RedirectToPage from a form-action handler includes the formaction

Fixes #6104

src/Microsoft.AspNetCore.Mvc.RazorPages/PageUrlHelperExtensions.cs

@@ -89,9 +89,9 @@ namespace Microsoft.AspNetCore.Mvc
             }
 
             var routeValues = new RouteValueDictionary(values);
+            var ambientValues = urlHelper.ActionContext.RouteData.Values;
             if (pageName == null)
             {
-                var ambientValues = urlHelper.ActionContext.RouteData.Values;
                 if (!routeValues.ContainsKey("page") &&
                     ambientValues.TryGetValue("page", out var value))
                 {
@@ -103,6 +103,13 @@ namespace Microsoft.AspNetCore.Mvc
                 routeValues["page"] = pageName;
             }
 
+            if (!routeValues.ContainsKey("formaction") && 
+                ambientValues.TryGetValue("formaction", out var formaction))
+            {
+                // Clear out formaction unless it's explicitly specified in the routeValues.
+                routeValues["formaction"] = null;
+            }
+
             return urlHelper.RouteUrl(
                 routeName: null,
                 values: routeValues,

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

@@ -763,6 +763,34 @@ Microsoft.AspNetCore.Mvc.ViewFeatures.ViewDataDictionary`1[AspNetCore._InjectedP
             Assert.Equal(expected, response.Headers.Location.ToString());
         }
 
+        [Fact]
+        public async Task RedirectDoesNotIncludeFormActionByDefault()
+        {
+            // Arrange
+            var expected = "/Pages/Redirects/RedirectFromFormActionHandler";
+
+            // Act
+            var response = await Client.GetAsync("/Pages/Redirects/RedirectFromFormActionHandler/RedirectToPage/10");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.Redirect, response.StatusCode);
+            Assert.Equal(expected, response.Headers.Location.ToString());
+        }
+
+        [Fact]
+        public async Task RedirectToOtherHandlersWorks()
+        {
+            // Arrange
+            var expected = "/Pages/Redirects/RedirectFromFormActionHandler/RedirectToPage/11";
+
+            // Act
+            var response = await Client.GetAsync("/Pages/Redirects/RedirectFromFormActionHandler/RedirectToAnotherHandler/11");
+
+            // Assert
+            Assert.Equal(HttpStatusCode.Redirect, response.StatusCode);
+            Assert.Equal(expected, response.Headers.Location.ToString());
+        }
+
         private async Task AddAntiforgeryHeaders(HttpRequestMessage request)
         {
             var getResponse = await Client.GetAsync(request.RequestUri);

test/Microsoft.AspNetCore.Mvc.RazorPages.Test/PageUrlHelperExtensionsTest.cs

@@ -27,9 +27,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             {
                 RouteData = routeData,
             };
-            var urlHelper = new Mock<IUrlHelper>();
-            urlHelper.SetupGet(h => h.ActionContext)
-                .Returns(actionContext);
+            var urlHelper = CreateUrlHelper(actionContext);
             urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
                 .Callback((UrlRouteContext context) => actual = context);
 
@@ -77,7 +75,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
         {
             // Arrange
             UrlRouteContext actual = null;
-            var urlHelper = new Mock<IUrlHelper>();
+            var urlHelper = CreateUrlHelper();
             urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
                 .Callback((UrlRouteContext context) => actual = context);
 
@@ -109,7 +107,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
         {
             // Arrange
             UrlRouteContext actual = null;
-            var urlHelper = new Mock<IUrlHelper>();
+            var urlHelper = CreateUrlHelper();
             urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
                 .Callback((UrlRouteContext context) => actual = context);
 
@@ -141,7 +139,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
         {
             // Arrange
             UrlRouteContext actual = null;
-            var urlHelper = new Mock<IUrlHelper>();
+            var urlHelper = CreateUrlHelper();
             urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
                 .Callback((UrlRouteContext context) => actual = context);
 
@@ -173,7 +171,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
         {
             // Arrange
             UrlRouteContext actual = null;
-            var urlHelper = new Mock<IUrlHelper>();
+            var urlHelper = CreateUrlHelper();
             urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
                 .Callback((UrlRouteContext context) => actual = context);
 
@@ -217,9 +215,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
                 RouteData = routeData,
             };
 
-            var urlHelper = new Mock<IUrlHelper>();
-            urlHelper.SetupGet(p => p.ActionContext)
-                .Returns(actionContext);
+            var urlHelper = CreateUrlHelper(actionContext);
             urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
                 .Callback((UrlRouteContext context) => actual = context);
 
@@ -246,5 +242,112 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             Assert.Equal("mytesthost", actual.Host);
             Assert.Equal("#toc", actual.Fragment);
         }
+
+        [Fact]
+        public void Page_SetsFormActionToNull_IfValueIsNotSpecifiedInRouteValues()
+        {
+            // Arrange
+            UrlRouteContext actual = null;
+            var routeData = new RouteData
+            {
+                Values =
+                {
+                    { "page", "ambient-page" },
+                    { "formaction", "ambient-formaction" },
+                }
+            };
+            var actionContext = new ActionContext
+            {
+                RouteData = routeData,
+            };
+
+            var urlHelper = CreateUrlHelper(actionContext);
+            urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
+                .Callback((UrlRouteContext context) => actual = context);
+
+            // Act
+            string page = null;
+            urlHelper.Object.Page(page, new { id = 13 }, "https", "mytesthost", "#toc");
+
+            // Assert
+            urlHelper.Verify();
+            Assert.NotNull(actual);
+            Assert.Null(actual.RouteName);
+            Assert.Collection(Assert.IsType<RouteValueDictionary>(actual.Values),
+                value =>
+                {
+                    Assert.Equal("id", value.Key);
+                    Assert.Equal(13, value.Value);
+                },
+                value =>
+                {
+                    Assert.Equal("page", value.Key);
+                    Assert.Equal("ambient-page", value.Value);
+                },
+                value =>
+                {
+                    Assert.Equal("formaction", value.Key);
+                    Assert.Null(value.Value);
+                });
+        }
+
+        [Fact]
+        public void Page_UsesExplicitlySpecifiedFormActionValue()
+        {
+            // Arrange
+            UrlRouteContext actual = null;
+            var routeData = new RouteData
+            {
+                Values =
+                {
+                    { "page", "ambient-page" },
+                    { "formaction", "ambient-formaction" },
+                }
+            };
+            var actionContext = new ActionContext
+            {
+                RouteData = routeData,
+            };
+
+            var urlHelper = CreateUrlHelper(actionContext);
+            urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
+                .Callback((UrlRouteContext context) => actual = context);
+
+            // Act
+            string page = null;
+            urlHelper.Object.Page(page, new { formaction = "exact-formaction" }, "https", "mytesthost", "#toc");
+
+            // Assert
+            urlHelper.Verify();
+            Assert.NotNull(actual);
+            Assert.Null(actual.RouteName);
+            Assert.Collection(Assert.IsType<RouteValueDictionary>(actual.Values),
+                value =>
+                {
+                    Assert.Equal("formaction", value.Key);
+                    Assert.Equal("exact-formaction", value.Value);
+                },
+                value =>
+                {
+                    Assert.Equal("page", value.Key);
+                    Assert.Equal("ambient-page", value.Value);
+                });
+        }
+
+        private static Mock<IUrlHelper> CreateUrlHelper(ActionContext context = null)
+        {
+            if (context == null)
+            {
+                context = new ActionContext
+                {
+                    RouteData = new RouteData(),
+                };
+            }
+
+            var urlHelper = new Mock<IUrlHelper>();
+            urlHelper.SetupGet(h => h.ActionContext)
+                .Returns(context);
+            return urlHelper;
+        }
     }
 }

test/Microsoft.AspNetCore.Mvc.RazorPages.Test/RedirectToPageResultTest.cs

@@ -32,7 +32,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
 
             var actionContext = new ActionContext(httpContext, new RouteData(), new ActionDescriptor());
 
-            var urlHelper = GetUrlHelper(returnValue: null);
+            var urlHelper = GetUrlHelper(actionContext, returnValue: null);
             var result = new RedirectToPageResult("some-page", new Dictionary<string, object>())
             {
                 UrlHelper = urlHelper,
@@ -64,7 +64,7 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
                 new RouteData(),
                 new ActionDescriptor());
 
-            var urlHelper = GetUrlHelper(expectedUrl);
+            var urlHelper = GetUrlHelper(actionContext, expectedUrl);
             var result = new RedirectToPageResult("MyPage", new { id = 10, test = "value" }, permanentRedirect)
             {
                 UrlHelper = urlHelper,
@@ -89,10 +89,12 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             var pageContext = new PageContext
             {
                 HttpContext = httpContext,
+                RouteData = new RouteData(),
             };
 
             UrlRouteContext context = null;
             var urlHelper = new Mock<IUrlHelper>();
+            urlHelper.SetupGet(h => h.ActionContext).Returns(pageContext);
             urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
                 .Callback((UrlRouteContext c) => context = c)
                 .Returns("some-value");
@@ -174,6 +176,62 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
                });
         }
 
+        [Fact]
+        public async Task RedirectToPage_DoesNotUseAmbientFormAction()
+        {
+            // Arrange
+            var expected = "path/to/this-page";
+            var httpContext = new Mock<HttpContext>();
+            var httpResponse = new Mock<HttpResponse>();
+            httpContext.SetupGet(c => c.Response)
+                .Returns(httpResponse.Object);
+            httpContext.SetupGet(c => c.RequestServices)
+                .Returns(CreateServices());
+            var routeData = new RouteData
+            {
+                Values =
+                {
+                    ["page"] = expected,
+                    ["formaction"] = "delete",
+                }
+            };
+
+            var actionContext = new ActionContext(
+                httpContext.Object,
+                routeData,
+                new ActionDescriptor());
+
+            UrlRouteContext context = null;
+            var urlHelper = new Mock<IUrlHelper>();
+            urlHelper.Setup(h => h.RouteUrl(It.IsAny<UrlRouteContext>()))
+                .Callback((UrlRouteContext c) => context = c)
+                .Returns("some-value");
+            urlHelper.SetupGet(h => h.ActionContext)
+                .Returns(actionContext);
+            var pageName = (string)null;
+            var result = new RedirectToPageResult(pageName)
+            {
+                UrlHelper = urlHelper.Object,
+            };
+
+            // Act
+            await result.ExecuteResultAsync(actionContext);
+
+            // Assert
+            Assert.NotNull(context);
+            Assert.Collection(Assert.IsType<RouteValueDictionary>(context.Values),
+               value =>
+               {
+                   Assert.Equal("page", value.Key);
+                   Assert.Equal(expected, value.Value);
+               },
+               value =>
+               {
+                   Assert.Equal("formaction", value.Key);
+                   Assert.Null(value.Value);
+               });
+        }
+
         private static IServiceProvider CreateServices(IUrlHelperFactory factory = null)
         {
             var services = new ServiceCollection();
@@ -192,9 +250,10 @@ namespace Microsoft.AspNetCore.Mvc.RazorPages
             return services.BuildServiceProvider();
         }
 
-        private static IUrlHelper GetUrlHelper(string returnValue)
+        private static IUrlHelper GetUrlHelper(ActionContext context, string returnValue)
         {
             var urlHelper = new Mock<IUrlHelper>();
+            urlHelper.SetupGet(h => h.ActionContext).Returns(context);
             urlHelper.Setup(o => o.RouteUrl(It.IsAny<UrlRouteContext>())).Returns(returnValue);
             return urlHelper.Object;
         }

test/WebSites/RazorPagesWebSite/Pages/Redirects/RedirectFromFormActionHandler.cshtml

@@ -0,0 +1,13 @@
+@page "{formaction?}/{id:int?}"
+@functions
+{
+    public IActionResult OnGetRedirectToPage(int id)
+    {
+        return RedirectToPage();
+    }
+
+    public IActionResult OnGetRedirectToAnotherHandler(int id)
+    {
+        return RedirectToPage(new { formaction = "RedirectToPage", id = id });
+    }
+}