Enhance error handling UI and middleware in ASP.NET

Updated `Error.razor` to provide distinct 404 and 500 error messages with a user-friendly layout, including a home button. Conditionally rendered Request ID display and removed development mode information for a cleaner user experience.

Modified `Program.cs` to change error handling middleware from re-executing the error page to redirecting with error codes, improving error information passed to the error page.

SqlDatabaseVectorSearch/Components/Pages/Error.razor

@@ -1,33 +1,49 @@
 @page "/Error"
 @using System.Diagnostics
+@rendermode @(new InteractiveServerRenderMode(prerender: false))
 
-<PageTitle>Error</PageTitle>
+<div class="d-flex align-items-center justify-content-center">
+    <div class="text-center">
+        @if (Code == 404)
+        {
+            <PageTitle>Page Not Found</PageTitle>
 
-<h1 class="text-danger">Error.</h1>
-<h2 class="text-danger">An error occurred while processing your request.</h2>
+            <h1 class="display-1 fw-bold">404</h1>
+            <p class="fs-3"><span class="text-danger">Ops!</span> Page Not Found.</p>
+            <p class="lead">
+                The page you're looking for does not exists.
+            </p>
+        }
+        else
+        {
+            <PageTitle>Unexpected Error</PageTitle>
 
-@if (ShowRequestId)
-{
+            <h1 class="display-1 fw-bold">500</h1>
+            <p class="fs-3"><span class="text-danger">Ops!</span> Unexpected error.</p>
+            <p class="lead">
+                An unexpected error occurred while loading the page. Please, wait a minute and try again.
+            </p>
+        }
+
+        <a title="Back to Home" href="/" class="btn btn-primary"><i class="bi bi-house-door-fill"></i> Back to Home</a>
+
+        @if (ShowRequestId)
+        {
             <p>
                 <strong>Request ID:</strong> <code>@RequestId</code>
             </p>
-}
+        }
+    </div>
+</div>
 
-<h3>Development Mode</h3>
-<p>
-    Swapping to <strong>Development</strong> environment will display more detailed information about the error that occurred.
-</p>
-<p>
-    <strong>The Development environment shouldn't be enabled for deployed applications.</strong>
-    It can result in displaying sensitive information from exceptions to end users.
-    For local debugging, enable the <strong>Development</strong> environment by setting the <strong>ASPNETCORE_ENVIRONMENT</strong> environment variable to <strong>Development</strong>
-    and restarting the app.
-</p>
-
-@code{
+@code {
     [CascadingParameter]
     private HttpContext? HttpContext { get; set; }
 
+    [Parameter]
+    [SupplyParameterFromQuery(Name = "code")]
+    public int Code { get; set; }
+
     private string? RequestId { get; set; }
     private bool ShowRequestId => !string.IsNullOrEmpty(RequestId);
 

SqlDatabaseVectorSearch/Program.cs

@@ -101,7 +101,7 @@ app.UseWhen(context => context.IsWebRequest(), builder =>
         builder.UseHsts();
     }
 
-    builder.UseStatusCodePagesWithReExecute("/error");
+    builder.UseStatusCodePagesWithRedirects("/error?code={0}");
 });
 
 app.UseWhen(context => context.IsApiRequest(), builder =>