ASP.NET Core - Yerelleştirme (Localization, Dil Desteği) | Perde Arkası #1

public interface IStringLocalizer
  {
    /// <summary>Gets the string resource with the given name.</summary>
    /// <param name="name">The name of the string resource.</param>
    /// <returns>The string resource as a <see cref="T:Microsoft.Extensions.Localization.LocalizedString" />.</returns>
    LocalizedString this[string name] { get; }

    /// <summary>
    /// Gets the string resource with the given name and formatted with the supplied arguments.
    /// </summary>
    /// <param name="name">The name of the string resource.</param>
    /// <param name="arguments">The values to format the string with.</param>
    /// <returns>The formatted string resource as a <see cref="T:Microsoft.Extensions.Localization.LocalizedString" />.</returns>
    LocalizedString this[string name, params object[] arguments] { get; }

    /// <summary>Gets all string resources.</summary>
    /// <param name="includeParentCultures">
    /// A <see cref="T:System.Boolean" /> indicating whether to include strings from parent cultures.
    /// </param>
    /// <returns>The strings.</returns>
    IEnumerable<LocalizedString> GetAllStrings(bool includeParentCultures);
  }

  public interface IStringLocalizerFactory
  {
    /// <summary>
    /// Creates an <see cref="T:Microsoft.Extensions.Localization.IStringLocalizer" /> using the <see cref="T:System.Reflection.Assembly" /> and
    /// <see cref="P:System.Type.FullName" /> of the specified <see cref="T:System.Type" />.
    /// </summary>
    /// <param name="resourceSource">The <see cref="T:System.Type" />.</param>
    /// <returns>The <see cref="T:Microsoft.Extensions.Localization.IStringLocalizer" />.</returns>
    IStringLocalizer Create(Type resourceSource);

    /// <summary>
    /// Creates an <see cref="T:Microsoft.Extensions.Localization.IStringLocalizer" />.
    /// </summary>
    /// <param name="baseName">The base name of the resource to load strings from.</param>
    /// <param name="location">The location to load resources from.</param>
    /// <returns>The <see cref="T:Microsoft.Extensions.Localization.IStringLocalizer" />.</returns>
    IStringLocalizer Create(string baseName, string location);
  }

// Configure services...
builder.Services.AddLocalization();

// IStringLocalizerFactory için ResourceManagerStringLocalizerFactory kaydedilir.
// IStringLocalizer<T> için StringLocalizer<T> kaydedilir.

// Controller'da ise şöyle kullanılır:

public class HomeController : Controller {
    private IStringLocalizer<HomeController> _localizer;
    public HomeController(IStringLocalizer<HomeController> localizer) {
        _localizer = localizer;
    }
 
    public View Index() {
        ViewBag["Karsilama"] = _localizer["Karsilama"];
    }
}

// Burada Constructor'dan localizer istediğimizde DI -> IStringLocalizerFactory'i çözer -> ResourceManagerStringLocalizerFactory
// Factory -> Create(typeof(HomeController)) girer -> sonuç: ResourceManagerStringLocalizer
// Derlenmiş olan RESX dosyasına göre string'i verir.

IStringLocalizer<T>
        |
        v
StringLocalizer<T>
        |
        v
IStringLocalizerFactory
        |
        v
ResourceManagerStringLocalizerFactory
        |
        v
ResourceManagerStringLocalizer
        |
        v
.resx

public RequestLocalizationMiddleware(RequestDelegate next, IOptions<RequestLocalizationOptions> options, ILoggerFactory loggerFactory)
    {
        ArgumentNullException.ThrowIfNull(options);

        _next = next ?? throw new ArgumentNullException(nameof(next));
        _logger = loggerFactory?.CreateLogger<RequestLocalizationMiddleware>() ?? throw new ArgumentNullException(nameof(loggerFactory));
        _options = options.Value;
    }

public RequestLocalizationOptions()
{
   RequestCultureProviders = new List<IRequestCultureProvider>
   {
       new QueryStringRequestCultureProvider { Options = this },
       new CookieRequestCultureProvider { Options = this },
       new AcceptLanguageHeaderRequestCultureProvider { Options = this }
   };
}

using Microsoft.AspNetCore.Http;using Microsoft.AspNetCore.Localization;using System;using System.Threading.Tasks;

public class HeaderRequestCultureProvider : RequestCultureProvider{private readonly string _headerName;

public HeaderRequestCultureProvider(string headerName = "X-Language")
{
    _headerName = headerName;
}

public override Task<ProviderCultureResult> DetermineProviderCultureResult(HttpContext httpContext)
{
    ArgumentNullException.ThrowIfNull(httpContext);

    // İstekteki header'ı oku
    if (httpContext.Request.Headers.TryGetValue(_headerName, out var languageHeader))
    {
        var requestCulture = languageHeader.ToString();

        if (!string.IsNullOrWhiteSpace(requestCulture))
        {
            // Hem Culture hem de UICulture için aynı değeri set ediyoruz
            var result = new ProviderCultureResult(requestCulture, requestCulture);
            return Task.FromResult<ProviderCultureResult>(result);
        }
    }

    // Eğer header bulunamazsa null dönerek sıradaki provider'a pasla
    return Task.FromResult<ProviderCultureResult>(null);}
}

@using Microsoft.AspNetCore.Mvc.Localization@inject IViewLocalizer Localizer

builder.Services.AddControllersWithViews().AddDataAnnotationsLocalization(options => {
     options.DataAnnotationLocalizerProvider = (type, factory) =>
           factory.Create(typeof(SharedResource)); // Ortak bir resource dosyası kullanmak için
     }
);

public class LoginModel {
     [Required(ErrorMessage = "EmailRequired")]
     [EmailAddress(ErrorMessage = "InvalidEmail")]
     public string Email { get; set; } = string.Empty;
}

using System.Globalization;using Microsoft.AspNetCore.Localization;

var builder = WebApplication.CreateBuilder(args);
// 1. Localization Servislerini Kaydet
builder.Services.AddLocalization(options => options.ResourcesPath = "Resources");
builder.Services.AddControllersWithViews().AddViewLocalization().AddDataAnnotationsLocalization();

var app = builder.Build();
// 2. Desteklenen Dilleri ve Seçenekleri Tanımla
var supportedCultures = new[]{new CultureInfo("tr-TR"),new CultureInfo("en-US")};
var localizationOptions = new RequestLocalizationOptions{DefaultRequestCulture = new RequestCulture("tr-TR"),SupportedCultures = supportedCultures,SupportedUICultures = supportedCultures};
// 3. Custom Provider'ımızı listenin EN BAŞINA ekleyelim (Öncelikli olması için)
localizationOptions.RequestCultureProviders.Insert(0, new HeaderRequestCultureProvider("X-Language"));
// 4. Middleware Pipeline'a Ekle
app.UseRequestLocalization(localizationOptions);

app.UseStaticFiles()
;app.UseRouting();app.UseAuthorization();
app.MapControllerRoute(name: "default",pattern: "{controller=Home}/{action=Index}/{id?}");
app.Run();