Fix client navigation: always use enhanced nav for not found rendering, unless user explicitly disbled it.

Author: ilonatommy

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.Streaming.cs

@@ -229,23 +229,24 @@ private static void HandleExceptionAfterResponseStarted(HttpContext httpContext,
     private static void HandleNotFoundAfterResponseStarted(TextWriter writer, HttpContext httpContext, string notFoundUrl)
     {
         writer.Write("<blazor-ssr><template type=\"not-found\"");
-        WriteResponseTemplate(writer, httpContext, notFoundUrl);
+        WriteResponseTemplate(writer, httpContext, notFoundUrl, useEnhancedNav: true);
     }
 
     private static void HandleNavigationAfterResponseStarted(TextWriter writer, HttpContext httpContext, string destinationUrl)
     {
         writer.Write("<blazor-ssr><template type=\"redirection\"");
-        WriteResponseTemplate(writer, httpContext, destinationUrl);
+        bool useEnhancedNav = IsProgressivelyEnhancedNavigation(httpContext.Request);
+        WriteResponseTemplate(writer, httpContext, destinationUrl, useEnhancedNav);
     }
 
-    private static void WriteResponseTemplate(TextWriter writer, HttpContext httpContext, string destinationUrl)
+    private static void WriteResponseTemplate(TextWriter writer, HttpContext httpContext, string destinationUrl, bool useEnhancedNav)
     {
         if (HttpMethods.IsPost(httpContext.Request.Method))
         {
             writer.Write(" from=\"form-post\"");
         }
 
-        if (IsProgressivelyEnhancedNavigation(httpContext.Request))
+        if (useEnhancedNav)
         {
             writer.Write(" enhanced=\"true\"");
         }

src/Components/Web.JS/src/Rendering/StreamingRendering.ts

@@ -45,12 +45,16 @@ class BlazorStreamingUpdate extends HTMLElement {
             insertStreamingContentIntoDocument(componentId, node.content);
           }
         } else {
+          const isEnhancedNav = node.getAttribute('enhanced') === 'true';
           switch (node.getAttribute('type')) {
             case 'redirection':
-              redirect(node, true);
+              redirect(node, true, isEnhancedNav);
               break;
             case 'not-found':
-              redirect(node, false);
+              // not-found template has enhanced nav set to true by default,
+              // check for the options to avoid overriding user settings
+              const useEnhancedNav = isEnhancedNav && enableDomPreservation;
+              redirect(node, false, useEnhancedNav);
               break;
             case 'error':
               // This is kind of brutal but matches what happens without progressive enhancement
@@ -63,12 +67,11 @@ class BlazorStreamingUpdate extends HTMLElement {
   }
 }
 
-function redirect(node: HTMLTemplateElement, changeUrl: boolean): void {
+function redirect(node: HTMLTemplateElement, changeUrl: boolean, isEnhancedNav: boolean): void {
   // We use 'replace' here because it's closest to the non-progressively-enhanced behavior, and will make the most sense
  // if the async delay was very short, as the user would not perceive having been on the intermediate page.
  const destinationUrl = toAbsoluteUri(node.content.textContent!);
  const isFormPost = node.getAttribute('from') === 'form-post';
- const isEnhancedNav = node.getAttribute('enhanced') === 'true';
  if (isEnhancedNav && isWithinBaseUriSpace(destinationUrl)) {
    // At this point the destinationUrl might be an opaque URL so we don't know whether it's internal/external or
    // whether it's even going to the same URL we're currently on. So we don't know how to update the history.

src/Components/test/E2ETest/ServerRenderingTests/NoInteractivityTest.cs

@@ -127,16 +127,11 @@ private void AssertNotFoundPageRendered()
     private void AssertUrlNotChanged(string expectedUrl) =>
         Browser.True(() => Browser.Url.Contains(expectedUrl), $"Expected URL to contain '{expectedUrl}', but found '{Browser.Url}'");
 
-    private void AssertUrlChanged(string urlPart) =>
-        Browser.False(() => Browser.Url.Contains(urlPart), $"Expected URL not to contain '{urlPart}', but found '{Browser.Url}'");
-
     [Theory]
     [InlineData(true, true)]
     [InlineData(true, false)]
     [InlineData(false, true)]
     [InlineData(false, false)]
-    // When response has not started, it does not matter how we arrive the the page setting the not found status code.
-    // We can navigate straight to the testing page, skipping the index page.
     public void NotFoundSetOnInitialization_ResponseNotStarted_SSR(bool hasReExecutionMiddleware, bool hasCustomNotFoundPageSet)
     {
         string reexecution = hasReExecutionMiddleware ? "/reexecution" : "";
@@ -154,32 +149,18 @@ public void NotFoundSetOnInitialization_ResponseNotStarted_SSR(bool hasReExecuti
         AssertUrlNotChanged(testUrl);
     }
 
-    // If the response has started, it matters how we arrive the the page setting the not found status code
-    // because we are rendering client-side. In browser-initiated navigation and form submissions, the headers
-    // don't contain enhanced-nav and we redirect to the not found page. In link clicking navigation,
-    // the headers contain enhanced-nav, redirection is not needed and the original url is preserved.
-
     [Theory]
     [InlineData(true, true)]
     [InlineData(true, false)]
     [InlineData(false, true)]
     [InlineData(false, false)]
-    // enhanced navigation is switched off for browser navigation
     public void NotFoundSetOnInitialization_ResponseStarted_BrowserNavigation_SSR(bool hasReExecutionMiddleware, bool hasCustomNotFoundPageSet)
     {
         string reexecution = hasReExecutionMiddleware ? "/reexecution" : "";
         string testUrl = $"{ServerPathBase}{reexecution}/set-not-found-ssr-streaming?useCustomNotFoundPage={hasCustomNotFoundPageSet}";
         Navigate(testUrl);
         AssertNotFoundRendered_ResponseStarted_Or_POST(hasReExecutionMiddleware, hasCustomNotFoundPageSet, testUrl);
-        bool throwsException = !hasCustomNotFoundPageSet && !hasReExecutionMiddleware;
-        if (throwsException)
-        {
-            AssertUrlNotChanged(testUrl);
-        }
-        else
-        {
-            AssertUrlChanged(testUrl);
-        }
+        AssertUrlNotChanged(testUrl);
     }
 
     private void AssertNotFoundRendered_ResponseStarted_Or_POST(bool hasReExecutionMiddleware, bool hasCustomNotFoundPageSet, string testUrl)
@@ -204,7 +185,6 @@ private void AssertNotFoundRendered_ResponseStarted_Or_POST(bool hasReExecutionM
     [InlineData(true, false)]
     [InlineData(false, true)]
     [InlineData(false, false)]
-    // enhanced navigation is switched on for link navigation
     public void NotFoundSetOnInitialization_ResponseStarted_LinkNavigation_SSR(bool hasReExecutionMiddleware, bool hasCustomNotFoundPageSet)
     {
         string testUrl = NavigateByLinkToPageTestingNotFound("Sets", hasReExecutionMiddleware, hasCustomNotFoundPageSet);
@@ -229,8 +209,6 @@ private string NavigateByLinkToPageTestingNotFound(string action, bool hasReExec
     [InlineData(true, false)]
     [InlineData(false, true)]
     [InlineData(false, false)]
-    // NotFound triggered by POST cannot get rendered in the same batch and we rely on the client to render it
-    // However, because it is triggered by form POST, it won't have enhanced-nav headers
     public void NotFoundSetOnFormSubmit_ResponseNotStarted_SSR(bool hasReExecutionMiddleware, bool hasCustomNotFoundPageSet)
     {
         string reexecution = hasReExecutionMiddleware ? "/reexecution" : "";
@@ -239,15 +217,7 @@ public void NotFoundSetOnFormSubmit_ResponseNotStarted_SSR(bool hasReExecutionMi
         Browser.FindElement(By.Id("not-found-form")).FindElement(By.TagName("button")).Click();
 
         AssertNotFoundRendered_ResponseStarted_Or_POST(hasReExecutionMiddleware, hasCustomNotFoundPageSet, testUrl);
-        bool throwsException = !hasCustomNotFoundPageSet && !hasReExecutionMiddleware;
-        if (throwsException)
-        {
-            AssertUrlNotChanged(testUrl);
-        }
-        else
-        {
-            AssertUrlChanged(testUrl);
-        }
+        AssertUrlNotChanged(testUrl);
     }
 
     [Theory]
@@ -263,15 +233,7 @@ public void NotFoundSetOnFormSubmit_ResponseStarted_SSR(bool hasReExecutionMiddl
         Browser.FindElement(By.Id("not-found-form")).FindElement(By.TagName("button")).Click();
 
         AssertNotFoundRendered_ResponseStarted_Or_POST(hasReExecutionMiddleware, hasCustomNotFoundPageSet, testUrl);
-        bool throwsException = !hasCustomNotFoundPageSet && !hasReExecutionMiddleware;
-        if (throwsException)
-        {
-            AssertUrlNotChanged(testUrl);
-        }
-        else
-        {
-            AssertUrlChanged(testUrl);
-        }
+        AssertUrlNotChanged(testUrl);
     }
 
     private void AssertNotFoundFragmentRendered() =>

src/Shared/E2ETesting/WaitAssert.cs

@@ -40,9 +40,6 @@ public static void True(this IWebDriver driver, Func<bool> actual, TimeSpan time
     public static void True(this IWebDriver driver, Func<bool> actual, string message)
         => WaitAssertCore(driver, () => Assert.True(actual(), message));
 
-    public static void False(this IWebDriver driver, Func<bool> actual, string message)
-        => WaitAssertCore(driver, () => Assert.False(actual(), message));
-
     public static void False(this IWebDriver driver, Func<bool> actual)
         => WaitAssertCore(driver, () => Assert.False(actual()));