Refactor error handling: replace 404 page with a reusable ErrorPageComponent and update routing logic

Author: neozhu

src/Server.UI/Components/Routes.razor

@@ -2,7 +2,7 @@
 @inject LayoutService LayoutService
 
 <CascadingAuthenticationState>
-    <Router AppAssembly="@typeof(Program).Assembly">
+    <Router AppAssembly="@typeof(Program).Assembly" NotFoundPage="typeof(Pages.NotFound)">
         <Found Context="routeData">
             <AuthorizeRouteView RouteData="@routeData" DefaultLayout="@typeof(MainLayout)">
                 <Authorizing>

src/Server.UI/Components/Shared/ErrorPageComponent.razor

@@ -0,0 +1,133 @@
+@inject IStringLocalizer<ErrorPageComponent> L
+@inject IJSRuntime JSRuntime
+
+<div style="display: flex; justify-content: center; align-items: center; min-height: @MinHeight; padding: 2rem;">
+    <MudPaper Class="pa-8" Elevation="1" Style="max-width: 500px; text-align: center;">
+        
+
+        <MudText Typo="Typo.h3" Class="mb-2" Style="font-weight: 300;">
+            @ErrorCode
+        </MudText>
+        
+        <MudText Typo="Typo.h6" Class="mb-4" Color="Color.Default">
+            @Title
+        </MudText>
+        
+        <MudText Typo="Typo.body1" Class="mb-6" Color="Color.Secondary" Style="line-height: 1.5;">
+            @Description
+        </MudText>
+        
+        <MudStack Row Justify="Justify.Center" Spacing="2">
+            @if (ShowHomeButton)
+            {
+                <MudButton Variant="Variant.Filled" 
+                          Color="Color.Primary" 
+                          StartIcon="@Icons.Material.Filled.Home"
+                          Href="/">
+                    @L["Return Home"]
+                </MudButton>
+            }
+            
+            @if (ShowBackButton)
+            {
+                <MudButton Variant="Variant.Outlined" 
+                          Color="Color.Primary" 
+                          StartIcon="@Icons.Material.Filled.ArrowBack"
+                          OnClick="GoBack">
+                    @L["Go Back"]
+                </MudButton>
+            }
+            
+            @if (ShowContactButton)
+            {
+                <MudButton Variant="Variant.Outlined" 
+                          Color="Color.Primary" 
+                          StartIcon="@Icons.Material.Filled.ContactSupport"
+                          OnClick="OnContactClick">
+                    @ContactButtonText
+                </MudButton>
+            }
+        </MudStack>
+        
+    </MudPaper>
+</div>
+
+@code {
+    [Parameter] public string ErrorCode { get; set; } = "404";
+    [Parameter] public string Title { get; set; } = "";
+    [Parameter] public string Description { get; set; } = "";
+    [Parameter] public string MinHeight { get; set; } = "60vh";
+    [Parameter] public bool ShowHomeButton { get; set; } = true;
+    [Parameter] public bool ShowBackButton { get; set; } = false;
+    [Parameter] public bool ShowContactButton { get; set; } = false;
+    [Parameter] public string ContactButtonText { get; set; } = "";
+    [Parameter] public EventCallback OnContactClick { get; set; }
+    [Parameter] public ErrorType Type { get; set; } = ErrorType.NotFound;
+
+    public enum ErrorType
+    {
+        NotFound,
+        AccessDenied,
+        ServerError,
+        Custom
+    }
+
+    protected override void OnInitialized()
+    {
+        // Set defaults based on error type if not explicitly provided
+        if (string.IsNullOrEmpty(Title))
+        {
+            Title = Type switch
+            {
+                ErrorType.AccessDenied => L["Access Denied"],
+                ErrorType.ServerError => L["Server Error"],
+                _ => L["Page Not Found"]
+            };
+        }
+
+        if (string.IsNullOrEmpty(Description))
+        {
+            Description = Type switch
+            {
+                ErrorType.AccessDenied => L["You don't have permission to access this resource. If you believe this is an error, please contact your administrator."],
+                ErrorType.ServerError => L["An unexpected error occurred. Please try again later."],
+                _ => L["The page you're looking for doesn't exist or has been moved. Please verify the URL and try again."]
+            };
+        }
+
+        if (string.IsNullOrEmpty(ContactButtonText))
+        {
+            ContactButtonText = Type == ErrorType.AccessDenied ? L["Contact Administrator"] : L["Contact Support"];
+        }
+
+        if (Type == ErrorType.AccessDenied)
+        {
+            ErrorCode = "403";
+        }
+    }
+
+    private string GetErrorIcon()
+    {
+        return Type switch
+        {
+            ErrorType.AccessDenied => Icons.Material.Filled.NoAccounts,
+            ErrorType.ServerError => Icons.Material.Filled.Error,
+            _ => Icons.Material.Filled.SearchOff
+        };
+    }
+
+    private Color GetErrorColor()
+    {
+        return Type switch
+        {
+            ErrorType.AccessDenied => Color.Warning,
+            ErrorType.ServerError => Color.Error,
+            _ => Color.Error
+        };
+    }
+
+    private async Task GoBack()
+    {
+        await JSRuntime.InvokeVoidAsync("history.back");
+    }
+} 

src/Server.UI/DependencyInjection.cs

@@ -137,7 +137,7 @@ public static WebApplication ConfigureServer(this WebApplication app, IConfigura
             app.UseHsts();
         }
         app.InitializeCacheFactory();
-        app.UseStatusCodePagesWithRedirects("/404");
+        app.UseStatusCodePagesWithReExecute("/not-found",createScopeForStatusCodePages: true);
         app.MapHealthChecks("/health");
         app.UseAuthentication();
         app.UseAuthorization();

src/Server.UI/Pages/404.razor

@@ -0,0 +1,34 @@
+@page "/not-found"
+
+@inject NavigationManager Navigation
+@inject AuthenticationStateProvider AuthenticationStateProvider
+@using CleanArchitecture.Blazor.Server.UI.Components.Shared
+
+<PageTitle>@ApplicationSettings.AppName - Page Not Found - 404</PageTitle>
+
+<ErrorPageComponent Type="@_errorType" 
+                   MinHeight="80vh" 
+                   ShowBackButton="true" />
+
+@code {
+    private ErrorPageComponent.ErrorType _errorType = ErrorPageComponent.ErrorType.NotFound;
+
+    protected override async Task OnInitializedAsync()
+    {
+        var currentPath = Navigation.ToBaseRelativePath(Navigation.Uri);
+        var authState = await AuthenticationStateProvider.GetAuthenticationStateAsync();
+        var isAuthenticated = authState.User?.Identity?.IsAuthenticated ?? false;
+        
+        // Simple check: if user is authenticated and path contains admin-like keywords
+        if (isAuthenticated && IsLikelyProtectedPath(currentPath))
+        {
+            _errorType = ErrorPageComponent.ErrorType.AccessDenied;
+        }
+    }
+
+    private bool IsLikelyProtectedPath(string path)
+    {
+        var protectedPaths = new[] { "admin", "management", "system", "users", "tenants", "roles", "audit" };
+        return protectedPaths.Any(p => path.Contains(p, StringComparison.OrdinalIgnoreCase));
+    }
+}