Implements Type in SignalRValueProvider

src/SignalRServiceExtension/Bindings/SignalRInputBindings/SecurityTokenValidationInputBinding.cs

@@ -30,12 +30,8 @@ public Task<IValueProvider> BindAsync(object value, ValueBindingContext context)
                 throw new NotSupportedException($"Argument {nameof(HttpRequest)} is null. {nameof(SecurityTokenValidationAttribute)} must work with HttpTrigger.");
             }
 
-            if (securityTokenValidator == null)
-            {
-                return Task.FromResult((IValueProvider)new SignalRValueProvider(null));
-            }
-
-            return Task.FromResult((IValueProvider)new SignalRValueProvider(securityTokenValidator.ValidateToken(request)));
+            return Task.FromResult(SignalRValueProvider.Create(
+                securityTokenValidator?.ValidateToken(request)));
         }
 
         public Task<IValueProvider> BindAsync(BindingContext context)

src/SignalRServiceExtension/Bindings/SignalRInputBindings/SignalRConnectionInputBinding.cs

@@ -1,12 +1,9 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
 using System.Collections.Generic;
-using System.Reflection;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Azure.WebJobs.Host.Bindings;
-using Microsoft.Azure.WebJobs.Host.Protocols;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Configuration;
 
@@ -37,7 +34,7 @@ protected override Task<IValueProvider> BuildAsync(SignalRConnectionInfoAttribut
             {
                 var info = azureSignalRClient.GetClientConnectionInfo(attrResolved.UserId, attrResolved.IdToken,
                     attrResolved.ClaimTypeList);
-                return Task.FromResult((IValueProvider)new SignalRValueProvider(info));
+                return Task.FromResult(SignalRValueProvider.Create(info));
             }
 
             var request = bindingData[HttpRequestName] as HttpRequest;
@@ -46,14 +43,14 @@ protected override Task<IValueProvider> BuildAsync(SignalRConnectionInfoAttribut
 
             if (tokenResult.Status != SecurityTokenStatus.Valid)
             {
-                return Task.FromResult((IValueProvider)new SignalRValueProvider(null));
+                return Task.FromResult(SignalRValueProvider.NullOf<SignalRConnectionInfo>());
             }
 
             if (signalRConnectionInfoConfigurer == null)
             {
                 var info = azureSignalRClient.GetClientConnectionInfo(attrResolved.UserId, attrResolved.IdToken,
                     attrResolved.ClaimTypeList);
-                return Task.FromResult((IValueProvider)new SignalRValueProvider(info));
+                return Task.FromResult(SignalRValueProvider.Create(info));
             }
 
             var signalRConnectionDetail = new SignalRConnectionDetail
@@ -64,7 +61,7 @@ protected override Task<IValueProvider> BuildAsync(SignalRConnectionInfoAttribut
             signalRConnectionInfoConfigurer.Configure(tokenResult, request, signalRConnectionDetail);
             var customizedInfo = azureSignalRClient.GetClientConnectionInfo(signalRConnectionDetail.UserId,
                 signalRConnectionDetail.Claims);
-            return Task.FromResult((IValueProvider)new SignalRValueProvider(customizedInfo));
+            return Task.FromResult(SignalRValueProvider.Create(customizedInfo));
         }
     }
 }

src/SignalRServiceExtension/Bindings/SignalRInputBindings/SignalRValueProvider.cs

@@ -9,23 +9,47 @@ namespace Microsoft.Azure.WebJobs.Extensions.SignalRService
 {
     internal class SignalRValueProvider : IValueProvider
     {
-        private object value;
+        private readonly Task<object> value;
 
-        public SignalRValueProvider(object value)
+        public Type Type { get; }
+
+        private SignalRValueProvider(object value, Type valueType)
         {
-            this.value = value;
+            this.value = Task.FromResult(value);
+
+            Type = valueType;
         }
 
+        internal static IValueProvider Create<T>(T value) where T : class
+            => value == null
+                ? NullOf<T>()
+                : new SignalRValueProvider(value, value.GetType());
+
+        internal static IValueProvider NullOf<T>() where T : class
+            => SignalRNullValueProvider<T>.Instance;
+
         public Task<object> GetValueAsync()
-        {
-            return Task.FromResult(value);
-        }
+            => value;
 
         public string ToInvokeString()
+            => value.ToString();
+
+        private class SignalRNullValueProvider<T> : IValueProvider
         {
-            return value?.ToString();
-        }
+            private readonly Task<object> nullObjectTask = Task.FromResult<object>(null);
 
-        public Type Type { get; }
+            internal static readonly SignalRNullValueProvider<T> Instance = new SignalRNullValueProvider<T>();
+
+            public Type Type { get; }
+
+            private SignalRNullValueProvider()
+                => Type = typeof(T);
+
+            public Task<object> GetValueAsync()
+                => nullObjectTask;
+
+            public string ToInvokeString()
+                => null;
+        }
     }
-}
+}