Support writing nested entities without a navigation source. (#996)

* Support writing nested entities without a navigation source.

* Added Tests

* Apply suggested improvements for disposing resources in tests.

Author: mikepizzo

src/Microsoft.AspNetCore.OData/Formatter/Serialization/ODataResourceSerializer.cs

@@ -1179,22 +1179,25 @@ public virtual ODataNestedResourceInfo CreateNavigationLink(IEdmNavigationProper
             IEdmNavigationSource navigationSource = writeContext.NavigationSource;
             ODataNestedResourceInfo navigationLink = null;
 
-            if (navigationSource != null && navigationProperty.Type != null)
+            if (navigationProperty.Type != null)
             {
                 IEdmTypeReference propertyType = navigationProperty.Type;
-                IEdmModel model = writeContext.Model;
-                NavigationSourceLinkBuilderAnnotation linkBuilder = EdmModelLinkBuilderExtensions.GetNavigationSourceLinkBuilder(model, navigationSource);
-                Uri navigationUrl = linkBuilder.BuildNavigationLink(resourceContext, navigationProperty, writeContext.MetadataLevel);
-
                 navigationLink = new ODataNestedResourceInfo
                 {
                     IsCollection = propertyType.IsCollection(),
                     Name = navigationProperty.Name,
                 };
 
-                if (navigationUrl != null)
+                if (navigationSource != null)
                 {
-                    navigationLink.Url = navigationUrl;
+                    IEdmModel model = writeContext.Model;
+                    NavigationSourceLinkBuilderAnnotation linkBuilder = EdmModelLinkBuilderExtensions.GetNavigationSourceLinkBuilder(model, navigationSource);
+                    Uri navigationUrl = linkBuilder.BuildNavigationLink(resourceContext, navigationProperty, writeContext.MetadataLevel);
+
+                    if (navigationUrl != null)
+                    {
+                        navigationLink.Url = navigationUrl;
+                    }
                 }
             }
 

test/Microsoft.AspNetCore.OData.Tests/Formatter/Serialization/ODataResourceSerializerTests.cs

@@ -7,7 +7,10 @@
 
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
+using System.Reflection.Metadata;
+using System.Runtime.CompilerServices;
 using System.Runtime.Serialization;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.OData.Abstracts;
@@ -20,6 +23,7 @@
 using Microsoft.AspNetCore.OData.Tests.Edm;
 using Microsoft.AspNetCore.OData.Tests.Extensions;
 using Microsoft.AspNetCore.OData.Tests.Models;
+using Microsoft.AspNetCore.Rewrite;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Net.Http.Headers;
 using Microsoft.OData;
@@ -2249,6 +2253,78 @@ public async Task WriteObjectInlineAsync_SetsParentContext_ForExpandedNavigation
                     It.Is<ODataSerializerContext>(c => c.ExpandedResource.SerializerContext == _writeContext)));
         }
 
+        [Fact]
+        public async Task WriteObjectInlineAsync_Writes_Nested_Entities_Without_NavigationSource()
+        {
+            // Arrange
+            ODataModelBuilder builder = new ODataConventionModelBuilder();
+            builder.Namespace = "Default";
+            builder.EntityType<Product>();
+            builder.ComplexType<Result>();
+            var model = builder.GetEdmModel();
+
+            var result = new Result
+            {
+                Title = "myResult",
+                Products = new Product[]
+                {
+                    new Product
+                    {
+                        ProductID = 1
+                    },
+                    new Product
+                    {
+                        ProductID = 2
+                    }
+                }
+            };
+
+            var resultType = model.FindType("Default.Result") as IEdmComplexType;
+            var resultTypeReference = new EdmComplexTypeReference(resultType as IEdmComplexType, false);
+            var titleProperty = resultTypeReference.FindProperty("Title") as IEdmStructuralProperty;
+            var productsProperty = resultTypeReference.FindNavigationProperty("Products");
+            var selectExpand = new SelectExpandClause(new SelectItem[]
+                {
+                    new PathSelectItem(new ODataSelectPath(new PropertySegment(titleProperty))),
+                    new ExpandedNavigationSelectItem(new ODataExpandPath(new NavigationPropertySegment(productsProperty, null)),null,null)
+                },
+             false);
+
+            var writeContext = new ODataSerializerContext()
+            {
+                Model = model,
+                SelectExpandClause = selectExpand
+            };
+
+            using (var stream = new MemoryStream())
+            {
+                IODataResponseMessage responseMessage = new ODataMessageWrapper(stream);
+                ODataUri uri = new ODataUri { ServiceRoot = new Uri("http://myService", UriKind.Absolute) };
+                ODataMessageWriterSettings settings = new ODataMessageWriterSettings
+                {
+                    ODataUri = uri
+                };
+
+                using (ODataMessageWriter messageWriter = new ODataMessageWriter(responseMessage, settings))
+                {
+                    ODataWriter writer = await messageWriter.CreateODataResourceWriterAsync(null, resultType as IEdmComplexType);
+                    ODataResourceSerializer serializer = new ODataResourceSerializer(_serializerProvider);
+
+                    // Act
+                    await serializer.WriteObjectInlineAsync(result, resultTypeReference, writer, writeContext);
+
+                    // Assert
+                    stream.Position = 0;
+                    using (StreamReader reader = new StreamReader(stream))
+                    {
+                        string response = reader.ReadToEnd();
+                        Assert.Contains(@"""ProductID"":1", response);
+                        Assert.Contains(@"""ProductID"":2", response);
+                    }
+                }
+            }
+        }
+
         [Fact]
         public void CreateSelectExpandNode_Caches_SelectExpandNode()
         {
@@ -2487,6 +2563,12 @@ private class Order
             public Customer Customer { get; set; }
         }
 
+        private class Result
+        {
+            public string Title { get; set; }
+            public IList<Product> Products { get; set; }
+        }
+
         private class SpecialOrder
         {
             public SpecialCustomer SpecialCustomer { get; set; }