Add extension method to simplify version selection without a HTTP request

Author: commonsensesoftware

src/AspNet/WebApi/src/Asp.Versioning.WebApi.ApiExplorer/Description/ApiVersionParameterDescriptionContext.cs

@@ -255,12 +255,7 @@ private static bool FirstParameterIsOptional(
 
         var mapping = ApiVersionMapping.Explicit | ApiVersionMapping.Implicit;
         var model = apiDescription.ActionDescriptor.GetApiVersionMetadata().Map( mapping );
-        ApiVersion defaultApiVersion;
-
-        using ( var request = new HttpRequestMessage() )
-        {
-            defaultApiVersion = options.ApiVersionSelector.SelectVersion( request, model );
-        }
+        var defaultApiVersion = options.ApiVersionSelector.SelectVersion( model );
 
         return apiVersion == defaultApiVersion;
     }

src/AspNet/WebApi/src/Asp.Versioning.WebApi/IApiVersionSelectorExtensions.cs

@@ -0,0 +1,22 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+
+namespace Asp.Versioning;
+
+/// <summary>
+/// Provides extension methods for <see cref="IApiVersionSelector"/>.
+/// </summary>
+public static class IApiVersionSelectorExtensions
+{
+    /// <summary>
+    /// Selects an API version given the specified API version information.
+    /// </summary>
+    /// <param name="selector">The extended <see cref="IApiVersionSelector"/>.</param>
+    /// <param name="model">The <see cref="ApiVersionModel">model</see> to select the version from.</param>
+    /// <returns>The selected <see cref="ApiVersion">API version</see>.</returns>
+    public static ApiVersion SelectVersion( this IApiVersionSelector selector, ApiVersionModel model )
+    {
+        ArgumentNullException.ThrowIfNull( selector );
+        using var request = new HttpRequestMessage();
+        return selector.SelectVersion( request, model );
+    }
+}

src/AspNetCore/WebApi/src/Asp.Versioning.Http/IApiVersionSelectorExtensions.cs

@@ -0,0 +1,25 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+
+namespace Asp.Versioning;
+
+using Microsoft.AspNetCore.Http;
+
+/// <summary>
+/// Provides extension methods for <see cref="IApiVersionSelector"/>.
+/// </summary>
+[CLSCompliant( false )]
+public static class IApiVersionSelectorExtensions
+{
+    /// <summary>
+    /// Selects an API version given the specified API version information.
+    /// </summary>
+    /// <param name="selector">The extended <see cref="IApiVersionSelector"/>.</param>
+    /// <param name="model">The <see cref="ApiVersionModel">model</see> to select the version from.</param>
+    /// <returns>The selected <see cref="ApiVersion">API version</see>.</returns>
+    public static ApiVersion SelectVersion( this IApiVersionSelector selector, ApiVersionModel model )
+    {
+        ArgumentNullException.ThrowIfNull( selector );
+        var context = new DefaultHttpContext();
+        return selector.SelectVersion( context.Request, model );
+    }
+}

src/AspNetCore/WebApi/src/Asp.Versioning.Mvc.ApiExplorer/ApiVersionParameterDescriptionContext.cs

@@ -453,8 +453,7 @@ private static bool FirstParameterIsOptional(
 
         var mapping = ApiVersionMapping.Explicit | ApiVersionMapping.Implicit;
         var model = apiDescription.ActionDescriptor.GetApiVersionMetadata().Map( mapping );
-        var context = new Microsoft.AspNetCore.Http.DefaultHttpContext();
-        var defaultApiVersion = options.ApiVersionSelector.SelectVersion( context.Request, model );
+        var defaultApiVersion = options.ApiVersionSelector.SelectVersion( model );
 
         return apiVersion == defaultApiVersion;
     }