redirect to external privacy link (#9347)

* Redirect privacy to external Microsoft privacy

Author: lyndaidaii

src/NuGetGallery/Controllers/PagesController.cs

@@ -152,6 +152,11 @@ public virtual async Task<ActionResult> Terms()
         [HttpGet]
         public virtual async Task<ActionResult> Privacy()
         {
+            if (!String.IsNullOrEmpty(Url.ExternalPrivacyUrl()))
+            {
+                return Redirect(Url.ExternalPrivacyUrl());
+            }
+
             if (_contentService != null)
             {
                 ViewBag.Content = await _contentService.GetContentItemAsync(

src/NuGetGallery/UrlHelperExtensions.cs

@@ -1412,6 +1412,11 @@ public static string Privacy(this UrlHelper url, bool relativeUrl = true)
             return GetActionLink(url, "Privacy", "Pages", relativeUrl);
         }
 
+        public static string ExternalPrivacyUrl(this UrlHelper url)
+        {
+            return _configuration.Current.ExternalPrivacyPolicyUrl;
+        }
+
         public static string About(this UrlHelper url, bool relativeUrl = true)
         {
             if (!String.IsNullOrEmpty(_configuration.Current.ExternalAboutUrl))

tests/NuGetGallery.Facts/Controllers/PagesControllerFacts.cs

@@ -1,12 +1,14 @@
 // 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.Threading.Tasks;
 using System.Web;
 using Moq;
 using NuGet.Services.Entities;
 using NuGet.Services.Messaging.Email;
 using NuGetGallery.Areas.Admin;
+using NuGetGallery.Configuration;
 using NuGetGallery.Framework;
 using NuGetGallery.Infrastructure.Mail.Messages;
 using NuGetGallery.ViewModels;
@@ -88,6 +90,41 @@ public async Task HtmlEncodesTheSupportRequest()
                         It.IsAny<User>(),
                         It.IsAny<Package>()));
             }
+
+            [Fact]
+            public async Task WithExternalPrivacyUrlConfigured()
+            {
+                var externalPrivacyUrl = "https://privacy.microsoft.com";
+                var configuration = GetConfigurationService();
+                var pagesController = GetController<PagesController>();
+
+                configuration.Current.ExternalPrivacyPolicyUrl = externalPrivacyUrl;
+
+                var result = await pagesController.Privacy();
+
+                GetMock<IContentService>()
+                    .Verify(m => m.GetContentItemAsync(
+                        It.IsAny<string>(),
+                        It.IsAny<TimeSpan>()), Times.Never);
+
+            }
+
+            [Fact]
+            public async Task WithoutExternalPrivacyUrlConfigured()
+            {
+                var externalPrivacyUrl = "";
+                var configuration = GetConfigurationService();
+                var pagesController = GetController<PagesController>();
+
+                configuration.Current.ExternalPrivacyPolicyUrl = externalPrivacyUrl;
+
+                var result = await pagesController.Privacy();
+
+                GetMock<IContentService>()
+                    .Verify(m => m.GetContentItemAsync(
+                        It.IsAny<string>(),
+                        It.IsAny<TimeSpan>()), Times.Once);
+            }
         }
     }
 }

tests/NuGetGallery.Facts/UrlHelperExtensionsFacts.cs

@@ -276,6 +276,23 @@ public void UsesConfiguredSiteRootInAbsoluteUri(
             }
         }
 
+        public class GetExternalPrivacyUrlMethod : TestContainer
+        {
+            [Theory]
+            [InlineData("")]
+            [InlineData("https://privacy.microsoft.com")]
+            public void VerifyExternalPrivacyUrlMethod(string expectedUrl) {
+                var configurationService = GetConfigurationService();
+                configurationService.Current.ExternalPrivacyPolicyUrl = expectedUrl;
+
+                var urlHelper = TestUtility.MockUrlHelper(expectedUrl);
+
+                var result = UrlHelperExtensions.ExternalPrivacyUrl(TestUtility.MockUrlHelper());
+
+                Assert.Equal(expectedUrl, result);  
+            }
+        }
+
         public class TheGetActionLinkMethod : TestContainer
         {
             public static IEnumerable<object[]> GeneratesTheCorrectActionLink_Data