Localization and redirect in blazor Server

i have added localization to my blazor app to manage auto-traslation of my app's text.
I made it using Apicontroller.

To be more clear:

On Program.cs i have added:

    builder.Services.AddControllers();
    builder.Services.AddLocalization(x => x.ResourcesPath = "ResourcesFolder");

and

var localizeoptions = new RequestLocalizationOptions().SetDefaultCulture("it-IT")
    .AddSupportedCultures("it-IT", "en-US")
    .AddSupportedUICultures("it-IT", "en-US");

app.UseRequestLocalization(localizeoptions);
app.MapControllers();

On Index.razor:

@inject Microsoft.Extensions.Localization.IStringLocalizer<Index> localizer

and in the html the auto translate text:

 <h2>@localizer["Customer"]</h2>

"Customer" is in every resx file ( in my app en-US e it-IT translation).

The traslation is managed using a controllor for every languge. Example for en-US:

[Route("/[controller]")]
[ApiController]
public class enUS : ControllerBase
{

    public ActionResult SetCulture()
    {
        IRequestCultureFeature culture = HttpContext.Features.Get<IRequestCultureFeature>();
        Response.Cookies.Append(CookieRequestCultureProvider.DefaultCookieName,
        CookieRequestCultureProvider.MakeCookieValue(new RequestCulture("en-US")));


        return Redirect("/");
    }
}

This is working pretty well. If i open the web app with https://localhost:7058/enUS is in english and with https://localhost:7058/itIT is in intalian.

The problem is that if i want to specify parameter in the link ( for example https://localhost:7058/enUS/?link=OQ== ) with the line code return Redirect("/"); on the controller i will be redirected to https://localhost:7058 with english languange. The parameter "link" is lost.

There is a way to read parameter inside the controllor and then redirect to the correct link?

You can get the link parameter if you pass the query string in the redirect, like this:

return Redirect("/" + Request.QueryString);

If you check the Request property you can find the correct URL and redirect the user.

But with you current implementation this is an endpoint that only sets the culture if you go here: https://localhost:7058/enUS . If you want to have the culture in your path and change it via url. For example like this: https://www.microsoft.com/en-us/windows/ . You have to create a BaseController and have your controllers inherit from it. For example:

[Route("/[controller]/{culture?}")]
[ApiController]
public class MyBaseController : Controller
{
    public override void OnActionExecuting( ActionExecutingContext filterContext)
    {
        string culture = filterContext.RouteData.Values["culture"]?.ToString() ?? "en";

        var cultureInfo = CultureInfo.GetCultureInfo(culture);
        Thread.CurrentThread.CurrentCulture = cultureInfo;
        Thread.CurrentThread.CurrentUICulture = cultureInfo;

        Response.Cookies.Append(CookieRequestCultureProvider.DefaultCookieName,
        CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(culture)));

        base.OnActionExecuting(filterContext);
    }
}

And adjust it to your needs. Or it can also be done with a Middleware and change the default Routing, I haven't tried it but I see a lot of examples online.