Add Metadata, segment and related path handler and operation handler, expand ODataPath to accept PathTemplate

src/Microsoft.OpenApi.OData.Reader/Common/Constants.cs

@@ -15,6 +15,11 @@ namespace Microsoft.OpenApi.OData.Common
         /// </summary>
         public static string ApplicationJsonMediaType = "application/json";
 
+        /// <summary>
+        /// application/xml
+        /// </summary>
+        public static string ApplicationXmlMediaType = "application/xml";
+
         /// <summary>
         /// application/octet-stream
         /// </summary>

src/Microsoft.OpenApi.OData.Reader/Edm/ODataDollarCountSegment.cs

@@ -0,0 +1,24 @@
+// ------------------------------------------------------------
+//  Copyright (c) Microsoft Corporation.  All rights reserved.
+//  Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
+// ------------------------------------------------------------
+
+using System.Collections.Generic;
+
+namespace Microsoft.OpenApi.OData.Edm
+{
+    /// <summary>
+    /// The $count segment.
+    /// </summary>
+    public class ODataDollarCountSegment : ODataSegment
+    {
+        /// <inheritdoc />
+        public override ODataSegmentKind Kind => ODataSegmentKind.DollarCount;
+
+        /// <inheritdoc />
+        public override string Identifier => "$count";
+
+        /// <inheritdoc />
+        public override string GetPathItemName(OpenApiConvertSettings settings, HashSet<string> parameters) => "$count";
+    }
+}

src/Microsoft.OpenApi.OData.Reader/Edm/ODataMetadataSegment.cs

@@ -0,0 +1,24 @@
+// ------------------------------------------------------------
+//  Copyright (c) Microsoft Corporation.  All rights reserved.
+//  Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
+// ------------------------------------------------------------
+
+using System.Collections.Generic;
+
+namespace Microsoft.OpenApi.OData.Edm
+{
+    /// <summary>
+    /// The $metadata segment.
+    /// </summary>
+    public class ODataMetadataSegment : ODataSegment
+    {
+        /// <inheritdoc />
+        public override ODataSegmentKind Kind => ODataSegmentKind.Metadata;
+
+        /// <inheritdoc />
+        public override string Identifier => "$metadata";
+
+        /// <inheritdoc />
+        public override string GetPathItemName(OpenApiConvertSettings settings, HashSet<string> parameters) => "$metadata";
+    }
+}

src/Microsoft.OpenApi.OData.Reader/Edm/ODataPath.cs

@@ -45,6 +45,17 @@ namespace Microsoft.OpenApi.OData.Edm
         {
         }
 
+        /// <summary>
+        /// Gets/Sets the support HttpMethods
+        /// </summary>
+        public ISet<string> HttpMethods { get; } = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+
+        /// <summary>
+        /// Gets/Sets the path template for this path.
+        /// If it is set, it will be used to generate the path item.
+        /// </summary>
+        public string PathTemplate { get; set; }
+
         /// <summary>
         /// Gets the segments.
         /// </summary>
@@ -176,6 +187,17 @@ namespace Microsoft.OpenApi.OData.Edm
             return sb.ToString();
         }
 
+        internal bool SupportHttpMethod(string method)
+        {
+            // If the Httpmethods is empty, let it go
+            if (HttpMethods.Count == 0)
+            {
+                return true;
+            }
+
+            return HttpMethods.Contains(method);
+        }
+
         /// <summary>
         /// Push a segment to the last.
         /// </summary>
@@ -243,6 +265,11 @@ namespace Microsoft.OpenApi.OData.Edm
         /// <returns>The string.</returns>
         public override string ToString()
         {
+            if (PathTemplate != null)
+            {
+                return PathTemplate;
+            }
+
             return "/" + String.Join("/", Segments.Select(e => e.Kind));
         }
 
@@ -258,6 +285,16 @@ namespace Microsoft.OpenApi.OData.Edm
 
         private ODataPathKind CalcPathType()
         {
+            if (Segments.Count == 1 && Segments.First().Kind == ODataSegmentKind.Metadata)
+            {
+                return ODataPathKind.Metadata;
+            }
+
+            if (Segments.Last().Kind == ODataSegmentKind.DollarCount)
+            {
+                return ODataPathKind.DollarCount;
+            }
+
             if (Segments.Any(c => c.Kind == ODataSegmentKind.StreamProperty || c.Kind == ODataSegmentKind.StreamContent))
             {
                 return ODataPathKind.MediaEntity;

src/Microsoft.OpenApi.OData.Reader/Edm/ODataPathKind.cs

@@ -50,6 +50,16 @@ namespace Microsoft.OpenApi.OData.Edm
         /// </summary>
         MediaEntity,
 
+        /// <summary>
+        /// Represents a $metadata path
+        /// </summary>
+        Metadata,
+
+        /// <summary>
+        /// Represents a $count path, for example: ~/customers/$count
+        /// </summary>
+        DollarCount,
+
         /// <summary>
         /// Represents an un-supported/unknown path.
         /// </summary>

src/Microsoft.OpenApi.OData.Reader/Edm/ODataSegment.cs

@@ -6,6 +6,7 @@
 using System;
 using System.Collections.Generic;
 using Microsoft.OData.Edm;
+using Microsoft.OpenApi.Models;
 
 namespace Microsoft.OpenApi.OData.Edm
 {
@@ -14,6 +15,11 @@ namespace Microsoft.OpenApi.OData.Edm
     /// </summary>
     public enum ODataSegmentKind
     {
+        /// <summary>
+        /// $metadata
+        /// </summary>
+        Metadata,
+
         /// <summary>
         /// Navigation source (entity set or singleton )
         /// </summary>
@@ -57,7 +63,12 @@ namespace Microsoft.OpenApi.OData.Edm
         /// <summary>
         /// Stream property
         /// </summary>
-        StreamProperty
+        StreamProperty,
+
+        /// <summary>
+        /// $count
+        /// </summary>
+        DollarCount,
     }
 
     /// <summary>

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

@@ -42,7 +42,14 @@ namespace Microsoft.OpenApi.OData.Generator
                     continue;
                 }
 
-                pathItems.Add(path.GetPathItemName(settings), handler.CreatePathItem(context, path));
+                if (path.PathTemplate != null)
+                {
+                    pathItems.Add(path.PathTemplate, handler.CreatePathItem(context, path));
+                }
+                else
+                {
+                    pathItems.Add(path.GetPathItemName(settings), handler.CreatePathItem(context, path));
+                }
             }
 
             if (settings.ShowRootPath)

src/Microsoft.OpenApi.OData.Reader/Operation/DollarCountGetOperationHandler.cs

@@ -0,0 +1,88 @@
+// ------------------------------------------------------------
+//  Copyright (c) Microsoft Corporation.  All rights reserved.
+//  Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
+// ------------------------------------------------------------
+
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.OpenApi.Models;
+using Microsoft.OpenApi.OData.Common;
+using Microsoft.OpenApi.OData.Edm;
+using Microsoft.OpenApi.OData.Generator;
+
+namespace Microsoft.OpenApi.OData.Operation
+{
+    /// <summary>
+    /// Retrieve a $count get
+    /// </summary>
+    internal class DollarCountGetOperationHandler : OperationHandler
+    {
+        /// <inheritdoc/>
+        public override OperationType OperationType => OperationType.Get;
+
+        /// <summary>
+        /// Gets/sets the segment before $count.
+        /// this segment could be "entity set", "Collection property", "Composable function whose return is collection",etc.
+        /// </summary>
+        internal ODataSegment LastSecondSegment { get; set; }
+
+        /// <inheritdoc/>
+        protected override void Initialize(ODataContext context, ODataPath path)
+        {
+            base.Initialize(context, path);
+
+            // get the last second segment
+            int count = path.Segments.Count;
+            LastSecondSegment = path.Segments.ElementAt(count - 1);
+        }
+
+        /// <inheritdoc/>
+        protected override void SetBasicInfo(OpenApiOperation operation)
+        {
+            // Summary
+            operation.Summary = $"Get the number of the resource";
+
+            // OperationId
+            if (Context.Settings.EnableOperationId)
+            {
+                operation.OperationId = $"Get.Count.{LastSecondSegment.Identifier}";
+            }
+
+            base.SetBasicInfo(operation);
+        }
+
+        /// <inheritdoc/>
+        protected override void SetResponses(OpenApiOperation operation)
+        {
+            OpenApiSchema schema = new OpenApiSchema
+            {
+                Type = "integer",
+                Format = "int32"
+            };
+
+            operation.Responses = new OpenApiResponses
+            {
+                {
+                    Constants.StatusCode200,
+                    new OpenApiResponse
+                    {
+                        Description = "The count of the resource",
+                        Content = new Dictionary<string, OpenApiMediaType>
+                        {
+                            {
+                                "text/plain",
+                                new OpenApiMediaType
+                                {
+                                    Schema = schema
+                                }
+                            }
+                        }
+                    }
+                }
+            };
+            operation.Responses.Add(Constants.StatusCodeDefault, Constants.StatusCodeDefault.GetResponse());
+
+            base.SetResponses(operation);
+        }
+    }
+}

src/Microsoft.OpenApi.OData.Reader/Operation/MediaEntityGetOperationHandler.cs

@@ -63,6 +63,7 @@ namespace Microsoft.OpenApi.OData.Operation
 
             base.SetResponses(operation);
         }
+
         /// <inheritdoc/>
         protected override void SetSecurity(OpenApiOperation operation)
         {

src/Microsoft.OpenApi.OData.Reader/Operation/MetadataGetOperationHandler.cs

@@ -0,0 +1,77 @@
+// ------------------------------------------------------------
+//  Copyright (c) Microsoft Corporation.  All rights reserved.
+//  Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
+// ------------------------------------------------------------
+
+using System.Collections.Generic;
+using Microsoft.OpenApi.Models;
+using Microsoft.OpenApi.OData.Common;
+using Microsoft.OpenApi.OData.Generator;
+
+namespace Microsoft.OpenApi.OData.Operation
+{
+    /// <summary>
+    /// Retrieve a metadata document "get"
+    /// </summary>
+    internal class MetadataGetOperationHandler : OperationHandler
+    {
+        /// <inheritdoc/>
+        public override OperationType OperationType => OperationType.Get;
+
+        /// <inheritdoc/>
+        protected override void SetBasicInfo(OpenApiOperation operation)
+        {
+            // Summary
+            operation.Summary = $"Get OData metadata (CSDL) document";
+
+            // OperationId
+            if (Context.Settings.EnableOperationId)
+            {
+                string routePrefix = Context.Settings.PathPrefix ?? "";
+                if (Context.Settings.PathPrefix != null)
+                {
+                    operation.OperationId = $"{routePrefix}.Get.Metadata";
+                }
+                else
+                {
+                    operation.OperationId = "Get.Metadata";
+                }
+            }
+
+            base.SetBasicInfo(operation);
+        }
+
+        /// <inheritdoc/>
+        protected override void SetResponses(OpenApiOperation operation)
+        {
+            OpenApiSchema schema = new OpenApiSchema
+            {
+                Type = "string"
+            };
+
+            operation.Responses = new OpenApiResponses
+            {
+                {
+                    Constants.StatusCode200,
+                    new OpenApiResponse
+                    {
+                        Description = "Retrieved metadata document",
+                        Content = new Dictionary<string, OpenApiMediaType>
+                        {
+                            {
+                                Constants.ApplicationXmlMediaType,
+                                new OpenApiMediaType
+                                {
+                                    Schema = schema
+                                }
+                            }
+                        }
+                    }
+                }
+            };
+            operation.Responses.Add(Constants.StatusCodeDefault, Constants.StatusCodeDefault.GetResponse());
+
+            base.SetResponses(operation);
+        }
+    }
+}

src/Microsoft.OpenApi.OData.Reader/Operation/OperationHandlerProvider.cs

@@ -83,6 +83,18 @@ namespace Microsoft.OpenApi.OData.Operation
                 {OperationType.Get, new MediaEntityGetOperationHandler() },
                 {OperationType.Put, new MediaEntityPutOperationHandler() }
             };
+
+            // $metadata operation (Get)
+            _handlers[ODataPathKind.Metadata] = new Dictionary<OperationType, IOperationHandler>
+            {
+                {OperationType.Get, new MetadataGetOperationHandler() }
+            };
+
+            // $count operation (Get)
+            _handlers[ODataPathKind.DollarCount] = new Dictionary<OperationType, IOperationHandler>
+            {
+                {OperationType.Get, new DollarCountGetOperationHandler() }
+            };
         }
 
         /// <inheritdoc/>

src/Microsoft.OpenApi.OData.Reader/PathItem/DollarCountPathItemHandler.cs

@@ -0,0 +1,25 @@
+// ------------------------------------------------------------
+//  Copyright (c) Microsoft Corporation.  All rights reserved.
+//  Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
+// ------------------------------------------------------------
+
+using Microsoft.OpenApi.Models;
+using Microsoft.OpenApi.OData.Edm;
+
+namespace Microsoft.OpenApi.OData.PathItem
+{
+    /// <summary>
+    /// Path item handler for $count.
+    /// </summary>
+    internal class DollarCountPathItemHandler : PathItemHandler
+    {
+        /// <inheritdoc/>
+        protected override ODataPathKind HandleKind => ODataPathKind.DollarCount;
+
+        /// <inheritdoc/>
+        protected override void SetOperations(OpenApiPathItem item)
+        {
+            AddOperation(item, OperationType.Get);
+        }
+    }
+}

src/Microsoft.OpenApi.OData.Reader/PathItem/MetadataPathItemHandler.cs

@@ -0,0 +1,25 @@
+// ------------------------------------------------------------
+//  Copyright (c) Microsoft Corporation.  All rights reserved.
+//  Licensed under the MIT License (MIT). See LICENSE in the repo root for license information.
+// ------------------------------------------------------------
+
+using Microsoft.OpenApi.Models;
+using Microsoft.OpenApi.OData.Edm;
+
+namespace Microsoft.OpenApi.OData.PathItem
+{
+    /// <summary>
+    /// Path item handler for $metadata.
+    /// </summary>
+    internal class MetadataPathItemHandler : PathItemHandler
+    {
+        /// <inheritdoc/>
+        protected override ODataPathKind HandleKind => ODataPathKind.Metadata;
+
+        /// <inheritdoc/>
+        protected override void SetOperations(OpenApiPathItem item)
+        {
+            AddOperation(item, OperationType.Get);
+        }
+    }
+}

src/Microsoft.OpenApi.OData.Reader/PathItem/PathItemHandler.cs

@@ -83,6 +83,12 @@ namespace Microsoft.OpenApi.OData.PathItem
         /// <param name="operationType">The operation type.</param>
         protected virtual void AddOperation(OpenApiPathItem item, OperationType operationType)
         {
+            string httpMethod = operationType.ToString();
+            if (!Path.SupportHttpMethod(httpMethod))
+            {
+                return;
+            }
+
             IOperationHandlerProvider provider = Context.OperationHanderProvider;
             IOperationHandler operationHander = provider.GetHandler(Path.Kind, operationType);
             item.AddOperation(operationType, operationHander.CreateOperation(Context, Path));

src/Microsoft.OpenApi.OData.Reader/PathItem/PathItemHandlerProvider.cs

@@ -37,7 +37,13 @@ namespace Microsoft.OpenApi.OData.PathItem
             { ODataPathKind.Ref, new RefPathItemHandler() },
 
             // Media Entity
-            {ODataPathKind.MediaEntity, new MediaEntityPathItemHandler() },
+            { ODataPathKind.MediaEntity, new MediaEntityPathItemHandler() },
+
+            // $Metadata
+            { ODataPathKind.Metadata, new MetadataPathItemHandler() },
+
+            // $count
+            { ODataPathKind.DollarCount, new DollarCountPathItemHandler() },
 
             // Unknown
             { ODataPathKind.Unknown, null },

test/Microsoft.OpenAPI.OData.Reader.Tests/Operation/OperationHandlerProviderTests.cs

@@ -34,6 +34,8 @@ namespace Microsoft.OpenApi.OData.Operation.Tests
         [InlineData(ODataPathKind.Ref, OperationType.Put, typeof(RefPutOperationHandler))]
         [InlineData(ODataPathKind.MediaEntity, OperationType.Get, typeof(MediaEntityGetOperationHandler))]
         [InlineData(ODataPathKind.MediaEntity, OperationType.Put, typeof(MediaEntityPutOperationHandler))]
+        [InlineData(ODataPathKind.Metadata, OperationType.Get, typeof(MetadataGetOperationHandler))]
+        [InlineData(ODataPathKind.DollarCount, OperationType.Get, typeof(DollarCountGetOperationHandler))]
         public void GetHandlerReturnsCorrectOperationHandlerType(ODataPathKind pathKind, OperationType operationType, Type handlerType)
         {
             // Arrange

test/Microsoft.OpenAPI.OData.Reader.Tests/PathItem/PathItemHandlerProviderTests.cs

@@ -20,6 +20,8 @@ namespace Microsoft.OpenApi.OData.PathItem.Tests
         [InlineData(ODataPathKind.OperationImport, typeof(OperationImportPathItemHandler))]
         [InlineData(ODataPathKind.Ref, typeof(RefPathItemHandler))]
         [InlineData(ODataPathKind.MediaEntity, typeof(MediaEntityPathItemHandler))]
+        [InlineData(ODataPathKind.Metadata, typeof(MetadataPathItemHandler))]
+        [InlineData(ODataPathKind.DollarCount, typeof(DollarCountPathItemHandler))]
         public void GetHandlerReturnsCorrectHandlerType(ODataPathKind pathKind, Type handlerType)
         {
             // Arrange