Add extension method to initialize IApiVersioningFeature on demand. Fixes #704

Author: commonsensesoftware

src/Microsoft.AspNetCore.Mvc.Versioning/HttpContextExtensions.cs

@@ -11,22 +11,36 @@
     public static class HttpContextExtensions
     {
         /// <summary>
-        /// Gets the current API version requested.
+        /// Gets the API versioning feature associated with the current HTTP context.
         /// </summary>
-        /// <param name="context">The current <see cref="HttpContext">HTTP context</see> to get the API version for.</param>
-        /// <returns>The requested <see cref="ApiVersion">API version</see> or <c>null</c>.</returns>
-        /// <remarks>This method will return <c>null</c> no service API version was requested or the requested
-        /// service API version is in an invalid format.</remarks>
-        /// <exception cref="AmbiguousApiVersionException">Multiple, different API versions were requested.</exception>
-        public static ApiVersion? GetRequestedApiVersion( this HttpContext context )
+        /// <param name="context">The current <see cref="HttpContext">HTTP context</see> to get the API feature for.</param>
+        /// <returns>The current <see cref="IApiVersioningFeature">API versioning feature</see>.</returns>
+        public static IApiVersioningFeature ApiVersioningFeature( this HttpContext context )
         {
             if ( context == null )
             {
                 throw new ArgumentNullException( nameof( context ) );
             }
 
             var feature = context.Features.Get<IApiVersioningFeature>();
-            return feature?.RequestedApiVersion;
+
+            if ( feature == null )
+            {
+                feature = new ApiVersioningFeature( context );
+                context.Features.Set( feature );
+            }
+
+            return feature;
         }
+
+        /// <summary>
+        /// Gets the current API version requested.
+        /// </summary>
+        /// <param name="context">The current <see cref="HttpContext">HTTP context</see> to get the API version for.</param>
+        /// <returns>The requested <see cref="ApiVersion">API version</see> or <c>null</c>.</returns>
+        /// <remarks>This method will return <c>null</c> no service API version was requested or the requested
+        /// service API version is in an invalid format.</remarks>
+        /// <exception cref="AmbiguousApiVersionException">Multiple, different API versions were requested.</exception>
+        public static ApiVersion? GetRequestedApiVersion( this HttpContext context ) => context.ApiVersioningFeature().RequestedApiVersion;
     }
 }

src/Microsoft.AspNetCore.Mvc.Versioning/Routing/ApiVersionLinkGenerator.cs

@@ -83,7 +83,7 @@ static void AddApiVersionRouteValueIfNecessary( HttpContext httpContext, RouteVa
                 throw new ArgumentNullException( nameof( values ) );
             }
 
-            var feature = httpContext.Features.Get<IApiVersioningFeature>();
+            var feature = httpContext.ApiVersioningFeature();
             var key = feature.RouteParameter;
 
             if ( string.IsNullOrEmpty( key ) )

src/Microsoft.AspNetCore.Mvc.Versioning/Routing/ApiVersionMatcherPolicy.cs

@@ -93,7 +93,7 @@ public Task ApplyAsync( HttpContext httpContext, CandidateSet candidates )
             if ( apiVersion == null && Options.AssumeDefaultVersionWhenUnspecified )
             {
                 apiVersion = TrySelectApiVersion( httpContext, candidates );
-                httpContext.Features.Get<IApiVersioningFeature>().RequestedApiVersion = apiVersion;
+                httpContext.ApiVersioningFeature().RequestedApiVersion = apiVersion;
             }
 
             var (matched, hasCandidates) = MatchApiVersion( candidates, apiVersion );

src/Microsoft.AspNetCore.Mvc.Versioning/Routing/ApiVersionRouteConstraint.cs

@@ -50,7 +50,7 @@ public bool Match( HttpContext? httpContext, IRouter? route, string routeKey, Ro
                 throw new ArgumentNullException( nameof( httpContext ) );
             }
 
-            var feature = httpContext.Features.Get<IApiVersioningFeature>();
+            var feature = httpContext.ApiVersioningFeature();
 
             feature.RouteParameter = routeKey;
             feature.RawRequestedApiVersion = value;

src/Microsoft.AspNetCore.Mvc.Versioning/Routing/ApiVersionUrlHelper.cs

@@ -21,7 +21,7 @@ public ApiVersionUrlHelper( ActionContext actionContext, IUrlHelper url )
         {
             ActionContext = actionContext ?? throw new ArgumentNullException( nameof( actionContext ) );
             Url = url;
-            feature = actionContext.HttpContext.Features.Get<IApiVersioningFeature>();
+            feature = actionContext.HttpContext.ApiVersioningFeature();
         }
 
         /// <summary>

src/Microsoft.AspNetCore.Mvc.Versioning/Routing/CatchAllRouteHandler.cs

@@ -17,7 +17,7 @@ sealed class CatchAllRouteHandler : IRouter
         /// <inheritdoc />
         public Task RouteAsync( RouteContext context )
         {
-            var feature = context.HttpContext.Features.Get<IApiVersioningFeature>();
+            var feature = context.HttpContext.ApiVersioningFeature();
             routePolicy.Evaluate( context, feature.SelectionResult );
             return CompletedTask;
         }

src/Microsoft.AspNetCore.Mvc.Versioning/Routing/ClientErrorBuilder.cs

@@ -31,7 +31,7 @@ sealed class ClientErrorBuilder
 
         internal RequestHandler Build()
         {
-            var feature = HttpContext!.Features.Get<IApiVersioningFeature>();
+            var feature = HttpContext!.ApiVersioningFeature();
             var request = HttpContext!.Request;
             var method = request.Method;
             var requestedVersion = feature.RawRequestedApiVersion;

src/Microsoft.AspNetCore.Mvc.Versioning/Versioning/ApiVersionActionSelector.cs

@@ -158,7 +158,7 @@ public virtual IReadOnlyList<ActionDescriptor> SelectCandidates( RouteContext co
 
             var selectionContext = new ActionSelectionContext( httpContext, matches, apiVersion );
             var finalMatches = SelectBestActions( selectionContext );
-            var feature = httpContext.Features.Get<IApiVersioningFeature>();
+            var feature = httpContext.ApiVersioningFeature();
             var selectionResult = feature.SelectionResult;
 
             feature.RequestedApiVersion = selectionContext.RequestedVersion;

src/Microsoft.AspNetCore.Mvc.Versioning/Versioning/ApiVersionModelBinder.cs

@@ -20,7 +20,7 @@ public virtual Task BindModelAsync( ModelBindingContext bindingContext )
                 throw new ArgumentNullException( nameof( bindingContext ) );
             }
 
-            var feature = bindingContext.HttpContext.Features.Get<IApiVersioningFeature>();
+            var feature = bindingContext.HttpContext.ApiVersioningFeature();
             var model = feature.RequestedApiVersion;
 
             if ( model != null )

src/Microsoft.AspNetCore.Mvc.Versioning/Versioning/UrlSegmentApiVersionReader.cs

@@ -28,7 +28,7 @@ public partial class UrlSegmentApiVersionReader
             }
 
             reentrant = true;
-            var feature = request.HttpContext.Features.Get<IApiVersioningFeature>();
+            var feature = request.HttpContext.ApiVersioningFeature();
             var value = feature.RawRequestedApiVersion;
             reentrant = false;
 

src/Microsoft.AspNetCore.OData.Versioning/AspNet.OData/Routing/VersionedAttributeRoutingConvention.cs

@@ -145,7 +145,7 @@ protected virtual ApiVersion SelectApiVersion( RouteContext routeContext )
             }
 
             var httpContext = routeContext.HttpContext;
-            var feature = httpContext.Features.Get<IApiVersioningFeature>();
+            var feature = httpContext.ApiVersioningFeature();
             ApiVersion? version;
 
             try

src/Microsoft.AspNetCore.OData.Versioning/AspNet.OData/Routing/VersionedMetadataRoutingConvention.cs

@@ -47,7 +47,7 @@ public class VersionedMetadataRoutingConvention : IODataRoutingConvention
             }
 
             var context = request.HttpContext;
-            var feature = context.Features.Get<IApiVersioningFeature>();
+            var feature = context.ApiVersioningFeature();
             string? apiVersion;
 
             try

src/Microsoft.AspNetCore.OData.Versioning/AspNetCore.Mvc/Versioning/ODataApiVersionActionSelector.cs

@@ -197,7 +197,7 @@ public override IReadOnlyList<ActionDescriptor> SelectCandidates( RouteContext c
                 }
             }
 
-            var feature = httpContext.Features.Get<IApiVersioningFeature>();
+            var feature = httpContext.ApiVersioningFeature();
             var selectionResult = feature.SelectionResult;
 
             feature.RequestedApiVersion = selectionContext.RequestedVersion;