Make /Pages the default root for pages.

Fixes #6184

samples/MvcSandbox/Startup.cs

@@ -16,7 +16,7 @@ public class Startup
         // This method gets called by the runtime. Use this method to add services to the container.
         public void ConfigureServices(IServiceCollection services)
         {
-            services.AddMvc().AddCookieTempDataProvider();
+            services.AddMvc();
 
             services.Insert(0, ServiceDescriptor.Singleton(
                 typeof(IConfigureOptions<AntiforgeryOptions>),

src/Microsoft.AspNetCore.Mvc.RazorPages/DependencyInjection/MvcRazorPagesMvcBuilderExtensions.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Mvc.Razor;
 using Microsoft.AspNetCore.Mvc.RazorPages;
 
@@ -35,5 +36,48 @@ public static IMvcBuilder AddRazorPagesOptions(
             builder.Services.Configure(setupAction);
             return builder;
         }
+
+        /// <summary>
+        /// Configures Razor Pages to use the specified <paramref name="rootDirectory"/>.
+        /// </summary>
+        /// <param name="builder">The <see cref="IMvcCoreBuilder"/>.</param>
+        /// <param name="rootDirectory">The application relative path to use as the root directory.</param>
+        /// <returns>The <see cref="IMvcBuilder"/>.</returns>
+        public static IMvcBuilder WithRazorPagesRoot(this IMvcBuilder builder, string rootDirectory)
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            if (string.IsNullOrEmpty(rootDirectory))
+            {
+                throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(rootDirectory));
+            }
+
+            if (rootDirectory[0] != '/')
+            {
+                throw new ArgumentException(Resources.PathMustBeAnAppRelativePath, nameof(rootDirectory));
+            }
+
+            builder.Services.Configure<RazorPagesOptions>(options => options.RootDirectory = rootDirectory);
+            return builder;
+        }
+
+        /// <summary>
+        /// Configures Razor Pages to be rooted at the content root (<see cref="IHostingEnvironment.ContentRootPath"/>).
+        /// </summary>
+        /// <param name="builder">The <see cref="IMvcCoreBuilder"/>.</param>
+        /// <returns>The <see cref="IMvcBuilder"/>.</returns>
+        public static IMvcBuilder WithRazorPagesAtContentRoot(this IMvcBuilder builder)
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            builder.Services.Configure<RazorPagesOptions>(options => options.RootDirectory = "/");
+            return builder;
+        }
     }
 }

src/Microsoft.AspNetCore.Mvc.RazorPages/DependencyInjection/MvcRazorPagesMvcCoreBuilderExtensions.cs

@@ -58,6 +58,28 @@ public static IMvcCoreBuilder AddRazorPages(
             return builder;
         }
 
+        /// <summary>
+        /// Configures Razor Pages to use the specified <paramref name="rootDirectory"/>.
+        /// </summary>
+        /// <param name="builder">The <see cref="IMvcCoreBuilder"/>.</param>
+        /// <param name="rootDirectory">The application relative path to use as the root directory.</param>
+        /// <returns></returns>
+        public static IMvcCoreBuilder WithRazorPagesRoot(this IMvcCoreBuilder builder, string rootDirectory)
+        {
+            if (builder == null)
+            {
+                throw new ArgumentNullException(nameof(builder));
+            }
+
+            if (string.IsNullOrEmpty(rootDirectory))
+            {
+                throw new ArgumentException(Resources.ArgumentCannotBeNullOrEmpty, nameof(rootDirectory));
+            }
+
+            builder.Services.Configure<RazorPagesOptions>(options => options.RootDirectory = rootDirectory);
+            return builder;
+        }
+
         private static void AddFeatureProviders(IMvcCoreBuilder builder)
         {
             if (!builder.PartManager.FeatureProviders.OfType<CompiledPageFeatureProvider>().Any())

src/Microsoft.AspNetCore.Mvc.RazorPages/Internal/RazorPagesOptionsSetup.cs

@@ -22,6 +22,8 @@ public void Configure(RazorPagesOptions options)
 
             // Always require an antiforgery token on post
             options.ConfigureFilter(new AutoValidateAntiforgeryTokenAttribute());
+
+            options.RootDirectory = "/Pages";
         }
     }
 }

test/Microsoft.AspNetCore.Mvc.FunctionalTests/MvcSandboxTest.cs

@@ -29,7 +29,7 @@ public async Task Home_Pages_ReturnSuccess()
         public async Task RazorPages_ReturnSuccess()
         {
             // Arrange & Act
-            var response = await Client.GetStringAsync("http://localhost/Pages/");
+            var response = await Client.GetStringAsync("http://localhost/PagesHome");
 
             // Assert
             Assert.Contains("This file should give you a quick view of a Mvc Razor Page in action.", response);

test/Microsoft.AspNetCore.Mvc.RazorPages.Test/Internal/RazorPagesOptionsSetupTest.cs

@@ -29,5 +29,19 @@ public void Configure_AddsGlobalFilters()
                 filter => Assert.IsType<PageSaveTempDataPropertyFilterFactory>(filter),
                 filter => Assert.IsType<AutoValidateAntiforgeryTokenAttribute>(filter));
         }
+
+        [Fact]
+        public void Configure_SetsRazorPagesRoot()
+        {
+            // Arrange
+            var options = new RazorPagesOptions();
+            var setup = new RazorPagesOptionsSetup();
+
+            // Act
+            setup.Configure(options);
+
+            // Assert
+            Assert.Equal("/Pages", options.RootDirectory);
+        }
     }
 }

test/WebSites/RazorPagesWebSite/Startup.cs

@@ -19,7 +19,8 @@ public void ConfigureServices(IServiceCollection services)
                     options.AuthorizePage("/HelloWorldWithAuth");
                     options.AuthorizeFolder("/Pages/Admin");
                     options.AllowAnonymousToPage("/Pages/Admin/Login");
-                });
+                })
+                .WithRazorPagesAtContentRoot();
         }
 
         public void Configure(IApplicationBuilder app)

test/WebSites/RazorPagesWebSite/StartupWithBasePath.cs

@@ -16,7 +16,6 @@ public void ConfigureServices(IServiceCollection services)
                 .AddCookieTempDataProvider()
                 .AddRazorPagesOptions(options =>
                 {
-                    options.RootDirectory = "/Pages";
                     options.AuthorizePage("/Conventions/Auth");
                     options.AuthorizeFolder("/Conventions/AuthFolder");
                 });