = "Street2"
+                }
+            };
+        }
+
+        public void Generate()
+        {
+            for (int i = 1; i <= 3; i++)
+            {
+                var customer = new Customer
+                {
+                    Name = "Customer" + (i + 1) % 2,
+                    Orders =
+                        new List<Order> {
+                            new Order {
+                                Name = "Order" + 2*i,
+                                Price = i * 25  
+                            },
+                            new Order {
+                                Name = "Order" + 2*i+1,
+                                Price = i * 75
+                            }
+                        },
+                    Address = new Address
+                    {
+                        Name = "City" + i % 2,
+                        Street = "Street" + i % 2,
+                    }
+                };
+
+                _context.Customers.Add(customer);
+            }
+
+            _context.SaveChanges();
+        }
+    }
+}

test/Microsoft.AspNetCore.OData.E2E.Tests/IAsyncEnumerableTests/IAsyncEnumerableDataModel.cs

@@ -0,0 +1,54 @@
+//-----------------------------------------------------------------------------
+// <copyright file="IAsyncEnumerableDataModel.cs" company=".NET Foundation">
+//      Copyright (c) .NET Foundation and Contributors. All rights reserved.
+//      See License.txt in the project root for license information.
+// </copyright>
+//------------------------------------------------------------------------------
+
+using System.Collections.Generic;
+using Microsoft.EntityFrameworkCore;
+
+namespace Microsoft.AspNetCore.OData.E2E.Tests.IAsyncEnumerableTests
+{
+    public class IAsyncEnumerableContext : DbContext
+    {
+        public IAsyncEnumerableContext(DbContextOptions<IAsyncEnumerableContext> options)
+            : base(options)
+        {
+        }
+
+        public DbSet<Customer> Customers { get; set; }
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            modelBuilder.Entity<Customer>().OwnsOne(c => c.Address).WithOwner();
+        }
+    }
+
+    public class Customer
+    {
+        public int Id { get; set; }
+
+        public string Name { get; set; }
+
+        public Address Address { get; set; }
+
+        public IList<Order> Orders { get; set; }
+    }
+
+    public class Order
+    {
+        public int Id { get; set; }
+
+        public string Name { get; set; }
+
+        public int Price { get; set; }
+    }
+
+    public class Address
+    {
+        public string Name { get; set; }
+
+        public string Street { get; set; }
+    }
+}

test/Microsoft.AspNetCore.OData.E2E.Tests/IAsyncEnumerableTests/IAsyncEnumerableEdmModel.cs

@@ -0,0 +1,24 @@
+//-----------------------------------------------------------------------------
+// <copyright file="IAsyncEnumerableEdmModel.cs" company=".NET Foundation">
+//      Copyright (c) .NET Foundation and Contributors. All rights reserved.
+//      See License.txt in the project root for license information.
+// </copyright>
+//------------------------------------------------------------------------------
+
+using Microsoft.OData.Edm;
+using Microsoft.OData.ModelBuilder;
+
+namespace Microsoft.AspNetCore.OData.E2E.Tests.IAsyncEnumerableTests
+{
+    public class IAsyncEnumerableEdmModel
+    {
+        public static IEdmModel GetEdmModel()
+        {
+            var builder = new ODataConventionModelBuilder();
+            builder.EntitySet<Customer>("Customers");
+            builder.EntitySet<Order>("Orders");
+            IEdmModel model = builder.GetEdmModel();
+            return model;
+        }
+    }
+}