Add PageRemoteAttribute (#8324)

* Add PageRemoteAttribute

Fixes https://github.com/aspnet/Mvc/issues/8245

src/Microsoft.AspNetCore.Mvc.ViewFeatures/PageRemoteAttribute.cs

@@ -0,0 +1,59 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
+using Microsoft.AspNetCore.Mvc.Routing;
+using Microsoft.Extensions.DependencyInjection;
+using Resources = Microsoft.AspNetCore.Mvc.ViewFeatures.Resources;
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    /// <summary>
+    /// A <see cref="RemoteAttributeBase"/> for razor page handler which configures Unobtrusive validation 
+    /// to send an Ajax request to the web site. The invoked handler should return JSON indicating 
+    /// whether the value is valid.
+    /// </summary>
+    /// <remarks>Does no server-side validation of the final form submission.</remarks>
+    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
+    public class PageRemoteAttribute : RemoteAttributeBase
+    {
+        /// <summary>
+        /// The handler name used when generating the URL where client should send a validation request.
+        /// </summary>
+        /// <remarks>
+        /// If not set the ambient value will be used when generating the URL.
+        /// </remarks>
+        public string PageHandler { get; set; }
+
+        /// <summary>
+        /// The page name used when generating the URL where client should send a validation request.
+        /// </summary>
+        /// <remarks>
+        /// If not set the ambient value will be used when generating the URL.
+        /// </remarks>
+        public string PageName { get; set; }
+
+        /// <inheritdoc />
+        protected override string GetUrl(ClientModelValidationContext context)
+        {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+            
+            var services = context.ActionContext.HttpContext.RequestServices;
+            var factory = services.GetRequiredService<IUrlHelperFactory>();
+            var urlHelper = factory.GetUrlHelper(context.ActionContext);
+
+            var url = urlHelper.Page(PageName, PageHandler, RouteData);
+            
+            if (url == null)
+            {
+                throw new InvalidOperationException(Resources.RemoteAttribute_NoUrlFound);
+            }
+
+            return url;
+        }
+    }
+}

src/Microsoft.AspNetCore.Mvc.ViewFeatures/RemoteAttribute.cs

@@ -2,34 +2,21 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations;
-using System.Globalization;
-using System.Linq;
-using Microsoft.AspNetCore.Mvc.DataAnnotations;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
 using Microsoft.AspNetCore.Mvc.Routing;
-using Microsoft.AspNetCore.Routing;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Localization;
-using Microsoft.Extensions.Options;
 using Resources = Microsoft.AspNetCore.Mvc.ViewFeatures.Resources;
 
 namespace Microsoft.AspNetCore.Mvc
 {
     /// <summary>
-    /// A <see cref="ValidationAttribute"/> which configures Unobtrusive validation to send an Ajax request to the
+    /// A <see cref="RemoteAttributeBase"/> for controllers which configures Unobtrusive validation to send an Ajax request to the
     /// web site. The invoked action should return JSON indicating whether the value is valid.
     /// </summary>
     /// <remarks>Does no server-side validation of the final form submission.</remarks>
     [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
-    public class RemoteAttribute : ValidationAttribute, IClientModelValidator
+    public class RemoteAttribute : RemoteAttributeBase
     {
-        private string _additionalFields = string.Empty;
-        private string[] _additionalFieldsSplit = Array.Empty<string>();
-        private bool _checkedForLocalizer;
-        private IStringLocalizer _stringLocalizer;
-
         /// <summary>
         /// Initializes a new instance of the <see cref="RemoteAttribute"/> class.
         /// </summary>
@@ -37,10 +24,7 @@ namespace Microsoft.AspNetCore.Mvc
         /// Intended for subclasses that support URL generation with no route, action, or controller names.
         /// </remarks>
         protected RemoteAttribute()
-            : base(errorMessageAccessor: () => Resources.RemoteAttribute_RemoteValidationFailed)
+        { }
-        {
-            RouteData = new RouteValueDictionary();
-        }
 
         /// <summary>
         /// Initializes a new instance of the <see cref="RemoteAttribute"/> class.
@@ -112,90 +96,14 @@ namespace Microsoft.AspNetCore.Mvc
         {
             RouteData["area"] = areaName;
         }
-
+        
-        /// <summary>
-        /// Gets or sets the HTTP method (<c>"Get"</c> or <c>"Post"</c>) client should use when sending a validation
-        /// request.
-        /// </summary>
-        public string HttpMethod { get; set; }
-
-        /// <summary>
-        /// Gets or sets the comma-separated names of fields the client should include in a validation request.
-        /// </summary>
-        public string AdditionalFields
-        {
-            get => _additionalFields;
-            set
-            {
-                _additionalFields = value ?? string.Empty;
-                _additionalFieldsSplit = SplitAndTrimPropertyNames(value)
-                    .Select(field => FormatPropertyForClientValidation(field))
-                    .ToArray();
-            }
-        }
-
-        /// <summary>
-        /// Gets the <see cref="RouteValueDictionary"/> used when generating the URL where client should send a
-        /// validation request.
-        /// </summary>
-        protected RouteValueDictionary RouteData { get; }
-
         /// <summary>
         /// Gets or sets the route name used when generating the URL where client should send a validation request.
         /// </summary>
         protected string RouteName { get; set; }
 
-        /// <summary>
+        /// <inheritdoc />
-        /// Formats <paramref name="property"/> and <see cref="AdditionalFields"/> for use in generated HTML.
+        protected override string GetUrl(ClientModelValidationContext context)
-        /// </summary>
-        /// <param name="property">
-        /// Name of the property associated with this <see cref="RemoteAttribute"/> instance.
-        /// </param>
-        /// <returns>Comma-separated names of fields the client should include in a validation request.</returns>
-        /// <remarks>
-        /// Excludes any whitespace from <see cref="AdditionalFields"/> in the return value.
-        /// Prefixes each field name in the return value with <c>"*."</c>.
-        /// </remarks>
-        public string FormatAdditionalFieldsForClientValidation(string property)
-        {
-            if (string.IsNullOrEmpty(property))
-            {
-                throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(property));
-            }
-
-            var delimitedAdditionalFields = string.Join(",", _additionalFieldsSplit);
-            if (!string.IsNullOrEmpty(delimitedAdditionalFields))
-            {
-                delimitedAdditionalFields = "," + delimitedAdditionalFields;
-            }
-
-            var formattedString = FormatPropertyForClientValidation(property) + delimitedAdditionalFields;
-
-            return formattedString;
-        }
-
-        /// <summary>
-        /// Formats <paramref name="property"/> for use in generated HTML.
-        /// </summary>
-        /// <param name="property">One field name the client should include in a validation request.</param>
-        /// <returns>Name of a field the client should include in a validation request.</returns>
-        /// <remarks>Returns <paramref name="property"/> with a <c>"*."</c> prefix.</remarks>
-        public static string FormatPropertyForClientValidation(string property)
-        {
-            if (string.IsNullOrEmpty(property))
-            {
-                throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(property));
-            }
-
-            return "*." + property;
-        }
-
-        /// <summary>
-        /// Returns the URL where the client should send a validation request.
-        /// </summary>
-        /// <param name="context">The <see cref="ClientModelValidationContext"/> used to generate the URL.</param>
-        /// <returns>The URL where the client should send a validation request.</returns>
-        protected virtual string GetUrl(ClientModelValidationContext context)
         {
             if (context == null)
             {
@@ -219,101 +127,5 @@ namespace Microsoft.AspNetCore.Mvc
 
             return url;
         }
-
-        /// <inheritdoc />
-        public override string FormatErrorMessage(string name)
-        {
-            return string.Format(CultureInfo.CurrentCulture, ErrorMessageString, name);
-        }
-
-        /// <inheritdoc />
-        /// <remarks>
-        /// Always returns <c>true</c> since this <see cref="ValidationAttribute"/> does no validation itself.
-        /// Related validations occur only when the client sends a validation request.
-        /// </remarks>
-        public override bool IsValid(object value)
-        {
-            return true;
-        }
-
-        public virtual void AddValidation(ClientModelValidationContext context)
-        {
-            if (context == null)
-            {
-                throw new ArgumentNullException(nameof(context));
-            }
-
-            MergeAttribute(context.Attributes, "data-val", "true");
-
-            CheckForLocalizer(context);
-            var errorMessage = GetErrorMessage(context.ModelMetadata.GetDisplayName());
-            MergeAttribute(context.Attributes, "data-val-remote", errorMessage);
-
-            MergeAttribute(context.Attributes, "data-val-remote-url", GetUrl(context));
-
-            if (!string.IsNullOrEmpty(HttpMethod))
-            {
-                MergeAttribute(context.Attributes, "data-val-remote-type", HttpMethod);
-            }
-
-            var additionalFields = FormatAdditionalFieldsForClientValidation(context.ModelMetadata.PropertyName);
-            MergeAttribute(context.Attributes, "data-val-remote-additionalfields", additionalFields);
-        }
-
-        private static void MergeAttribute(IDictionary<string, string> attributes, string key, string value)
-        {
-            if (!attributes.ContainsKey(key))
-            {
-                attributes.Add(key, value);
-            }
-        }
-
-        private static IEnumerable<string> SplitAndTrimPropertyNames(string original)
-        {
-            if (string.IsNullOrEmpty(original))
-            {
-                return Array.Empty<string>();
-            }
-
-            var split = original
-                .Split(',')
-                .Select(piece => piece.Trim())
-                .Where(trimmed => !string.IsNullOrEmpty(trimmed));
-
-            return split;
-        }
-
-        private void CheckForLocalizer(ClientModelValidationContext context)
-        {
-            if (!_checkedForLocalizer)
-            {
-                _checkedForLocalizer = true;
-
-                var services = context.ActionContext.HttpContext.RequestServices;
-                var options = services.GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
-                var factory = services.GetService<IStringLocalizerFactory>();
-
-                var provider = options.Value.DataAnnotationLocalizerProvider;
-                if (factory != null && provider != null)
-                {
-                    _stringLocalizer = provider(
-                        context.ModelMetadata.ContainerType ?? context.ModelMetadata.ModelType,
-                        factory);
-                }
-            }
-        }
-
-        private string GetErrorMessage(string displayName)
-        {
-            if (_stringLocalizer != null &&
-                !string.IsNullOrEmpty(ErrorMessage) &&
-                string.IsNullOrEmpty(ErrorMessageResourceName) &&
-                ErrorMessageResourceType == null)
-            {
-                return _stringLocalizer[ErrorMessage, displayName];
-            }
-
-            return FormatErrorMessage(displayName);
-        }
     }
 }

src/Microsoft.AspNetCore.Mvc.ViewFeatures/RemoteAttributeBase.cs

@@ -0,0 +1,224 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.Globalization;
+using System.Linq;
+using Microsoft.AspNetCore.Mvc.DataAnnotations;
+using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Localization;
+using Microsoft.Extensions.Options;
+using Resources = Microsoft.AspNetCore.Mvc.ViewFeatures.Resources;
+
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    /// <summary>
+    /// A <see cref="ValidationAttribute"/> which configures Unobtrusive validation to send an Ajax request to the
+    /// web site. The invoked endpoint should return JSON indicating whether the value is valid.
+    /// </summary>
+    /// <remarks>Does no server-side validation of the final form submission.</remarks>
+    [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
+    public abstract class RemoteAttributeBase : ValidationAttribute, IClientModelValidator
+    {
+        private string _additionalFields = string.Empty;
+        private string[] _additionalFieldsSplit = Array.Empty<string>();
+        private bool _checkedForLocalizer;
+        private IStringLocalizer _stringLocalizer;
+        
+        protected RemoteAttributeBase()
+            : base(errorMessageAccessor: () => Resources.RemoteAttribute_RemoteValidationFailed)
+        {
+            RouteData = new RouteValueDictionary();
+        }
+
+        /// <summary>
+        /// Gets the <see cref="RouteValueDictionary"/> used when generating the URL where client should send a
+        /// validation request.
+        /// </summary>
+        protected RouteValueDictionary RouteData { get; }
+
+        /// <summary>
+        /// Gets or sets the HTTP method (<c>"Get"</c> or <c>"Post"</c>) client should use when sending a validation
+        /// request.
+        /// </summary>
+        public string HttpMethod { get; set; }
+
+        /// <summary>
+        /// Gets or sets the comma-separated names of fields the client should include in a validation request.
+        /// </summary>
+        public string AdditionalFields
+        {
+            get => _additionalFields;
+            set
+            {
+                _additionalFields = value ?? string.Empty;
+                _additionalFieldsSplit = SplitAndTrimPropertyNames(value)
+                    .Select(field => FormatPropertyForClientValidation(field))
+                    .ToArray();
+            }
+        }
+        
+        /// <summary>
+        /// Formats <paramref name="property"/> and <see cref="AdditionalFields"/> for use in generated HTML.
+        /// </summary>
+        /// <param name="property">
+        /// Name of the property associated with this <see cref="RemoteAttribute"/> instance.
+        /// </param>
+        /// <returns>Comma-separated names of fields the client should include in a validation request.</returns>
+        /// <remarks>
+        /// Excludes any whitespace from <see cref="AdditionalFields"/> in the return value.
+        /// Prefixes each field name in the return value with <c>"*."</c>.
+        /// </remarks>
+        public string FormatAdditionalFieldsForClientValidation(string property)
+        {
+            if (string.IsNullOrEmpty(property))
+            {
+                throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(property));
+            }
+
+            var delimitedAdditionalFields = string.Join(",", _additionalFieldsSplit);
+            if (!string.IsNullOrEmpty(delimitedAdditionalFields))
+            {
+                delimitedAdditionalFields = "," + delimitedAdditionalFields;
+            }
+
+            var formattedString = FormatPropertyForClientValidation(property) + delimitedAdditionalFields;
+
+            return formattedString;
+        }
+
+        /// <summary>
+        /// Formats <paramref name="property"/> for use in generated HTML.
+        /// </summary>
+        /// <param name="property">One field name the client should include in a validation request.</param>
+        /// <returns>Name of a field the client should include in a validation request.</returns>
+        /// <remarks>Returns <paramref name="property"/> with a <c>"*."</c> prefix.</remarks>
+        public static string FormatPropertyForClientValidation(string property)
+        {
+            if (string.IsNullOrEmpty(property))
+            {
+                throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(property));
+            }
+
+            return "*." + property;
+        }
+
+        /// <summary>
+        /// Returns the URL where the client should send a validation request.
+        /// </summary>
+        /// <param name="context">The <see cref="ClientModelValidationContext"/> used to generate the URL.</param>
+        /// <returns>The URL where the client should send a validation request.</returns>
+        protected abstract string GetUrl(ClientModelValidationContext context);
+        
+        /// <inheritdoc />
+        public override string FormatErrorMessage(string name)
+        {
+            return string.Format(CultureInfo.CurrentCulture, ErrorMessageString, name);
+        }
+
+        /// <inheritdoc />
+        /// <remarks>
+        /// Always returns <c>true</c> since this <see cref="ValidationAttribute"/> does no validation itself.
+        /// Related validations occur only when the client sends a validation request.
+        /// </remarks>
+        public override bool IsValid(object value)
+        {
+            return true;
+        }
+
+        /// <summary>
+        /// Adds Unobtrusive validation HTML attributes to <see cref="ClientModelValidationContext"/>.
+        /// </summary>
+        /// <param name="context">
+        /// <see cref="ClientModelValidationContext"/> to add Unobtrusive validation HTML attributes to.
+        /// </param>
+        /// <remarks>
+        /// Calls derived <see cref="ValidationAttribute"/> implementation of <see cref="GetUrl(ClientModelValidationContext)"/>.
+        /// </remarks>
+        public virtual void AddValidation(ClientModelValidationContext context)
+        {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            MergeAttribute(context.Attributes, "data-val", "true");
+
+            CheckForLocalizer(context);
+            var errorMessage = GetErrorMessage(context.ModelMetadata.GetDisplayName());
+            MergeAttribute(context.Attributes, "data-val-remote", errorMessage);
+
+            MergeAttribute(context.Attributes, "data-val-remote-url", GetUrl(context));
+
+            if (!string.IsNullOrEmpty(HttpMethod))
+            {
+                MergeAttribute(context.Attributes, "data-val-remote-type", HttpMethod);
+            }
+
+            var additionalFields = FormatAdditionalFieldsForClientValidation(context.ModelMetadata.PropertyName);
+            MergeAttribute(context.Attributes, "data-val-remote-additionalfields", additionalFields);
+        }
+
+        private static void MergeAttribute(IDictionary<string, string> attributes, string key, string value)
+        {
+            if (!attributes.ContainsKey(key))
+            {
+                attributes.Add(key, value);
+            }
+        }
+
+        private static IEnumerable<string> SplitAndTrimPropertyNames(string original)
+        {
+            if (string.IsNullOrEmpty(original))
+            {
+                return Array.Empty<string>();
+            }
+
+            var split = original
+                .Split(',')
+                .Select(piece => piece.Trim())
+                .Where(trimmed => !string.IsNullOrEmpty(trimmed));
+
+            return split;
+        }
+
+        private void CheckForLocalizer(ClientModelValidationContext context)
+        {
+            if (!_checkedForLocalizer)
+            {
+                _checkedForLocalizer = true;
+
+                var services = context.ActionContext.HttpContext.RequestServices;
+                var options = services.GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
+                var factory = services.GetService<IStringLocalizerFactory>();
+
+                var provider = options.Value.DataAnnotationLocalizerProvider;
+                if (factory != null && provider != null)
+                {
+                    _stringLocalizer = provider(
+                        context.ModelMetadata.ContainerType ?? context.ModelMetadata.ModelType,
+                        factory);
+                }
+            }
+        }
+
+        private string GetErrorMessage(string displayName)
+        {
+            if (_stringLocalizer != null &&
+                !string.IsNullOrEmpty(ErrorMessage) &&
+                string.IsNullOrEmpty(ErrorMessageResourceName) &&
+                ErrorMessageResourceType == null)
+            {
+                return _stringLocalizer[ErrorMessage, displayName];
+            }
+
+            return FormatErrorMessage(displayName);
+        }
+    }
+}
+

src/Microsoft.AspNetCore.Mvc.ViewFeatures/breakingchanges.netcore.json

@@ -42,5 +42,9 @@
     "TypeId": "public class Microsoft.AspNetCore.Mvc.ViewFeatures.HtmlHelper<T0> : Microsoft.AspNetCore.Mvc.ViewFeatures.HtmlHelper, Microsoft.AspNetCore.Mvc.Rendering.IHtmlHelper<T0>",
     "MemberId": "public .ctor(Microsoft.AspNetCore.Mvc.ViewFeatures.IHtmlGenerator htmlGenerator, Microsoft.AspNetCore.Mvc.ViewEngines.ICompositeViewEngine viewEngine, Microsoft.AspNetCore.Mvc.ModelBinding.IModelMetadataProvider metadataProvider, Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.IViewBufferScope bufferScope, System.Text.Encodings.Web.HtmlEncoder htmlEncoder, System.Text.Encodings.Web.UrlEncoder urlEncoder, Microsoft.AspNetCore.Mvc.ViewFeatures.Internal.ExpressionTextCache expressionTextCache)",
     "Kind": "Removal"
+  },
+  {
+	"TypeId": "public class Microsoft.AspNetCore.Mvc.RemoteAttribute : System.ComponentModel.DataAnnotations.ValidationAttribute, Microsoft.AspNetCore.Mvc.ModelBinding.Validation.IClientModelValidator",
+	"Kind": "Removal"
   }
 ]

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/PageRemoteAttributeTest.cs

@@ -0,0 +1,271 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
+using Microsoft.AspNetCore.Mvc.Routing;
+using Microsoft.AspNetCore.Mvc.ViewFeatures;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.AspNetCore.Testing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.ObjectPool;
+using Microsoft.Extensions.Options;
+using Moq;
+using Xunit;
+using Resources = Microsoft.AspNetCore.Mvc.ViewFeatures.Resources;
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    public class PageRemoteAttributeTest
+    {
+        [Fact]
+        public void GetUrl_CallsUrlHelperWithExpectedValues()
+        {
+            // Arrange
+            var testableAttribute = new TestablePageRemoteAttribute
+            {
+                PageName = "Foo",
+                PageHandler = "Bar"
+            };
+
+            var ambientValues = new RouteValueDictionary()
+            {
+                ["page"] = "/Foo"
+            };
+
+            var routeData = new RouteData(ambientValues)
+            {
+                Routers = { Mock.Of<IRouter>() }
+            };
+
+            var urlHelper = new MockUrlHelper(url: "/Foo?handler=Bar")
+            {
+                ActionContext = GetActionContext(new ServiceCollection().BuildServiceProvider(), routeData)
+            };
+
+            var validationContext = GetValidationContext(urlHelper);
+
+            // Act
+            testableAttribute.InvokeGetUrl(validationContext);
+
+            // Assert
+            var routeDictionary = Assert.IsType<RouteValueDictionary>(urlHelper.RouteValues);
+
+            Assert.Equal(2, routeDictionary.Count);
+            Assert.Equal("/Foo", routeDictionary["page"] as string);
+            Assert.Equal("Bar", routeDictionary["handler"] as string);
+        }
+
+        [Fact]
+        public void GetUrl_WhenUrlHelperReturnsNull_Throws()
+        {
+            // Arrange
+            var testableAttribute = new TestablePageRemoteAttribute
+            {
+                PageName = "Foo",
+                PageHandler = "Bar"
+            };
+
+            var ambientValues = new RouteValueDictionary
+            {
+                ["page"] = "/Page"
+            };
+
+            var routeData = new RouteData(ambientValues)
+            {
+                Routers = { Mock.Of<IRouter>() }
+            };
+            
+            var urlHelper = new MockUrlHelper(url: null)
+            {
+                ActionContext = GetActionContext(new ServiceCollection().BuildServiceProvider(), routeData)
+            };
+
+            var validationContext = GetValidationContext(urlHelper);
+
+            // Act && Assert
+            ExceptionAssert.Throws<InvalidOperationException>(
+                () => testableAttribute.InvokeGetUrl(validationContext),
+                Resources.RemoteAttribute_NoUrlFound);
+        }
+
+        [Fact]
+        public void GetUrl_WhenPageNameIsNotSet_WillUsePageNameFromAmbientValues()
+        {
+            // Arrange
+            var testableAttribute = new TestablePageRemoteAttribute()
+            {
+                PageHandler = "Handler"
+            };
+
+            var ambientValues = new RouteValueDictionary
+            {
+                ["page"] = "/Page"
+            };
+
+            var routeData = new RouteData(ambientValues)
+            {
+                Routers = { Mock.Of<IRouter>() }
+            };
+
+            var urlHelper = new MockUrlHelper(url: "/Page?handler=Handler")
+            {
+                ActionContext = GetActionContext(new ServiceCollection().BuildServiceProvider(), routeData)
+            };
+
+            var validationContext = GetValidationContext(urlHelper);
+
+            // Act
+            var actualUrl = testableAttribute.InvokeGetUrl(validationContext);
+
+            // Assert
+            Assert.Equal("/Page?handler=Handler", actualUrl);
+        }
+
+        [Fact]
+        public void GetUrl_WhenPageNameAndPageHandlerIsNotSet_WillUseAmbientValues()
+        {
+            // Arrange
+            var testableAttribute = new TestablePageRemoteAttribute();
+
+            var ambientValues = new RouteValueDictionary
+            {
+                ["page"] = "/Page",
+                ["handler"] = "Handler"
+            };
+
+            var routeData = new RouteData(ambientValues)
+            {
+                Routers = { Mock.Of<IRouter>() }
+            };
+
+            var urlHelper = new MockUrlHelper(url: "/Page?handler=Handler")
+            {
+                ActionContext = GetActionContext(new ServiceCollection().BuildServiceProvider(), routeData)
+            };
+
+            var validationContext = GetValidationContext(urlHelper);
+
+            // Act
+            var actualUrl = testableAttribute.InvokeGetUrl(validationContext);
+
+            // Assert
+            Assert.Equal("/Page?handler=Handler", actualUrl);
+        }
+        
+        private static ClientModelValidationContext GetValidationContext(IUrlHelper urlHelper, RouteData routeData = null)
+        {
+            var serviceCollection = GetServiceCollection();
+            var factory = new Mock<IUrlHelperFactory>(MockBehavior.Strict);
+            serviceCollection.AddSingleton<IUrlHelperFactory>(factory.Object);
+
+            var serviceProvider = serviceCollection.BuildServiceProvider();
+            var actionContext = GetActionContext(serviceProvider, routeData);
+
+            factory
+                .Setup(f => f.GetUrlHelper(actionContext))
+                .Returns(urlHelper);
+
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var metadata = metadataProvider.GetMetadataForProperty(
+                containerType: typeof(string),
+                propertyName: nameof(string.Length));
+
+            return new ClientModelValidationContext(
+                actionContext,
+                metadata,
+                metadataProvider,
+                new AttributeDictionary());
+        }
+
+        private static ServiceCollection GetServiceCollection()
+        {
+            var serviceCollection = new ServiceCollection();
+            serviceCollection
+                .AddSingleton<ObjectPoolProvider, DefaultObjectPoolProvider>()
+                .AddSingleton<ILoggerFactory>(new NullLoggerFactory());
+
+            serviceCollection.AddOptions();
+            serviceCollection.AddRouting();
+
+            serviceCollection.AddSingleton<IInlineConstraintResolver>(
+                provider => new DefaultInlineConstraintResolver(provider.GetRequiredService<IOptions<RouteOptions>>(), provider));
+
+            return serviceCollection;
+        }
+
+        private static ActionContext GetActionContext(IServiceProvider serviceProvider, RouteData routeData)
+        {
+            // Set IServiceProvider properties because TemplateRoute gets services (e.g. an ILoggerFactory instance)
+            // through the HttpContext.
+            var httpContext = new DefaultHttpContext
+            {
+                RequestServices = serviceProvider,
+            };
+
+            if (routeData == null)
+            {
+                routeData = new RouteData
+                {
+                    Routers = { Mock.Of<IRouter>(), },
+                };
+            }
+
+            return new ActionContext(httpContext, routeData, new ActionDescriptor());
+        }
+
+        private class TestablePageRemoteAttribute : PageRemoteAttribute
+        {
+            public string InvokeGetUrl(ClientModelValidationContext context)
+            {
+                return base.GetUrl(context);
+            }
+        }
+
+        private class MockUrlHelper : IUrlHelper
+        {
+            private readonly string _url;
+
+            public MockUrlHelper(string url)
+            {
+                _url = url;
+            }
+
+            public ActionContext ActionContext { get; set; }
+
+            public object RouteValues { get; private set; }
+
+            public string Action(UrlActionContext actionContext)
+            {
+                throw new NotImplementedException();
+            }
+
+            public string Content(string contentPath)
+            {
+                throw new NotImplementedException();
+            }
+
+            public bool IsLocalUrl(string url)
+            {
+                throw new NotImplementedException();
+            }
+
+            public string Link(string routeName, object values)
+            {
+                throw new NotImplementedException();
+            }
+
+            public string RouteUrl(UrlRouteContext routeContext)
+            {
+                RouteValues = routeContext.Values;
+
+                return _url;
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/RemoteAttributeBaseTest.cs

@@ -0,0 +1,539 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Abstractions;
+using Microsoft.AspNetCore.Mvc.DataAnnotations;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
+using Microsoft.AspNetCore.Mvc.ViewFeatures;
+using Microsoft.AspNetCore.Routing;
+using Microsoft.AspNetCore.Testing;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Localization;
+using Microsoft.Extensions.Options;
+using Moq;
+using Xunit;
+using Resources = Microsoft.AspNetCore.Mvc.ViewFeatures.Test.Resources;
+
+namespace Microsoft.AspNetCore.Mvc
+{
+    public class RemoteAttributeBaseTest
+    {
+        // Null or empty property names are invalid. (Those containing just whitespace are legal.)
+        public static TheoryData<string> NullOrEmptyNames
+        {
+            get
+            {
+                return new TheoryData<string>
+                {
+                    null,
+                    string.Empty,
+                };
+            }
+        }
+        
+        [Fact]
+        public void IsValidAlwaysReturnsTrue()
+        {
+            // Arrange
+            var attribute = new TestableRemoteAttributeBase();
+
+            // Act & Assert
+            Assert.True(attribute.IsValid(value: null));
+        }
+        
+        [Fact]
+        public void ErrorMessageProperties_HaveExpectedDefaultValues()
+        {
+            // Arrange & Act
+            var attribute = new TestableRemoteAttributeBase();
+
+            // Assert
+            Assert.Null(attribute.ErrorMessage);
+            Assert.Null(attribute.ErrorMessageResourceName);
+            Assert.Null(attribute.ErrorMessageResourceType);
+        }
+        
+        [Fact]
+        [ReplaceCulture]
+        public void FormatErrorMessage_ReturnsDefaultErrorMessage()
+        {
+            // Arrange
+            // See ViewFeatures.Resources.RemoteAttribute_RemoteValidationFailed.
+            var expected = "'Property1' is invalid.";
+            var attribute = new TestableRemoteAttributeBase();
+
+            // Act
+            var message = attribute.FormatErrorMessage("Property1");
+            
+            // Assert
+            Assert.Equal(expected, message);
+        }
+        
+        [Fact]
+        public void FormatErrorMessage_UsesOverriddenErrorMessage()
+        {
+            // Arrange
+            var expected = "Error about 'Property1' from override.";
+            var attribute = new TestableRemoteAttributeBase()
+            {
+                ErrorMessage = "Error about '{0}' from override.",
+            };
+
+            // Act
+            var message = attribute.FormatErrorMessage("Property1");
+
+            // Assert
+            Assert.Equal(expected, message);
+        }
+        
+        [Fact]
+        [ReplaceCulture]
+        public void FormatErrorMessage_UsesErrorMessageFromResource()
+        {
+            // Arrange
+            var expected = "Error about 'Property1' from resources.";
+            var attribute = new TestableRemoteAttributeBase()
+            {
+                ErrorMessageResourceName = nameof(Resources.RemoteAttribute_Error),
+                ErrorMessageResourceType = typeof(Resources)
+            };
+
+            // Act
+            var message = attribute.FormatErrorMessage("Property1");
+
+            // Assert
+            Assert.Equal(expected, message);
+        }
+        
+        [Theory]
+        [MemberData(nameof(NullOrEmptyNames))]
+        public void FormatAdditionalFieldsForClientValidation_WithInvalidPropertyName_Throws(string property)
+        {
+            // Arrange
+            var attribute = new TestableRemoteAttributeBase();
+            var expectedMessage = "Value cannot be null or empty.";
+
+            // Act & Assert
+            ExceptionAssert.ThrowsArgument(
+                () => attribute.FormatAdditionalFieldsForClientValidation(property),
+                "property",
+                expectedMessage);
+        }
+
+        [Fact]
+        public void FormatAdditionalFieldsForClientValidation_WillFormat_AdditionalFields()
+        {
+            // Arrange
+            var attribute = new TestableRemoteAttributeBase
+            {
+                AdditionalFields = "FieldOne, FieldTwo"
+            };
+
+            // Act
+            var actual = attribute.FormatAdditionalFieldsForClientValidation("Property");
+
+            // Assert
+            var expected = "*.Property,*.FieldOne,*.FieldTwo";
+            Assert.Equal(expected, actual);
+        }
+
+        [Theory]
+        [MemberData(nameof(NullOrEmptyNames))]
+        public void FormatPropertyForClientValidation_WithInvalidPropertyName_Throws(string property)
+        {
+            // Arrange
+            var expected = "Value cannot be null or empty.";
+
+            // Act & Assert
+            ExceptionAssert.ThrowsArgument(
+                () => RemoteAttributeBase.FormatPropertyForClientValidation(property),
+                "property",
+                expected);
+        }
+        
+        [Fact]
+        public void AddValidation_WithErrorMessage_SetsAttributesAsExpected()
+        {
+            // Arrange
+            var expected = "Error about 'Length' from override.";
+            var url = "/Controller/Action";
+            var context = GetValidationContext();
+            var attribute = new TestableRemoteAttributeBase(dummyGetUrlReturnValue: url)
+            {
+                HttpMethod = "POST",
+                ErrorMessage = "Error about '{0}' from override.",
+            };
+            
+            // Act
+            attribute.AddValidation(context);
+
+            // Assert
+            Assert.Collection(
+                context.Attributes,
+                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote", kvp.Key);
+                    Assert.Equal(expected, kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
+                    Assert.Equal("*.Length", kvp.Value);
+                },
+                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
+                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
+        }
+        
+        [Fact]
+        public void AddValidation_WithErrorMessageAndLocalizerFactory_SetsAttributesAsExpected()
+        {
+            // Arrange
+            var expected = "Error about 'Length' from override.";
+            var url = "/Controller/Action";
+            var localizerFactory = new Mock<IStringLocalizerFactory>(MockBehavior.Strict).Object;
+            var context = GetValidationContext(localizerFactory);
+            var attribute = new TestableRemoteAttributeBase(dummyGetUrlReturnValue: url)
+            {
+                HttpMethod = "POST",
+                ErrorMessage = "Error about '{0}' from override.",
+            };
+            
+            // Act
+            attribute.AddValidation(context);
+
+            // Assert
+            Assert.Collection(
+                context.Attributes,
+                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
+                kvp =>
+                {
+                    // IStringLocalizerFactory existence alone is insufficient to change error message.
+                    Assert.Equal("data-val-remote", kvp.Key);
+                    Assert.Equal(expected, kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
+                    Assert.Equal("*.Length", kvp.Value);
+                },
+                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
+                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
+        }
+        
+        [Fact]
+        public void AddValidation_WithErrorMessageAndLocalizerProvider_SetsAttributesAsExpected()
+        {
+            // Arrange
+            var expected = "Error about 'Length' from override.";
+            var url = "/Controller/Action";
+            var context = GetValidationContext();
+            var attribute = new TestableRemoteAttributeBase(url)
+            {
+                HttpMethod = "POST",
+                ErrorMessage = "Error about '{0}' from override.",
+            };
+
+            var options = context.ActionContext.HttpContext.RequestServices
+                .GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
+            var localizer = new Mock<IStringLocalizer>(MockBehavior.Strict);
+            options.Value.DataAnnotationLocalizerProvider = (type, factory) => localizer.Object;
+
+            // Act
+            attribute.AddValidation(context);
+
+            // Assert
+            Assert.Collection(
+                context.Attributes,
+                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
+                kvp =>
+                {
+                    // Non-null DataAnnotationLocalizerProvider alone is insufficient to change error message.
+                    Assert.Equal("data-val-remote", kvp.Key);
+                    Assert.Equal(expected, kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
+                    Assert.Equal("*.Length", kvp.Value);
+                },
+                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
+                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
+        }
+        
+        [Fact]
+        public void AddValidation_WithErrorMessageLocalizerFactoryAndLocalizerProvider_SetsAttributesAsExpected()
+        {
+            // Arrange
+            var expected = "Error about 'Length' from localizer.";
+            var url = "/Controller/Action";
+            var localizerFactory = new Mock<IStringLocalizerFactory>(MockBehavior.Strict).Object;
+            var context = GetValidationContext(localizerFactory);
+            var attribute = new TestableRemoteAttributeBase(dummyGetUrlReturnValue: url)
+            {
+                HttpMethod = "POST",
+                ErrorMessage = "Error about '{0}' from override.",
+            };
+
+            var localizedString = new LocalizedString("Fred", expected);
+            var localizer = new Mock<IStringLocalizer>(MockBehavior.Strict);
+            localizer
+                .Setup(l => l["Error about '{0}' from override.", "Length"])
+                .Returns(localizedString)
+                .Verifiable();
+            var options = context.ActionContext.HttpContext.RequestServices
+                .GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
+            options.Value.DataAnnotationLocalizerProvider = (type, factory) => localizer.Object;
+
+            // Act
+            attribute.AddValidation(context);
+
+            // Assert
+            localizer.VerifyAll();
+
+            Assert.Collection(
+                context.Attributes,
+                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote", kvp.Key);
+                    Assert.Equal(expected, kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
+                    Assert.Equal("*.Length", kvp.Value);
+                },
+                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
+                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
+        }
+        
+        [Fact]
+        [ReplaceCulture]
+        public void AddValidation_WithErrorResourcesLocalizerFactoryAndLocalizerProvider_SetsAttributesAsExpected()
+        {
+            // Arrange
+            var expected = "Error about 'Length' from resources.";
+            var url = "/Controller/Action";
+            var attribute = new TestableRemoteAttributeBase(dummyGetUrlReturnValue: url)
+            {
+                HttpMethod = "POST",
+                ErrorMessageResourceName = nameof(Resources.RemoteAttribute_Error),
+                ErrorMessageResourceType = typeof(Resources),
+            };
+            
+            var localizerFactory = new Mock<IStringLocalizerFactory>(MockBehavior.Strict).Object;
+            var context = GetValidationContext(localizerFactory);
+
+            var localizer = new Mock<IStringLocalizer>(MockBehavior.Strict);
+            var options = context.ActionContext.HttpContext.RequestServices
+                .GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
+            options.Value.DataAnnotationLocalizerProvider = (type, factory) => localizer.Object;
+
+            // Act
+            attribute.AddValidation(context);
+
+            // Assert
+            Assert.Collection(
+                context.Attributes,
+                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
+                kvp =>
+                {
+                    // Configuring the attribute using ErrorMessageResource* trumps available IStringLocalizer etc.
+                    Assert.Equal("data-val-remote", kvp.Key);
+                    Assert.Equal(expected, kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
+                    Assert.Equal("*.Length", kvp.Value);
+                },
+                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
+                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
+        }
+        
+        [Fact]
+        public void AddValidation_WithErrorMessageAndDisplayName_SetsAttributesAsExpected()
+        {
+            // Arrange
+            var expected = "Error about 'Display Length' from override.";
+            var url = "/Controller/Action";
+
+            var metadataProvider = new TestModelMetadataProvider();
+            metadataProvider
+                .ForProperty(typeof(string), nameof(string.Length))
+                .DisplayDetails(d => d.DisplayName = () => "Display Length");
+            var context = GetValidationContext(localizerFactory: null, metadataProvider: metadataProvider);
+
+            var attribute = new TestableRemoteAttributeBase(dummyGetUrlReturnValue: url)
+            {
+                HttpMethod = "POST",
+                ErrorMessage = "Error about '{0}' from override.",
+            };
+            
+            // Act
+            attribute.AddValidation(context);
+
+            // Assert
+            Assert.Collection(
+                context.Attributes,
+                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote", kvp.Key);
+                    Assert.Equal(expected, kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
+                    Assert.Equal("*.Length", kvp.Value);
+                },
+                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
+                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
+        }
+        
+        [Fact]
+        public void AddValidation_WithErrorMessageLocalizerFactoryLocalizerProviderAndDisplayName_SetsAttributesAsExpected()
+        {
+            // Arrange
+            var expected = "Error about 'Length' from localizer.";
+            var url = "/Controller/Action";
+
+            var metadataProvider = new TestModelMetadataProvider();
+            metadataProvider
+                .ForProperty(typeof(string), nameof(string.Length))
+                .DisplayDetails(d => d.DisplayName = () => "Display Length");
+            var localizerFactory = new Mock<IStringLocalizerFactory>(MockBehavior.Strict).Object;
+            var context = GetValidationContext(localizerFactory, metadataProvider);
+
+            var attribute = new TestableRemoteAttributeBase(dummyGetUrlReturnValue: url)
+            {
+                HttpMethod = "POST",
+                ErrorMessage = "Error about '{0}' from override.",
+            };
+
+            var localizedString = new LocalizedString("Fred", expected);
+            var localizer = new Mock<IStringLocalizer>(MockBehavior.Strict);
+            localizer
+                .Setup(l => l["Error about '{0}' from override.", "Display Length"])
+                .Returns(localizedString)
+                .Verifiable();
+            var options = context.ActionContext.HttpContext.RequestServices
+                .GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
+            options.Value.DataAnnotationLocalizerProvider = (type, factory) => localizer.Object;
+
+            // Act
+            attribute.AddValidation(context);
+
+            // Assert
+            localizer.VerifyAll();
+
+            Assert.Collection(
+                context.Attributes,
+                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote", kvp.Key);
+                    Assert.Equal(expected, kvp.Value);
+                },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
+                    Assert.Equal("*.Length", kvp.Value);
+                },
+                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
+                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
+        }
+        
+        [Fact]
+        public void AddValidation_WillSetAttributes_ToExpectedValues()
+        {
+            // Arrange
+            var url = "/Controller/Action";
+            var attribute = new TestableRemoteAttributeBase(dummyGetUrlReturnValue: url)
+            {
+                HttpMethod = "POST",
+                AdditionalFields = "Password,ConfirmPassword",
+                ErrorMessage = "Error"
+            };
+            var context = GetValidationContext();
+
+            // Act
+            attribute.AddValidation(context);
+
+            // Assert
+            Assert.Collection(
+                context.Attributes,
+                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
+                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("Error", kvp.Value); },
+                kvp =>
+                {
+                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
+                    Assert.Equal("*.Length,*.Password,*.ConfirmPassword", kvp.Value);
+                },
+                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
+                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
+        }
+
+        private static ClientModelValidationContext GetValidationContext(
+            IStringLocalizerFactory localizerFactory = null,
+            IModelMetadataProvider metadataProvider = null)
+        {
+            var serviceCollection = new ServiceCollection();
+            serviceCollection.AddOptions();
+            if (localizerFactory != null)
+            {
+                serviceCollection.AddSingleton<IStringLocalizerFactory>(localizerFactory);
+            }
+
+            var serviceProvider = serviceCollection.BuildServiceProvider();
+            
+            var httpContext = new DefaultHttpContext
+            {
+                RequestServices = serviceProvider,
+            };
+            
+            var actionContext = new ActionContext(
+                httpContext, 
+                routeData: new Mock<RouteData>().Object, 
+                actionDescriptor: new ActionDescriptor());
+            
+            var emptyMetadataProvider = new EmptyModelMetadataProvider();
+
+            if (metadataProvider == null)
+            {
+                metadataProvider = new EmptyModelMetadataProvider();
+            }
+
+            var metadata = metadataProvider.GetMetadataForProperty(
+                containerType: typeof(string),
+                propertyName: nameof(string.Length));
+
+            return new ClientModelValidationContext(
+                actionContext,
+                metadata,
+                metadataProvider,
+                new AttributeDictionary());
+        }
+
+        private class TestableRemoteAttributeBase : RemoteAttributeBase
+        {
+            private readonly string _dummyGetUrlReturnValue;
+
+            public TestableRemoteAttributeBase()
+            { }
+            
+            public TestableRemoteAttributeBase(string dummyGetUrlReturnValue)
+            {
+                _dummyGetUrlReturnValue = dummyGetUrlReturnValue;
+            }
+
+            protected override string GetUrl(ClientModelValidationContext context)
+            {
+                return _dummyGetUrlReturnValue;
+            }
+        }
+    }
+}

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/RemoteAttributeTest.cs

@@ -5,7 +5,6 @@ using System;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc.Abstractions;
-using Microsoft.AspNetCore.Mvc.DataAnnotations;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Validation;
 using Microsoft.AspNetCore.Mvc.Routing;
@@ -13,24 +12,17 @@ using Microsoft.AspNetCore.Mvc.ViewFeatures;
 using Microsoft.AspNetCore.Routing;
 using Microsoft.AspNetCore.Testing;
 using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Extensions.Localization;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
 using Microsoft.Extensions.ObjectPool;
 using Microsoft.Extensions.Options;
 using Moq;
 using Xunit;
-using Resources = Microsoft.AspNetCore.Mvc.ViewFeatures.Test.Resources;
 
 namespace Microsoft.AspNetCore.Mvc
 {
     public class RemoteAttributeTest
     {
-        private static readonly IModelMetadataProvider _metadataProvider = new EmptyModelMetadataProvider();
-        private static readonly ModelMetadata _metadata = _metadataProvider.GetMetadataForProperty(
-            typeof(string),
-            nameof(string.Length));
-
         public static TheoryData<string> SomeNames
         {
             get
@@ -57,15 +49,7 @@ namespace Microsoft.AspNetCore.Mvc
                 };
             }
         }
-
+        
-        [Fact]
-        public void IsValidAlwaysReturnsTrue()
-        {
-            // Act & Assert
-            Assert.True(new RemoteAttribute("RouteName", "ParameterName").IsValid(value: null));
-            Assert.True(new RemoteAttribute("ActionName", "ControllerName", "ParameterName").IsValid(value: null));
-        }
-
         [Fact]
         public void Constructor_WithNullAction_IgnoresArgument()
         {
@@ -157,516 +141,74 @@ namespace Microsoft.AspNetCore.Mvc
             Assert.Equal(areaName, resultName);
             Assert.Null(attribute.RouteName);
         }
-
+        
         [Fact]
-        public void ErrorMessageProperties_HaveExpectedDefaultValues()
+        public void GetUrl_WithBadRouteName_Throws()
-        {
-            // Arrange & Act
-            var attribute = new RemoteAttribute("Action", "Controller");
-
-            // Assert
-            Assert.Null(attribute.ErrorMessage);
-            Assert.Null(attribute.ErrorMessageResourceName);
-            Assert.Null(attribute.ErrorMessageResourceType);
-        }
-
-        [Fact]
-        [ReplaceCulture]
-        public void FormatErrorMessage_ReturnsDefaultErrorMessage()
         {
             // Arrange
-            // See ViewFeatures.Resources.RemoteAttribute_RemoteValidationFailed.
+            var testableAttribute = new TestableRemoteAttribute("nonexistentRoute");
-            var expected = "'Property1' is invalid.";
-            var attribute = new RemoteAttribute("Action", "Controller");
-
-            // Act
-            var message = attribute.FormatErrorMessage("Property1");
-
-            // Assert
-            Assert.Equal(expected, message);
-        }
-
-        [Fact]
-        public void FormatErrorMessage_UsesOverriddenErrorMessage()
-        {
-            // Arrange
-            var expected = "Error about 'Property1' from override.";
-            var attribute = new RemoteAttribute("Action", "Controller")
-            {
-                ErrorMessage = "Error about '{0}' from override.",
-            };
-
-            // Act
-            var message = attribute.FormatErrorMessage("Property1");
-
-            // Assert
-            Assert.Equal(expected, message);
-        }
-
-        [Fact]
-        [ReplaceCulture]
-        public void FormatErrorMessage_UsesErrorMessageFromResource()
-        {
-            // Arrange
-            var expected = "Error about 'Property1' from resources.";
-            var attribute = new RemoteAttribute("Action", "Controller")
-            {
-                ErrorMessageResourceName = nameof(Resources.RemoteAttribute_Error),
-                ErrorMessageResourceType = typeof(Resources),
-            };
-
-            // Act
-            var message = attribute.FormatErrorMessage("Property1");
-
-            // Assert
-            Assert.Equal(expected, message);
-        }
-
-        [Theory]
-        [MemberData(nameof(NullOrEmptyNames))]
-        public void FormatAdditionalFieldsForClientValidation_WithInvalidPropertyName_Throws(string property)
-        {
-            // Arrange
-            var attribute = new RemoteAttribute(routeName: "default");
-            var expectedMessage = "Value cannot be null or empty.";
-
-            // Act & Assert
-            ExceptionAssert.ThrowsArgument(
-                () => attribute.FormatAdditionalFieldsForClientValidation(property),
-                "property",
-                expectedMessage);
-        }
-
-        [Theory]
-        [MemberData(nameof(NullOrEmptyNames))]
-        public void FormatPropertyForClientValidation_WithInvalidPropertyName_Throws(string property)
-        {
-            // Arrange
-            var expected = "Value cannot be null or empty.";
-
-            // Act & Assert
-            ExceptionAssert.ThrowsArgument(
-                () => RemoteAttribute.FormatPropertyForClientValidation(property),
-                "property",
-                expected);
-        }
-
-        [Fact]
-        public void AddValidation_WithBadRouteName_Throws()
-        {
-            // Arrange
-            var attribute = new RemoteAttribute("nonexistentRoute");
             var context = GetValidationContextWithArea(currentArea: null);
 
             // Act & Assert
-            var exception = Assert.Throws<InvalidOperationException>(() => attribute.AddValidation(context));
+            var exception = Assert.Throws<InvalidOperationException>(() => testableAttribute.InvokeGetUrl(context));
             Assert.Equal("No URL for remote validation could be found.", exception.Message);
         }
 
         [Fact]
-        [ReplaceCulture]
+        public void GetUrl_WithRoute_CallsUrlHelperWithExpectedValues()
-        public void AddValidation_WithRoute_CallsUrlHelperWithExpectedValues()
         {
             // Arrange
             var routeName = "RouteName";
-            var attribute = new RemoteAttribute(routeName);
+            var testableRemoteAttribute = new TestableRemoteAttribute(routeName);
             var url = "/my/URL";
             var urlHelper = new MockUrlHelper(url, routeName);
             var context = GetValidationContext(urlHelper);
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableRemoteAttribute.InvokeGetUrl(context);
-
+            
             // Assert
-            Assert.Collection(
+            Assert.Equal(url, actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-additionalfields", kvp.Key); Assert.Equal("*.Length", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
 
             var routeDictionary = Assert.IsType<RouteValueDictionary>(urlHelper.RouteValues);
             Assert.Empty(routeDictionary);
         }
 
         [Fact]
-        [ReplaceCulture]
+        public void GetUrl_WithActionController_CallsUrlHelperWithExpectedValues()
-        public void AddValidation_WithActionController_CallsUrlHelperWithExpectedValues()
         {
             // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller");
+            var testableRemoteAttribute = new TestableRemoteAttribute("Action", "Controller");
             var url = "/Controller/Action";
             var urlHelper = new MockUrlHelper(url, routeName: null);
             var context = GetValidationContext(urlHelper);
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableRemoteAttribute.InvokeGetUrl(context);
 
             // Assert
-            Assert.Collection(
+            Assert.Equal(url, actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-additionalfields", kvp.Key); Assert.Equal("*.Length", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
 
             var routeDictionary = Assert.IsType<RouteValueDictionary>(urlHelper.RouteValues);
             Assert.Equal(2, routeDictionary.Count);
             Assert.Equal("Action", routeDictionary["action"] as string);
             Assert.Equal("Controller", routeDictionary["controller"] as string);
         }
-
+        
         [Fact]
-        [ReplaceCulture]
+        public void GetUrl_WithActionControllerArea_CallsUrlHelperWithExpectedValues()
-        public void AddValidation_WithActionController_PropertiesSet_CallsUrlHelperWithExpectedValues()
         {
             // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller")
+            var testableAttribute = new TestableRemoteAttribute("Action", "Controller", "Test");
-            {
-                HttpMethod = "POST",
-                AdditionalFields = "Password,ConfirmPassword",
-            };
-            var url = "/Controller/Action";
-            var urlHelper = new MockUrlHelper(url, routeName: null);
-            var context = GetValidationContext(urlHelper);
-
-            // Act
-            attribute.AddValidation(context);
-
-            // Assert
-            Assert.Collection(
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
-                    Assert.Equal("*.Length,*.Password,*.ConfirmPassword", kvp.Value);
-                },
-                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
-
-            var routeDictionary = Assert.IsType<RouteValueDictionary>(urlHelper.RouteValues);
-            Assert.Equal(2, routeDictionary.Count);
-            Assert.Equal("Action", routeDictionary["action"] as string);
-            Assert.Equal("Controller", routeDictionary["controller"] as string);
-        }
-
-        [Fact]
-        public void AddValidation_WithErrorMessage_SetsAttributesAsExpected()
-        {
-            // Arrange
-            var expected = "Error about 'Length' from override.";
-            var attribute = new RemoteAttribute("Action", "Controller")
-            {
-                HttpMethod = "POST",
-                ErrorMessage = "Error about '{0}' from override.",
-            };
-            var url = "/Controller/Action";
-            var context = GetValidationContext(url);
-
-            // Act
-            attribute.AddValidation(context);
-
-            // Assert
-            Assert.Collection(
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote", kvp.Key);
-                    Assert.Equal(expected, kvp.Value);
-                },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
-                    Assert.Equal("*.Length", kvp.Value);
-                },
-                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
-        }
-
-        [Fact]
-        public void AddValidation_WithErrorMessageAndLocalizerFactory_SetsAttributesAsExpected()
-        {
-            // Arrange
-            var expected = "Error about 'Length' from override.";
-            var attribute = new RemoteAttribute("Action", "Controller")
-            {
-                HttpMethod = "POST",
-                ErrorMessage = "Error about '{0}' from override.",
-            };
-            var url = "/Controller/Action";
-            var context = GetValidationContextWithLocalizerFactory(url);
-
-            // Act
-            attribute.AddValidation(context);
-
-            // Assert
-            Assert.Collection(
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp =>
-                {
-                    // IStringLocalizerFactory existence alone is insufficient to change error message.
-                    Assert.Equal("data-val-remote", kvp.Key);
-                    Assert.Equal(expected, kvp.Value);
-                },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
-                    Assert.Equal("*.Length", kvp.Value);
-                },
-                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
-        }
-
-        [Fact]
-        public void AddValidation_WithErrorMessageAndLocalizerProvider_SetsAttributesAsExpected()
-        {
-            // Arrange
-            var expected = "Error about 'Length' from override.";
-            var attribute = new RemoteAttribute("Action", "Controller")
-            {
-                HttpMethod = "POST",
-                ErrorMessage = "Error about '{0}' from override.",
-            };
-            var url = "/Controller/Action";
-            var context = GetValidationContext(url);
-
-            var options = context.ActionContext.HttpContext.RequestServices
-                .GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
-            var localizer = new Mock<IStringLocalizer>(MockBehavior.Strict);
-            options.Value.DataAnnotationLocalizerProvider = (type, factory) => localizer.Object;
-
-            // Act
-            attribute.AddValidation(context);
-
-            // Assert
-            Assert.Collection(
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp =>
-                {
-                    // Non-null DataAnnotationLocalizerProvider alone is insufficient to change error message.
-                    Assert.Equal("data-val-remote", kvp.Key);
-                    Assert.Equal(expected, kvp.Value);
-                },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
-                    Assert.Equal("*.Length", kvp.Value);
-                },
-                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
-        }
-
-        [Fact]
-        public void AddValidation_WithErrorMessageLocalizerFactoryAndLocalizerProvider_SetsAttributesAsExpected()
-        {
-            // Arrange
-            var expected = "Error about 'Length' from localizer.";
-            var attribute = new RemoteAttribute("Action", "Controller")
-            {
-                HttpMethod = "POST",
-                ErrorMessage = "Error about '{0}' from override.",
-            };
-            var url = "/Controller/Action";
-            var context = GetValidationContextWithLocalizerFactory(url);
-
-            var localizedString = new LocalizedString("Fred", expected);
-            var localizer = new Mock<IStringLocalizer>(MockBehavior.Strict);
-            localizer
-                .Setup(l => l["Error about '{0}' from override.", "Length"])
-                .Returns(localizedString)
-                .Verifiable();
-            var options = context.ActionContext.HttpContext.RequestServices
-                .GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
-            options.Value.DataAnnotationLocalizerProvider = (type, factory) => localizer.Object;
-
-            // Act
-            attribute.AddValidation(context);
-
-            // Assert
-            localizer.VerifyAll();
-
-            Assert.Collection(
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote", kvp.Key);
-                    Assert.Equal(expected, kvp.Value);
-                },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
-                    Assert.Equal("*.Length", kvp.Value);
-                },
-                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
-        }
-
-        [Fact]
-        [ReplaceCulture]
-        public void AddValidation_WithErrorResourcesLocalizerFactoryAndLocalizerProvider_SetsAttributesAsExpected()
-        {
-            // Arrange
-            var expected = "Error about 'Length' from resources.";
-            var attribute = new RemoteAttribute("Action", "Controller")
-            {
-                HttpMethod = "POST",
-                ErrorMessageResourceName = nameof(Resources.RemoteAttribute_Error),
-                ErrorMessageResourceType = typeof(Resources),
-            };
-            var url = "/Controller/Action";
-            var context = GetValidationContextWithLocalizerFactory(url);
-
-            var localizer = new Mock<IStringLocalizer>(MockBehavior.Strict);
-            var options = context.ActionContext.HttpContext.RequestServices
-                .GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
-            options.Value.DataAnnotationLocalizerProvider = (type, factory) => localizer.Object;
-
-            // Act
-            attribute.AddValidation(context);
-
-            // Assert
-            Assert.Collection(
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp =>
-                {
-                    // Configuring the attribute using ErrorMessageResource* trumps available IStringLocalizer etc.
-                    Assert.Equal("data-val-remote", kvp.Key);
-                    Assert.Equal(expected, kvp.Value);
-                },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
-                    Assert.Equal("*.Length", kvp.Value);
-                },
-                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
-        }
-
-        [Fact]
-        public void AddValidation_WithErrorMessageAndDisplayName_SetsAttributesAsExpected()
-        {
-            // Arrange
-            var expected = "Error about 'Display Length' from override.";
-            var attribute = new RemoteAttribute("Action", "Controller")
-            {
-                HttpMethod = "POST",
-                ErrorMessage = "Error about '{0}' from override.",
-            };
-
-            var url = "/Controller/Action";
-            var metadataProvider = new TestModelMetadataProvider();
-            metadataProvider
-                .ForProperty(typeof(string), nameof(string.Length))
-                .DisplayDetails(d => d.DisplayName = () => "Display Length");
-            var context = GetValidationContext(url, metadataProvider);
-
-            // Act
-            attribute.AddValidation(context);
-
-            // Assert
-            Assert.Collection(
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote", kvp.Key);
-                    Assert.Equal(expected, kvp.Value);
-                },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
-                    Assert.Equal("*.Length", kvp.Value);
-                },
-                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
-        }
-
-        [Fact]
-        public void AddValidation_WithErrorMessageLocalizerFactoryLocalizerProviderAndDisplayName_SetsAttributesAsExpected()
-        {
-            // Arrange
-            var expected = "Error about 'Length' from localizer.";
-            var attribute = new RemoteAttribute("Action", "Controller")
-            {
-                HttpMethod = "POST",
-                ErrorMessage = "Error about '{0}' from override.",
-            };
-
-            var url = "/Controller/Action";
-            var metadataProvider = new TestModelMetadataProvider();
-            metadataProvider
-                .ForProperty(typeof(string), nameof(string.Length))
-                .DisplayDetails(d => d.DisplayName = () => "Display Length");
-            var context = GetValidationContextWithLocalizerFactory(url, metadataProvider);
-
-            var localizedString = new LocalizedString("Fred", expected);
-            var localizer = new Mock<IStringLocalizer>(MockBehavior.Strict);
-            localizer
-                .Setup(l => l["Error about '{0}' from override.", "Display Length"])
-                .Returns(localizedString)
-                .Verifiable();
-            var options = context.ActionContext.HttpContext.RequestServices
-                .GetRequiredService<IOptions<MvcDataAnnotationsLocalizationOptions>>();
-            options.Value.DataAnnotationLocalizerProvider = (type, factory) => localizer.Object;
-
-            // Act
-            attribute.AddValidation(context);
-
-            // Assert
-            localizer.VerifyAll();
-
-            Assert.Collection(
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote", kvp.Key);
-                    Assert.Equal(expected, kvp.Value);
-                },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
-                    Assert.Equal("*.Length", kvp.Value);
-                },
-                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
-        }
-
-        [Fact]
-        [ReplaceCulture]
-        public void AddValidation_WithActionControllerArea_CallsUrlHelperWithExpectedValues()
-        {
-            // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller", "Test")
-            {
-                HttpMethod = "POST",
-            };
             var url = "/Test/Controller/Action";
             var urlHelper = new MockUrlHelper(url, routeName: null);
             var context = GetValidationContext(urlHelper);
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableAttribute.InvokeGetUrl(context);
 
             // Assert
-            Assert.Collection(
+            Assert.Equal(url, actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-additionalfields", kvp.Key);
-                    Assert.Equal("*.Length", kvp.Value);
-                },
-                kvp => { Assert.Equal("data-val-remote-type", kvp.Key); Assert.Equal("POST", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal(url, kvp.Value); });
 
             var routeDictionary = Assert.IsType<RouteValueDictionary>(urlHelper.RouteValues);
             Assert.Equal(3, routeDictionary.Count);
@@ -677,179 +219,109 @@ namespace Microsoft.AspNetCore.Mvc
 
         // Root area is current in this case.
         [Fact]
-        [ReplaceCulture]
+        public void GetUrl_WithActionController_FindsControllerInCurrentArea()
-        public void AddValidation_WithActionController_FindsControllerInCurrentArea()
         {
             // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller");
+            var testableAttribute = new TestableRemoteAttribute("Action", "Controller");
             var context = GetValidationContextWithArea(currentArea: null);
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableAttribute.InvokeGetUrl(context);
 
             // Assert
-            Assert.Collection(
+            Assert.Equal("/Controller/Action", actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-additionalfields", kvp.Key); Assert.Equal("*.Length", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-url", kvp.Key);
-                    Assert.Equal("/Controller/Action", kvp.Value);
-                });
         }
 
         // Test area is current in this case.
         [Fact]
-        [ReplaceCulture]
+        public void GetUrl_WithActionControllerInArea_FindsControllerInCurrentArea()
-        public void AddValidation_WithActionControllerInArea_FindsControllerInCurrentArea()
         {
             // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller");
+            var testableAttribute = new TestableRemoteAttribute("Action", "Controller");
             var context = GetValidationContextWithArea(currentArea: "Test");
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableAttribute.InvokeGetUrl(context);
 
             // Assert
-            Assert.Collection(
+            Assert.Equal("/Test/Controller/Action", actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-additionalfields", kvp.Key); Assert.Equal("*.Length", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-url", kvp.Key);
-                    Assert.Equal("/Test/Controller/Action", kvp.Value);
-                });
         }
 
         // Explicit reference to the (current) root area.
         [Theory]
         [MemberData(nameof(NullOrEmptyNames))]
-        [ReplaceCulture]
+        public void GetUrl_WithActionControllerArea_FindsControllerInRootArea(string areaName)
-        public void AddValidation_WithActionControllerArea_FindsControllerInRootArea(string areaName)
         {
             // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller", areaName);
+            var testableAttribute = new TestableRemoteAttribute("Action", "Controller", areaName);
             var context = GetValidationContextWithArea(currentArea: null);
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableAttribute.InvokeGetUrl(context);
 
             // Assert
-            Assert.Collection(
+            Assert.Equal("/Controller/Action", actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-additionalfields", kvp.Key); Assert.Equal("*.Length", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-url", kvp.Key);
-                    Assert.Equal("/Controller/Action", kvp.Value);
-                });
         }
 
         // Test area is current in this case.
         [Theory]
         [MemberData(nameof(NullOrEmptyNames))]
-        [ReplaceCulture]
+        public void GetUrl_WithActionControllerAreaInArea_FindsControllerInRootArea(string areaName)
-        public void AddValidation_WithActionControllerAreaInArea_FindsControllerInRootArea(string areaName)
         {
             // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller", areaName);
+            var testableAttribute = new TestableRemoteAttribute("Action", "Controller", areaName);
             var context = GetValidationContextWithArea(currentArea: "Test");
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableAttribute.InvokeGetUrl(context);
 
             // Assert
-            Assert.Collection(
+            Assert.Equal("/Controller/Action", actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-additionalfields", kvp.Key); Assert.Equal("*.Length", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-url", kvp.Key);
-                    Assert.Equal("/Controller/Action", kvp.Value);
-                });
         }
 
         // Root area is current in this case.
         [Fact]
-        [ReplaceCulture]
+        public void GetUrl_WithActionControllerArea_FindsControllerInNamedArea()
-        public void AddValidation_WithActionControllerArea_FindsControllerInNamedArea()
         {
             // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller", "Test");
+            var testableAttribute = new TestableRemoteAttribute("Action", "Controller", "Test");
             var context = GetValidationContextWithArea(currentArea: null);
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableAttribute.InvokeGetUrl(context);
 
             // Assert
-            Assert.Collection(
+            Assert.Equal("/Test/Controller/Action", actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-additionalfields", kvp.Key); Assert.Equal("*.Length", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-url", kvp.Key);
-                    Assert.Equal("/Test/Controller/Action", kvp.Value);
-                });
         }
 
         // Explicit reference to the current (Test) area.
         [Fact]
-        [ReplaceCulture]
+        public void GetUrl_WithActionControllerAreaInArea_FindsControllerInNamedArea()
-        public void AddValidation_WithActionControllerAreaInArea_FindsControllerInNamedArea()
         {
             // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller", "Test");
+            var testableAttribute = new TestableRemoteAttribute("Action", "Controller", "Test");
             var context = GetValidationContextWithArea(currentArea: "Test");
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableAttribute.InvokeGetUrl(context);
 
             // Assert
-            Assert.Collection(
+            Assert.Equal("/Test/Controller/Action", actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-additionalfields", kvp.Key); Assert.Equal("*.Length", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-url", kvp.Key);
-                    Assert.Equal("/Test/Controller/Action", kvp.Value);
-                });
         }
 
         // Test area is current in this case.
         [Fact]
-        [ReplaceCulture]
+        public void GetUrl_WithActionControllerAreaInArea_FindsControllerInDifferentArea()
-        public void AddValidation_WithActionControllerAreaInArea_FindsControllerInDifferentArea()
         {
             // Arrange
-            var attribute = new RemoteAttribute("Action", "Controller", "AnotherArea");
+            var testableAttribute = new TestableRemoteAttribute("Action", "Controller", "AnotherArea");
             var context = GetValidationContextWithArea(currentArea: "Test");
 
             // Act
-            attribute.AddValidation(context);
+            var actualUrl = testableAttribute.InvokeGetUrl(context);
 
             // Assert
-            Assert.Collection(
+            Assert.Equal("/AnotherArea/Controller/Action", actualUrl);
-                context.Attributes,
-                kvp => { Assert.Equal("data-val", kvp.Key); Assert.Equal("true", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote", kvp.Key); Assert.Equal("'Length' is invalid.", kvp.Value); },
-                kvp => { Assert.Equal("data-val-remote-additionalfields", kvp.Key); Assert.Equal("*.Length", kvp.Value); },
-                kvp =>
-                {
-                    Assert.Equal("data-val-remote-url", kvp.Key);
-                    Assert.Equal("/AnotherArea/Controller/Action", kvp.Value);
-                });
         }
 
         // Test area is current in this case.
@@ -883,29 +355,16 @@ namespace Microsoft.AspNetCore.Mvc
                 kvp => { Assert.Equal("data-val-remote-url", kvp.Key); Assert.Equal("original", kvp.Value); });
         }
 
-        private static ClientModelValidationContext GetValidationContext(
+        private static ClientModelValidationContext GetValidationContext(string url)
-            string url,
-            IModelMetadataProvider metadataProvider = null)
         {
             var urlHelper = new MockUrlHelper(url, routeName: null);
-            return GetValidationContext(urlHelper, localizerFactory: null, metadataProvider: metadataProvider);
+            return GetValidationContext(urlHelper);
         }
-
+        
-        private static ClientModelValidationContext GetValidationContextWithLocalizerFactory(
-            string url,
-            IModelMetadataProvider metadataProvider = null)
-        {
-            var urlHelper = new MockUrlHelper(url, routeName: null);
-            var localizerFactory = new Mock<IStringLocalizerFactory>(MockBehavior.Strict);
-            return GetValidationContext(urlHelper, localizerFactory.Object, metadataProvider);
-        }
-
         private static ClientModelValidationContext GetValidationContext(
-            IUrlHelper urlHelper,
+            IUrlHelper urlHelper)
-            IStringLocalizerFactory localizerFactory = null,
-            IModelMetadataProvider metadataProvider = null)
         {
-            var serviceCollection = GetServiceCollection(localizerFactory);
+            var serviceCollection = GetServiceCollection();
             var factory = new Mock<IUrlHelperFactory>(MockBehavior.Strict);
             serviceCollection.AddSingleton<IUrlHelperFactory>(factory.Object);
 
@@ -915,17 +374,12 @@ namespace Microsoft.AspNetCore.Mvc
             factory
                 .Setup(f => f.GetUrlHelper(actionContext))
                 .Returns(urlHelper);
-
+            
-            var metadata = _metadata;
+            var metadataProvider = new EmptyModelMetadataProvider();
-            if (metadataProvider == null)
+            var metadata = metadataProvider.GetMetadataForProperty(
-            {
+                containerType: typeof(string),
-                metadataProvider = _metadataProvider;
+                propertyName: nameof(string.Length));
-            }
+            
-            else
-            {
-                metadata = metadataProvider.GetMetadataForProperty(typeof(string), nameof(string.Length));
-            }
-
             return new ClientModelValidationContext(
                 actionContext,
                 metadata,
@@ -935,7 +389,7 @@ namespace Microsoft.AspNetCore.Mvc
 
         private static ClientModelValidationContext GetValidationContextWithArea(string currentArea)
         {
-            var serviceCollection = GetServiceCollection(localizerFactory: null);
+            var serviceCollection = GetServiceCollection();
             var serviceProvider = serviceCollection.BuildServiceProvider();
             var routeCollection = GetRouteCollectionWithArea(serviceProvider);
             var routeData = new RouteData
@@ -968,10 +422,15 @@ namespace Microsoft.AspNetCore.Mvc
             serviceProvider = serviceCollection.BuildServiceProvider();
             actionContext.HttpContext.RequestServices = serviceProvider;
 
+            var metadataProvider = new EmptyModelMetadataProvider();
+            var metadata = metadataProvider.GetMetadataForProperty(
+                containerType: typeof(string),
+                propertyName: nameof(string.Length));
+
             return new ClientModelValidationContext(
                  actionContext,
-                 _metadata,
+                 metadata,
-                 _metadataProvider,
+                 metadataProvider,
                  new AttributeDictionary());
         }
 
@@ -987,15 +446,7 @@ namespace Microsoft.AspNetCore.Mvc
 
             return builder.Build();
         }
-
+        
-        private static IRouter GetRouteCollectionWithNoController(IServiceProvider serviceProvider)
-        {
-            var builder = GetRouteBuilder(serviceProvider);
-            builder.MapRoute("default", "static/route");
-
-            return builder.Build();
-        }
-
         private static RouteBuilder GetRouteBuilder(IServiceProvider serviceProvider)
         {
             var app = new Mock<IApplicationBuilder>(MockBehavior.Strict);
@@ -1034,7 +485,7 @@ namespace Microsoft.AspNetCore.Mvc
             return new ActionContext(httpContext, routeData, new ActionDescriptor());
         }
 
-        private static ServiceCollection GetServiceCollection(IStringLocalizerFactory localizerFactory)
+        private static ServiceCollection GetServiceCollection()
         {
             var serviceCollection = new ServiceCollection();
             serviceCollection
@@ -1047,11 +498,6 @@ namespace Microsoft.AspNetCore.Mvc
             serviceCollection.AddSingleton<IInlineConstraintResolver>(
                 provider => new DefaultInlineConstraintResolver(provider.GetRequiredService<IOptions<RouteOptions>>(), provider));
 
-            if (localizerFactory != null)
-            {
-                serviceCollection.AddSingleton<IStringLocalizerFactory>(localizerFactory);
-            }
-
             return serviceCollection;
         }
 
@@ -1135,6 +581,11 @@ namespace Microsoft.AspNetCore.Mvc
                     return base.RouteData;
                 }
             }
+
+            public string InvokeGetUrl(ClientModelValidationContext context)
+            {
+                return base.GetUrl(context);
+            }
         }
     }
 }