https://dev.azure.com/umbraco/D-Team%20Tracker/_workitems/edit/7619 - Added request localization from the current user

src/Umbraco.Core/Security/AuthenticationExtensions.cs

@@ -16,12 +16,22 @@ namespace Umbraco.Core.Security
         /// </summary>
         /// <param name="identity"></param>
         public static void EnsureCulture(this IIdentity identity)
+        {
+            var culture = GetCulture(identity);
+            if (!(culture is null))
+            {
+                Thread.CurrentThread.CurrentUICulture = Thread.CurrentThread.CurrentCulture = culture;
+            }
+        }
+
+        public static CultureInfo GetCulture(this IIdentity identity)
         {
             if (identity is UmbracoBackOfficeIdentity umbIdentity && umbIdentity.IsAuthenticated)
             {
-                Thread.CurrentThread.CurrentUICulture =
-                    Thread.CurrentThread.CurrentCulture = UserCultures.GetOrAdd(umbIdentity.Culture, s => new CultureInfo(s));
+                return UserCultures.GetOrAdd(umbIdentity.Culture, s => new CultureInfo(s));
             }
+
+            return null;
         }
 
 

src/Umbraco.Web.Common/Extensions/UmbracoBackOfficeIdentityCultureProvider.cs

@@ -0,0 +1,22 @@
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Localization;
+using Umbraco.Core.Security;
+
+namespace Umbraco.Web.Common.Extensions
+{
+    public class UmbracoBackOfficeIdentityCultureProvider : RequestCultureProvider
+    {
+        public override Task<ProviderCultureResult> DetermineProviderCultureResult(HttpContext httpContext)
+        {
+            var culture = httpContext.User.Identity.GetCulture();
+
+            if (culture is null)
+            {
+                return NullProviderCultureResult;
+            }
+
+            return Task.FromResult(new ProviderCultureResult(culture.Name, culture.Name));
+        }
+    }
+}

src/Umbraco.Web.Common/Extensions/UmbracoCoreServiceCollectionExtensions.cs

@@ -1,10 +1,12 @@
 using System;
-using System.Collections;
 using System.Data.Common;
 using System.Data.SqlClient;
+using System.Globalization;
 using System.IO;
+using System.Linq;
 using System.Reflection;
 using System.Runtime.InteropServices;
+using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.Configuration;
@@ -13,7 +15,6 @@ using Microsoft.Extensions.Logging;
 using Serilog;
 using Serilog.Extensions.Hosting;
 using Serilog.Extensions.Logging;
-using Umbraco.Composing;
 using Umbraco.Configuration;
 using Umbraco.Core;
 using Umbraco.Core.Cache;
@@ -26,6 +27,7 @@ using Umbraco.Core.Persistence;
 using Umbraco.Core.Persistence.SqlSyntax;
 using Umbraco.Core.Runtime;
 using Umbraco.Web.Common.AspNetCore;
+using Umbraco.Web.Common.Extensions;
 using Umbraco.Web.Common.Profiler;
 
 namespace Umbraco.Extensions
@@ -156,6 +158,23 @@ namespace Umbraco.Extensions
             return services;
         }
 
+        public static IServiceCollection AddUmbracoRequestLocalization(this IServiceCollection services)
+        {
+            services.Configure<RequestLocalizationOptions>(options =>
+            {
+                var supportedCultures = CultureInfo
+                    .GetCultures(CultureTypes.AllCultures & ~ CultureTypes.NeutralCultures)
+                    .Where(cul => !String.IsNullOrEmpty(cul.Name))
+                    .ToArray();
+
+                options.SupportedCultures = supportedCultures;
+                options.SupportedUICultures = supportedCultures;
+                options.AddInitialRequestCultureProvider(new UmbracoBackOfficeIdentityCultureProvider());
+            });
+
+            return services;
+        }
+
         /// <summary>
         /// Adds the Umbraco Back Core requirements
         /// </summary>
@@ -182,6 +201,10 @@ namespace Umbraco.Extensions
             if (container is null) throw new ArgumentNullException(nameof(container));
             if (entryAssembly is null) throw new ArgumentNullException(nameof(entryAssembly));
 
+            // Set culture options
+            services.AddUmbracoRequestLocalization();
+
+            // Add supported databases
             services.AddUmbracoSqlCeSupport();
             services.AddUmbracoSqlServerSupport();
 
@@ -228,7 +251,7 @@ namespace Umbraco.Extensions
             factory = coreRuntime.Configure(container);
 
             return services;
-        }        
+        }
 
         private static ITypeFinder CreateTypeFinder(Core.Logging.ILogger logger, IProfiler profiler, IWebHostEnvironment webHostEnvironment, Assembly entryAssembly, ITypeFinderSettings typeFinderSettings)
         {

src/Umbraco.Web.UI.NetCore/Startup.cs

@@ -6,7 +6,6 @@ using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Umbraco.Extensions;
-using Umbraco.Web.Common.Middleware;
 
 namespace Umbraco.Web.UI.BackOffice
 {
@@ -80,6 +79,7 @@ namespace Umbraco.Web.UI.BackOffice
 
             app.UseUmbracoCore();
             app.UseUmbracoRouting();
+            app.UseRequestLocalization();
             app.UseUmbracoRequestLogging();
             app.UseUmbracoWebsite();
             app.UseUmbracoBackOffice();