Add support for alternate key parameters

src/Microsoft.OpenApi.OData.Reader/Generator/OpenApiParameterGenerator.cs

@@ -158,9 +158,9 @@ public static IList<OpenApiParameter> CreateKeyParameters(this ODataContext cont
             Utils.CheckArgumentNull(context, nameof(context));
             Utils.CheckArgumentNull(keySegment, nameof(keySegment));
 
-            IList<OpenApiParameter> parameters = new List<OpenApiParameter>();
+            List<OpenApiParameter> parameters = new();
             IEdmEntityType entityType = keySegment.EntityType;
-
+          
             IList<IEdmStructuralProperty> keys = entityType.Key().ToList();
             if (keys.Count() == 1)
             {
@@ -212,6 +212,46 @@ public static IList<OpenApiParameter> CreateKeyParameters(this ODataContext cont
                 }
             }
 
+            IList<OpenApiParameter> alternateKeyParameters = CreateAlternateKeyParameters(entityType, context);
+            parameters.AddRange(alternateKeyParameters);
+
+            return parameters;
+        }
+
+        private static IList<OpenApiParameter> CreateAlternateKeyParameters(IEdmEntityType entityType, ODataContext context)
+        {
+            IList<OpenApiParameter> parameters = new List<OpenApiParameter>();
+            IEnumerable<IDictionary<string, IEdmProperty>> alternateKeys = context.Model.GetAlternateKeysAnnotation(entityType);
+            foreach (var alternateKey in alternateKeys)
+            {
+                if (alternateKey.Count() == 1)
+                {
+                    parameters.Add(
+                        new OpenApiParameter
+                        {
+                            Name = alternateKey.First().Key,
+                            In = ParameterLocation.Path,
+                            Description = $"Alternate key: {alternateKey.First().Value.Name} of {entityType.Name}",
+                            Schema = context.CreateEdmTypeSchema(alternateKey.First().Value.Type)
+                        }
+                     );
+                }
+                else
+                {
+                    foreach (var compositekey in alternateKey)
+                    {
+                        parameters.Add(
+                            new OpenApiParameter
+                            {
+                                Name = compositekey.Key,
+                                In = ParameterLocation.Path,
+                                Description = $"Composite alternate key: {compositekey.Value.Name} of {entityType.Name}",
+                                Schema = context.CreateEdmTypeSchema(compositekey.Value.Type)
+                            }
+                        );
+                    }
+                }
+            }
             return parameters;
         }
 

src/Microsoft.OpenApi.OData.Reader/Microsoft.OpenAPI.OData.Reader.csproj

@@ -15,14 +15,15 @@
     <TargetFrameworks>netstandard2.0</TargetFrameworks>
     <PackageId>Microsoft.OpenApi.OData</PackageId>
     <SignAssembly>true</SignAssembly>
-    <Version>1.2.0-preview2</Version>
+    <Version>1.2.0-preview3</Version>
     <Description>This package contains the codes you need to convert OData CSDL to Open API Document of Model.</Description>
     <Copyright>© Microsoft Corporation. All rights reserved.</Copyright>
     <PackageTags>Microsoft OpenApi OData EDM</PackageTags>
     <RepositoryUrl>https://github.com/Microsoft/OpenAPI.NET.OData</RepositoryUrl>
     <PackageReleaseNotes>
 - Use convert setting to toggle between referencing @odata.count and @odata.nextLink #282
 - Fixes URL Path parameters of type datetime generated as strings with quotes #262
+- Add support for alternate keys #120
     </PackageReleaseNotes>
     <AssemblyName>Microsoft.OpenApi.OData.Reader</AssemblyName>
     <AssemblyOriginatorKeyFile>..\..\tool\Microsoft.OpenApi.OData.snk</AssemblyOriginatorKeyFile>

test/Microsoft.OpenAPI.OData.Reader.Tests/Generator/OpenApiParameterGeneratorTests.cs

@@ -279,6 +279,95 @@ public void CreateKeyParametersForCompositeKeyWorks(bool prefix)
             Assert.Equal(expected.ChangeLineBreaks(), json);
         }
 
+        [Fact]
+        public void CreateKeyParametersForAlternateKeyWithSinglePropertyWorks()
+        {
+            // Arrange
+            EdmModel model = new EdmModel();
+            EdmEntityType customer = new EdmEntityType("NS", "Customer");
+            customer.AddKeys(customer.AddStructuralProperty("Id", EdmPrimitiveTypeKind.String));
+
+            IEdmProperty alternateId = customer.AddStructuralProperty("AlternateId", EdmPrimitiveTypeKind.String);
+            model.AddAlternateKeyAnnotation(customer, new Dictionary<string, IEdmProperty> { { "AltId", alternateId } });
+
+            model.AddElement(customer);
+            ODataContext context = new(model);
+            ODataKeySegment keySegment = new(customer);
+
+            // Act
+            var parameters = context.CreateKeyParameters(keySegment);
+            var altParameter = parameters.Last();
+
+            // Assert
+            Assert.NotNull(parameters);
+            Assert.Equal(2, parameters.Count);
+            string json = altParameter.SerializeAsJson(OpenApiSpecVersion.OpenApi3_0);
+            Assert.Equal(@"{
+  ""name"": ""AltId"",
+  ""in"": ""path"",
+  ""description"": ""Alternate key: AlternateId of Customer"",
+  ""style"": ""simple"",
+  ""schema"": {
+    ""type"": ""string"",
+    ""nullable"": true
+  }
+}".ChangeLineBreaks(), json);
+        }
+
+         [Fact]
+        public void CreateKeyParametersForAlternateKeyWithMultiplePropertiesWorks()
+        {
+            // Arrange
+            EdmModel model = new EdmModel();
+            EdmEntityType customer = new EdmEntityType("NS", "Customer");
+            customer.AddKeys(customer.AddStructuralProperty("Id", EdmPrimitiveTypeKind.String));
+
+            IEdmProperty alternateId1 = customer.AddStructuralProperty("AlternateId1", EdmPrimitiveTypeKind.String);
+            IEdmProperty alternateId2 = customer.AddStructuralProperty("AlternateId2", EdmPrimitiveTypeKind.String);
+            model.AddAlternateKeyAnnotation(customer,
+                new Dictionary<string, IEdmProperty> 
+                { 
+                    { "AltId1", alternateId1 },
+                    { "AltId2", alternateId2 } 
+                });
+
+            model.AddElement(customer);
+            ODataContext context = new(model);
+            ODataKeySegment keySegment = new(customer);
+
+            // Act
+            var parameters = context.CreateKeyParameters(keySegment);
+            var altParameter1 = parameters.Skip(1).First();
+            var altParameter2 = parameters.Last();
+
+            // Assert
+            Assert.NotNull(parameters);
+            Assert.Equal(3, parameters.Count);
+            string json1 = altParameter1.SerializeAsJson(OpenApiSpecVersion.OpenApi3_0);
+            Assert.Equal(@"{
+  ""name"": ""AltId1"",
+  ""in"": ""path"",
+  ""description"": ""Composite alternate key: AlternateId1 of Customer"",
+  ""style"": ""simple"",
+  ""schema"": {
+    ""type"": ""string"",
+    ""nullable"": true
+  }
+}".ChangeLineBreaks(), json1);
+
+            string json2 = altParameter2.SerializeAsJson(OpenApiSpecVersion.OpenApi3_0);
+            Assert.Equal(@"{
+  ""name"": ""AltId2"",
+  ""in"": ""path"",
+  ""description"": ""Composite alternate key: AlternateId2 of Customer"",
+  ""style"": ""simple"",
+  ""schema"": {
+    ""type"": ""string"",
+    ""nullable"": true
+  }
+}".ChangeLineBreaks(), json2);
+        }
+
         [Fact]
         public void CreateOrderByAndSelectAndExpandParametersWorks()
         {