feat: Implement URL-based culture handling in Blazor and MVC requests

framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Localization/AbpCultureMenuItemUrlProvider.cs

@@ -54,10 +54,10 @@ public class AbpCultureMenuItemUrlProvider : IMenuItemUrlProvider, ITransientDep
         var httpContext = HttpContextAccessor.HttpContext;
         if (httpContext != null)
         {
-            return httpContext.GetRouteValue("culture")?.ToString();
+            return AbpRequestCultureCookieHelper.GetRouteCulture(httpContext);
         }
 
-        // No HttpContext: Blazor interactive circuit or WASM client.
+        // No HttpContext: fallback to CurrentCulture.
         var currentCulture = CultureInfo.CurrentCulture.Name;
         var isKnownCulture = AbpLocalizationOptions.Value.Languages
             .Any(l => string.Equals(l.CultureName, currentCulture, StringComparison.OrdinalIgnoreCase));

framework/src/Volo.Abp.AspNetCore/Microsoft/AspNetCore/RequestLocalization/AbpRequestCultureCookieHelper.cs

@@ -1,11 +1,41 @@
 using System;
+using System.Globalization;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Localization;
+using Microsoft.AspNetCore.Routing;
 
 namespace Microsoft.AspNetCore.RequestLocalization;
 
 public static class AbpRequestCultureCookieHelper
 {
+    public const string HasRouteCultureCookieName = "Abp.HasRouteCulture";
+
+    /// <summary>
+    /// Gets the current route culture from the request. First checks route values,
+    /// then falls back to the HasRouteCulture cookie (set during Blazor SSR) with CurrentCulture.
+    /// Returns null if the request has no route-based culture.
+    /// </summary>
+    public static string? GetRouteCulture(HttpContext? httpContext)
+    {
+        if (httpContext == null)
+        {
+            return null;
+        }
+
+        var routeCulture = httpContext.GetRouteValue("culture")?.ToString();
+        if (!string.IsNullOrEmpty(routeCulture))
+        {
+            return routeCulture;
+        }
+
+        if (httpContext.Request.Cookies.ContainsKey(HasRouteCultureCookieName))
+        {
+            return CultureInfo.CurrentCulture.Name;
+        }
+
+        return null;
+    }
+
     public static void SetCultureCookie(
         HttpContext httpContext,
         RequestCulture requestCulture)
@@ -20,4 +50,21 @@ public static class AbpRequestCultureCookieHelper
             }
         );
     }
+
+    public static void SetHasRouteCultureCookie(HttpContext httpContext, bool hasRouteCulture)
+    {
+        if (hasRouteCulture)
+        {
+            httpContext.Response.Cookies.Append(
+                HasRouteCultureCookieName, "1",
+                new CookieOptions
+                {
+                    IsEssential = true
+                });
+        }
+        else
+        {
+            httpContext.Response.Cookies.Delete(HasRouteCultureCookieName);
+        }
+    }
 }

framework/src/Volo.Abp.AspNetCore/Microsoft/AspNetCore/RequestLocalization/AbpRequestLocalizationMiddleware.cs

@@ -1,4 +1,5 @@
-using System.Threading.Tasks;
+using System.Linq;
+using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Localization;
@@ -48,6 +49,17 @@ public class AbpRequestLocalizationMiddleware : AbpMiddlewareBase, ITransientDep
                         requestCultureFeature.RequestCulture
                     );
                 }
+
+                // Only manage HasRouteCulture cookie for Blazor component page requests.
+                // This cookie is used by AbpCultureMenuItemUrlProvider to determine if the
+                // initial SSR page had a culture prefix, since the Blazor interactive circuit
+                // (/_blazor) does not carry the original route values.
+                var endpoint = context.GetEndpoint();
+                if (endpoint?.Metadata.Any(m => m.GetType().Name == "ComponentTypeMetadata") == true)
+                {
+                    AbpRequestCultureCookieHelper.SetHasRouteCultureCookie(
+                        context, requestCultureFeature?.Provider is RouteDataRequestCultureProvider);
+                }
             }
 
             return Task.CompletedTask;

framework/test/Volo.Abp.AspNetCore.Mvc.Tests/Volo/Abp/AspNetCore/Mvc/Localization/AbpCultureMenuItemUrlProvider_Tests.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Globalization;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Http;
@@ -38,33 +39,51 @@ public class AbpCultureMenuItemUrlProvider_Tests
     }
 
     [Fact]
-    public async Task Should_Not_Add_Prefix_When_HttpContext_Has_No_Culture_Route()
+    public async Task Should_Not_Add_Prefix_For_Mvc_Request_Without_Culture()
     {
-        // HttpContext exists but has no {culture} route value (e.g. MVC request to /about).
-        // No prefix should be added to keep URL style consistent with the current page.
-        var provider = CreateProvider(useRouteBasedCulture: true, cultureName: null);
+        // MVC request to /about (no culture, no HasRouteCulture cookie).
+        var httpContext = new DefaultHttpContext();
+        httpContext.Request.RouteValues["controller"] = "Home";
+        httpContext.Request.RouteValues["action"] = "About";
+        var httpContextAccessor = new HttpContextAccessor { HttpContext = httpContext };
+        var localizationOptions = MsOptions.Create(
+            new AbpRequestLocalizationOptions { UseRouteBasedCulture = true });
+        var abpLocOptions = new AbpLocalizationOptions();
+        abpLocOptions.Languages.Add(new LanguageInfo("en"));
+        abpLocOptions.Languages.Add(new LanguageInfo("zh-Hans"));
+        var provider = new AbpCultureMenuItemUrlProvider(
+            httpContextAccessor, localizationOptions, MsOptions.Create(abpLocOptions));
+
         var menu = CreateMenuWithItems("/home", "/about");
 
-        await provider.HandleAsync(new MenuItemUrlProviderContext(menu));
+        var previousCulture = CultureInfo.CurrentCulture;
+        try
+        {
+            CultureInfo.CurrentCulture = new CultureInfo("zh-Hans");
+            await provider.HandleAsync(new MenuItemUrlProviderContext(menu));
+        }
+        finally
+        {
+            CultureInfo.CurrentCulture = previousCulture;
+        }
 
         menu.Items[0].Url.ShouldBe("/home");
         menu.Items[1].Url.ShouldBe("/about");
     }
 
     [Fact]
-    public async Task Should_Not_Add_Prefix_When_HttpContext_Has_No_Culture_Route_Even_With_Known_Languages()
+    public async Task Should_Fallback_To_CurrentCulture_In_Blazor_Circuit()
     {
-        // HttpContext exists but has no {culture} route value, even though CurrentCulture
-        // matches a known language. No prefix should be added because the current request
-        // does not have a culture segment in the URL.
-        var httpContext = new DefaultHttpContext(); // no culture route value
+        // Blazor Server interactive circuit: HttpContext exists (SignalR) but has
+        // no route culture. Cookie was set during SSR indicating route culture was used.
+        var httpContext = new DefaultHttpContext();
+        httpContext.Request.Headers["Cookie"] = $"{AbpRequestCultureCookieHelper.HasRouteCultureCookieName}=1";
         var httpContextAccessor = new HttpContextAccessor { HttpContext = httpContext };
         var localizationOptions = MsOptions.Create(
             new AbpRequestLocalizationOptions { UseRouteBasedCulture = true });
         var abpLocOptions = new AbpLocalizationOptions();
         abpLocOptions.Languages.Add(new LanguageInfo("en"));
         abpLocOptions.Languages.Add(new LanguageInfo("zh-Hans"));
-        abpLocOptions.Languages.Add(new LanguageInfo("tr"));
         var provider = new AbpCultureMenuItemUrlProvider(
             httpContextAccessor, localizationOptions, MsOptions.Create(abpLocOptions));
 
@@ -81,8 +100,8 @@ public class AbpCultureMenuItemUrlProvider_Tests
             CultureInfo.CurrentCulture = previousCulture;
         }
 
-        menu.Items[0].Url.ShouldBe("/home");
-        menu.Items[1].Url.ShouldBe("/about");
+        menu.Items[0].Url.ShouldBe("/zh-Hans/home");
+        menu.Items[1].Url.ShouldBe("/zh-Hans/about");
     }
 
     [Fact]
@@ -257,4 +276,5 @@ public class AbpCultureMenuItemUrlProvider_Tests
         }
         return menu;
     }
+
 }

modules/basic-theme/src/Volo.Abp.AspNetCore.Components.Server.BasicTheme/Themes/Basic/LoginDisplay.razor.cs

@@ -3,7 +3,7 @@ using System.Threading.Tasks;
 using Microsoft.AspNetCore.Components;
 using Microsoft.AspNetCore.Components.Routing;
 using Microsoft.AspNetCore.Http;
-using Microsoft.AspNetCore.Routing;
+using Microsoft.AspNetCore.RequestLocalization;
 using Volo.Abp.UI.Navigation;
 
 namespace Volo.Abp.AspNetCore.Components.Server.BasicTheme.Themes.Basic;
@@ -27,7 +27,7 @@ public partial class LoginDisplay : IDisposable
 
     protected string GetLoginUrl()
     {
-        var culture = HttpContextAccessor.HttpContext?.GetRouteValue("culture")?.ToString();
+        var culture = AbpRequestCultureCookieHelper.GetRouteCulture(HttpContextAccessor.HttpContext);
         return string.IsNullOrEmpty(culture) ? "Account/Login" : $"{culture}/Account/Login";
     }